Multi Collagen Peptides by Purely Optimal

LIKELY EFFECTIVE

• Biotin deficiency. Oral and injectable biotin prevents and treats biotin deficiency. Details: Biotin up to 10 mg daily has been used to treat and prevent biotin deficiency. Injections of biotin 150 mcg daily for 3-5 days have been used in adults. Biotin deficiency might occur due to different etiologies such as inherited biotinidase deficiency, malnutrition, chronic use of anticonvulsants, pregnancy, and excessive and chronic raw egg consumption (6243,19347). A very small study in newborns aged 1-6 months shows that adding biotin to infant formula safely improves biotin status in formula-fed infants (111365). The validity of these findings is limited by a lack of blinding, no randomization, and the small sample size.

POSSIBLY INEFFECTIVE

• Multiple sclerosis (MS). In spite of contrary reports, high-dose biotin (300 mg daily) does not reduce disability in patients with progressive MS. It also does not seem to be linked to an increased risk for relapse. Details: Although most earlier research suggested benefit, the highest quality evidence shows that high-dose biotin does not improve outcomes in progressive MS (95662,102963,102966,104011). A large multi-centered randomized clinical trial (SPI2) in patients with progressive MS and high disability shows that taking biotin 100 mg three times daily for 15 months does not improve disability, as measured on the expanded disability status scale (EDSS), or 25-foot walking time, when compared with placebo. The SPI2 clinical trial also did not find that biotin increases the rate of relapse (104011), a concern raised in one observational study of high-dose biotin (104000). Also, a large observational study of adults with progressive MS failed to identity an increase in annualized relapse rates in patients that reported taking biotin when compared with controls (105716). Other observational research has also found no effect on the relapse risk (102963,102964). There is some speculation that any increased rate of relapse identified in some high-dose biotin cohorts might be due to detection bias or reduced compliance with disease-modifying therapies.
• Seborrheic dermatitis. Oral biotin doesn't seem to improve seborrheic dermatitis of infancy. Details: A clinical trial in infants with seborrheic dermatitis shows that biotin given by mouth does not improve symptoms when compared with placebo (8469).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alopecia areata. It is unclear if oral biotin is beneficial for alopecia areata. Details: A small clinical study in healthy adults with alopecia areata shows that weekly injections of intramuscular biotin 5 mg/1 mL and dexpanthenol 250 mg/2 mL for 6 weeks reduces hair fall count and transiently increases hair density compared with baseline (111366). The validity of these findings is limited by a lack of a placebo control group, small sample size, and short duration of treatment. It is unclear if the effects are due to biotin, dexpanthenol, or the combination. Another small clinical study in 9-year-old children with alopecia areata shows that taking biotin 20 mg with zinc aspartate 100 mg orally along with topical application of clobetasol propionate 0.025% daily for one year promotes hair regrowth in 33% of children, compared with 0% in the group receiving the steroid deflazacort (6932). It is unclear if these effects are due to biotin, zinc, topical clobetasol, or the combination.
• Amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease). Although there is interest in using oral biotin for ALS, there is insufficient reliable information about the clinical effects of biotin for this condition.
• Biotin-thiamine-responsive basal ganglia disease. Adding oral biotin to oral thiamine does not seem to improve most symptoms associated with this condition, although it may slightly speed recovery from acute crisis in children. Details: A small case series in children ages 1-12 years with biotin-thiamine-responsive basal ganglia disease has found that adding biotin 5 mg/kg daily to thiamine 40 mg/kg daily for 30 months is not associated with additional symptomatic improvement in encephalopathy, seizures, dystonia, or other neurologic sequelae when compared with taking only thiamine. However, taking biotin with thiamine is associated with a 1-day reduction in recovery from acute crisis when compared with thiamine alone (95661).
• Brittle nails. Low quality clinical studies suggest that oral biotin might improve nail thickness and prevent the splitting of brittle nails. Details: Some small, low quality clinical studies in people with brittle nails shows that taking biotin 2.5 mg orally daily for 1.5 to 15 months increases nail thickness and decreases the splitting of fingernails and toenails in some people when compared with baseline (171,35593). The validity of these findings is limited by the small study sizes and the lack of a comparator group.
• Depression. Although there is interest in using oral biotin for mild depression, there is insufficient reliable information about the clinical effects of biotin for this condition.
• Diabetes. It is unclear if oral biotin is beneficial for type 2 diabetes. Details: A meta-analysis of randomized controlled trials shows that taking biotin 1.5-15 mg orally daily for 1-3 months does not improve fasting blood glucose or serum insulin levels when compared with placebo. However, the validity of these results is limited by inclusion of subjects with and without diabetes (110044). A very small study in adults with type 2 diabetes also shows that taking biotin 5 mg three times daily for 28 days does not affect glucose or insulin levels when compared to baseline (11579). Biotin has also been studied in combination with other ingredients. Preliminary clinical research shows that a taking a specific supplement containing a combination of biotin 2 mg and chromium picolinate 600 mcg (Diachrome, Nutrition 21) can lower blood glucose and glycated hemoglobin levels in patients with type 2 diabetes who are poorly controlled on oral hypoglycemic drugs (12385,12390,15169). It is unclear if these effects are due to biotin, chromium, or the combination.
• Diabetic neuropathy. Although there is interest in using oral and intramuscular biotin for diabetic neuropathy, there is insufficient reliable information about the clinical effects of biotin for this condition.
• Muscle cramps. It is unclear if biotin is beneficial for improving muscle cramps in patients undergoing hemodialysis. Details: Patients undergoing hemodialysis are prone to muscle cramps. A small clinical study in patients with hemodialysis-related muscle cramps shows that taking biotin 1 mg in the morning daily for at least one week prevents and reduces severity of muscle cramps when compared to baseline. Cessation of biotin led to recurrence of cramps, and restarting oral biotin led to resolution of cramps during hemodialysis (89475). The validity of these findings is limited by the lack of comparator group. More evidence is needed to rate biotin for these uses.

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POSSIBLY EFFECTIVE

• Aging skin. Oral collagen peptides seem to improve skin hydration and elasticity in older adults. However, it is unclear if any improvements related to wrinkles are cosmetically important. Details: Meta-analyses of the available research, as well as multiple individual clinical studies, show that collagen peptide products, taken in doses of 372 mg to 12 grams daily for 4-12 weeks, improve skin hydration and elasticity in older adults. Studied products include Peptan-F or Peptan-P (Rousselot), Wellnex (Nitta Gelatin), Gold Collagen Active (Minerva Research Labs), VERISOL (Gelita AG), and Nippi peptide FCP-EX (Nippi/Shizuoka) (97632,100703,101597,104647,107460,112457). Pooled study results also suggest that hydrolyzed collagen sourced from fish improves skin hydration and elasticity, while collagen peptides originating from chickens seems to modestly improve skin elasticity but not hydration. Collagen peptides derived from bovine do not seem to improve skin hydration or elasticity (112457). Despite research showing improvement in skin hydration and elasticity, it is unclear if collagen peptides reduce skin wrinkles to a cosmetically significant degree, as most studies have not evaluated this outcome. In one clinical study, taking a freshwater fish-derived collagen peptide (Vinh Wellness Collagen, Vinh Hoan Corporation) 10 grams every morning reduced wrinkle count in the nasolabial region of the right side, but not the left side, of the face by 24% when compared with placebo. Collagen peptides did not improve participant-reported measures of wrinkles, elasticity, hydration, and others, when compared with placebo (104639). Another clinical study shows that taking a specific fish scale-derived collagen peptide (Wellnex, Nitta Gelatin) with either a high or low ratio of prolyl-hydroxyproline and hydroxylpropyl-glycine as 5 grams orally daily for 8 weeks modestly improves wrinkle depth and roughness, but not wrinkle volume, when compared with placebo. The product with a high ratio of dipeptides had a larger effect (97632). Also, one clinical study shows that taking a specific product containing porcine collagen type I peptides (VERISOL, Gelita AG) 2.5 grams daily for 8 weeks reduces eye wrinkle volume by 20% when compared with placebo (101648). Two similar moderate-size clinical studies in middle-aged adults with crow's feet wrinkles and dry skin show that taking specific low-molecular-weight fish-derived collagen peptide products (Geltech Co.; CPNS) at doses of 2000 mg or 1650 mg, respectively, daily for 12 weeks improves eye wrinkles, skin hydration, and elasticity when compared with placebo (110729,110730). While investigator satisfaction scores regarding wrinkle reduction were modestly improved, participant satisfaction was not improved (110729). Small clinical studies have shown contradictory findings when collagen peptides are taken in combination with other ingredients. In one clinical trial, a specific drink (Diva Luxe) providing fish collagen peptides 5.5 grams plus Chenopodium formosanum extract 1 gram daily for 8 weeks improved some measures of skin brightness and hydration, but not wrinkles and crow's feet, when compared with placebo (104646). Another small clinical study shows that taking collagen peptides 4 grams daily in combination with coenzyme Q10 50 mg, vitamin C, vitamin A, and biotin for 12 weeks reduces wrinkles and improves skin smoothness by a small amount when compared with placebo. However, there was no difference in skin elasticity or hydration (104638). A clinical study in older females shows that taking collagen peptides 9 grams in combination with zinc and vitamins A, C, and E daily for 90 days increases stratum corneum water content and skin viscoelasticity when compared with placebo. However, it is unclear if the improvement from baseline differed between groups. Small improvements in dermal echogenicity, wrinkles, or skin pores were noted in some facial regions, but the lack of statistical comparison to placebo limits the validity of these findings (107464). Some small clinical studies have shown mixed effects with low doses of collagen peptides from preliminary clinical research using BioCell Collagen (BioCell Technology, LLC) or Celergen (Laboratories-Dom) (28681,97930). It is unclear if any improvements from these studies are due to collagen peptides, other ingredients, or the combinations. Topical application of collagen peptides has been minimally evaluated. A very small observational study in older adults has found that application of a carbopol gel containing collagen peptides 1% to the periorbital area twice daily for 8 weeks is associated with increased skin hydration and elasticity and reduced transepidermal water loss, skin roughness, and wrinkles when compared with baseline (107459). The validity of these findings is limited by poor study methodology, lack of statistical comparison to baseline, and lack of a comparator group.
• Dry skin. Oral collagen peptides seem to improve skin hydration and elasticity in adults with dry skin. However, their effect on other measures of dry skin is unclear. Details: A meta-analysis of 19 clinical studies, along with several small and moderate-sized individual studies, some of which are included in the meta-analysis, show that taking collagen peptides 372 mg to 12 grams daily for 4-12 weeks improves skin hydration and elasticity when compared with placebo in healthy adults (107461,110729,110730,112457,112458). Some studies show that collagen peptides improve skin roughness (107461), decrease peeling (110729,110730), and increase stratum corneum and epidermis water content (107462) but not skin gloss (107461) or elasticity (107462). Some research shows that collagen peptides reduce transepidermal water loss (107462), while another study shows no change (107461). Subgroup analysis of the meta-analysis suggests that hydrolyzed collagen sourced from fish improves skin hydration and elasticity the most, while collagen peptides originating from chicken seem to modestly improve skin elasticity but not hydration. Collagen peptides from bovine do not seem to improve skin hydration or elasticity (112457). Studied products include FCP-Z (Nippi Co., Ltd), Geltech Co., CPNS, and GPVGPS Collagen (Daehan Chemtech) (107462,110729,110730,112458). Collagen peptides have also been evaluated in combination with other ingredients. A small clinical study in healthy adults with low skin moisture shows that drinking 30 mL of a beverage containing fish scale-derived collagen peptides 10 grams and ornithine 400 mg (FUJIFILM) daily for 8 weeks does not improve skin moisture but seems to improve skin elasticity and reduce water loss when compared with placebo (101607). Another very small clinical study in a mixed population of patients with dry skin and mild atopic dermatitis shows that twice daily application of an emollient containing collagen peptides, soluble proteoglycan, and hyaluronic acid for 4 weeks reduces itching severity from moderate at baseline to mild or almost none. Transepidermal water loss and skin hydration also improved when compared to baseline (107465). The validity of these findings is limited by the lack of a comparator group. Both of these studies are limited by their small size, and it is unclear if any improvements are due to collagen peptides, other ingredients, or the combination.

POSSIBLY INEFFECTIVE

• Muscle strength. Most research suggests that oral collagen peptides do not improve leg strength. However, they may improve hand-grip strength and fat-free mass. Details: Small clinical studies in healthy male and female athletes or non-athletes undergoing resistance or other training show that taking collagen peptides 15-30 grams daily or after training sessions for up to 15 weeks, with or without vitamin C, does not improve leg strength (i.e. squat strength, knee extension, or flexor strength) when compared with placebo (101608,104641,107457,110668,110669). Similarly, 2 very small clinical studies in healthy adults show that taking a specific oral collagen peptide product (Bodybalance, Gelita AG) 5-15 grams daily while completing a resistance training program for 14-15 weeks increases patellar tendon cross-sectional area but does not improve most measures of tendinous tissue remodeling including patellar tendon size, vastus lateralis aponeurosis size, patellar tendon mechanical properties, tendon stiffness, maximal knee extension strength, or rectus femoris muscle cross-sectional area when compared with placebo (112452,112454). However, a small clinical study with the same product in untrained females aged 18-50 years shows that taking 15 grams daily in addition to resistance training three times weekly for 12 weeks improves hand-grip strength when compared with resistance training and placebo (101608). In untrained males aged 30-60 years, taking the same dose of this collagen peptide product along with resistance training for 12 weeks improves fat-free mass by 3 kg, compared with 2 kg with resistance training and placebo. A post-hoc exploratory analysis suggests that the effects seen in males are similar to those seen with whey protein (107457).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Although there has been interest in using oral collagen peptides for acne, there is insufficient reliable information about the clinical effects of collagen peptides for this condition.
• Androgenic alopecia. Oral collagen peptides have only been evaluated in combination with other ingredients, their effect when used alone is unclear. Details: A moderate-sized clinical study in adults with androgenic alopecia or telogen effluvium shows that taking a combination product containing hydrolyzed collagen 300 mg, taurine, cysteine, methionine, iron, and selenium (GFM Oral, Cantabria Labs) daily along with conventional therapy, consisting primarily of finasteride or minoxidil, for 12 weeks improves hair loss when compared with conventional therapy alone (111636). It is unclear if this effect is due to collagen peptides, other ingredients, or the combination.
• Athletic performance. It is unclear if oral collagen peptides improve performance in most athletes. Details: In recreationally active female runners undergoing resistance and endurance training 3 times weekly, clinical research shows that taking collagen peptides 7.5 grams twice daily for 12 weeks increases running distance by approximately 1,034 meters, compared with an increase of 703 meters in those taking placebo, although there was no effect on speed (104641). A clinical study in healthy young male athletes undergoing heavy strength and power training shows that taking collagen peptides 20 grams and vitamin C 50 mg daily for 3 weeks improves squat performance and countermovement jump performance when compared with placebo. However, removal of a single outlier negated the statistical significance of most of these findings (107456). Also, it is unclear if any improvements from this study are due to collagen peptides, vitamin C, or the combination.
• Atopic dermatitis (eczema). It is unclear if oral or topical collagen peptides are beneficial for improving the severity of eczema. Details: A small clinical study in patients with atopic dermatitis shows that taking a porcine skin-derived collagen peptide with a high ratio of tripeptides with glycine-X-Y sequences, 3.9 grams daily for 12 weeks, improves symptoms and severity of eczema when compared to baseline. There was no improvement in the group taking the same dose of porcine skin-derived collagen peptide without the high ratio of tripeptides (101605). Another very small clinical study in a mixed population of patients with atopic dermatitis and dry skin shows that twice daily application of an emollient containing collagen peptides, soluble proteoglycan, and hyaluronic acid for 4 weeks reduces itching severity from moderate at baseline to mild or almost none. Transepidermal water loss and skin hydration also improved when compared to baseline (107465). It is unclear if any improvements are due to collagen peptides, the other ingredients, or the combination. Both of these studies are limited by their small size and lack of comparator groups.
• Burns. Some preliminary clinical research suggests that oral collagen peptides might reduce the time needed for burn healing. Details: In male patients with 20% to 30% body surface area burns, a small clinical trial shows that taking a collagen-based supplement providing collagen peptides (Amutiya, Qom) 36 grams daily for 4 weeks improves wound healing when compared with taking an isocaloric supplement containing the same amount of soy protein. Complete wound healing occurred in 50% and 100% of patients taking collagen for 2 and 4 weeks, respectively, compared with 7% and 40% of those taking the isocaloric product. The duration of hospital stay was not significantly different between the two groups (104642). A small clinical study in hospitalized adults with 20-45% body surface area 2nd or 3rd degree burns shows that consuming a beverage containing collagen peptides 40 grams daily for 4 weeks shortens the time to wound healing, improves scar scores, and reduces the duration of hospital stays but does not limit wound infections when compared with placebo. Adding fish oil 3 grams daily did not further improve outcomes (110667).
• Brittle nails. One small clinical study suggests that oral collagen peptides may improve nail health in people with brittle nails. Details: A small clinical study shows that taking a specific porcine type I collagen peptide product (VERISOL, Gelita AG) 2.5 grams daily for 6 months improves overall symptoms of brittle nail syndrome, increases nail growth rate by 12%, and reduces broken nail frequency by 42% when compared with baseline (101606). This study was limited by its small size and lack of a comparator group.
• Cellulite. One small clinical study suggests that oral collagen peptides may reduce cellulite. Details: In people with cellulite, a small clinical study shows that taking specific collagen peptides (VERISOL by Gelita AG) 2.5 grams daily for 6 months seems to reduce cellulite, skin waviness, and dermal density by a small amount when compared with placebo (101619).
• Cognitive function. It is unclear if oral collagen peptides are beneficial for improving memory. Details: In healthy adults, preliminary clinical research shows that taking collagen peptides 5 grams daily for 4 weeks improves some measures of memory and verbal learning when compared to baseline (104643). This study was limited by its small size and lack of a comparator group.
• Dermatoporosis. One small clinical study suggests that using oral or topical collagen peptides does not improve this condition. Details: A small clinical study in post-menopausal patients aged 70 years on average with mild dermatoporosis shows that taking collagen peptides 5 grams daily, applying a collagen peptides 2.5% serum 3 pumps nightly to each forearm, or using these in combination for 6 months does not improve skin lesions, epidermal thickness, collagen or elastin density, or patient perception of skin improvement when compared with placebo (110731). However, it is unclear if these results apply to patients with more severe dermatoporosis.
• Diabetes. Some preliminary clinical research suggests that oral collagen peptides might have a small effect on glycemic indices. Details: Preliminary clinical research in patients with type 2 diabetes shows that taking fish-derived collagen peptides 6.5 grams orally twice daily for 3 months, in addition to treatment with antidiabetes drugs, may modestly reduce levels of fasting blood glucose, glycated hemoglobin, and fasting blood insulin and may increase levels of insulin sensitivity when compared with antidiabetes drugs and placebo (101626,101627).
• Erythema. It is unclear if oral collagen peptides are beneficial for erythema. Details: A moderate-sized clinical study in adults with dry and wrinkled eye skin shows that taking low-molecular weight collagen peptides (GPVGPS Collagen, Daehan Chemtech) 2000 mg daily for 12 weeks reduces erythema index when compared with placebo (112458).
• Exercise-induced gastrointestinal (GI) symptoms. It is unclear if oral collagen peptides prevent GI symptoms due to exercise. Details: A small crossover study in moderately well-trained young adults shows that taking collagen peptides 10 grams daily for 7 days prior to rigorous treadmill exercise does not limit GI symptoms but may attenuate some markers of GI distress when compared with placebo (110665).
• Exercise-induced muscle soreness. It is unclear if oral collagen peptides prevent muscle soreness after exercise. Details: Preliminary clinical research in a small number of healthy, recreationally active adults shows that taking collagen peptides (Peptan, Rousselot BVBA, Collagen Peptides, Vital Proteins) 10-15 grams twice daily, starting 7 days prior to strenuous exercise and continuing for 2-5 days after, does not reduce muscle soreness when compared with placebo (100700,104648). However, there was a small benefit on the recovery of countermovement jump ability within 24 hours (104648). Furthermore, another small clinical study in adults unaccustomed to exercise shows that taking collagen peptides 10 grams daily for 33 days modestly reduces muscle soreness and fatigue immediately after the exercise load, but not 2 hours after exercise or the next morning, when compared with placebo (111639). Also, a small clinical study in active middle-aged adults shows that taking specific collagen peptides (SOLUGEL Collagen Peptides, PB Leiner) 10 grams daily for 6 months improves pain in those who exercise frequently (>188 minutes weekly) when compared with placebo. However, collagen peptides do not seem to improve pain in low frequency exercisers (<188 minutes weekly) (112455). Collagen peptides have also been evaluated in combination with other ingredients. One preliminary clinical study in healthy, recreationally active adults shows that taking a specific product (BioCell Collagen, BioCell Technology, LLC) containing collagen peptides from chicken collagen type II, hyaluronic acid, and chondroitin sulfate 1.5 grams twice daily for 6 weeks prior to two bouts of intense resistance exercise attenuates increases in biomarkers of muscle damage and decreases delayed onset muscle soreness when compared with placebo (96301). It is unclear if these benefits are due to collagen peptides, other ingredients or the combination.
• Gingivitis. It is unclear if oral collagen peptides are beneficial for patients with gingivitis. Details: A small clinical study in patients with mild-to-moderate chronic gingivitis shows that taking a specific collagen peptide product (Verisol B, Gelita AG) 5 grams daily for 90 days following mechanical plaque removal reduces bleeding and inflammation but does not improve plaque scores when compared with placebo (110666).
• Hypertension. Limited research suggests that oral collagen peptides may lower systolic or diastolic blood pressure. However, results are inconsistent. Details: One preliminary clinical study in patients with hypertension and type 2 diabetes shows that taking fish-derived collagen peptides 6.5 grams twice daily for 3 months modestly reduces diastolic, but not systolic, blood pressure when compared with placebo (101626). Another small clinical study in patients with mildly elevated blood pressure shows that taking a test food containing chicken leg-derived collagen peptides 2.9 grams daily for 12 weeks lowers systolic, but not diastolic, blood pressure when compared with placebo (101610). An additional small clinical study in patients with mild hypertension shows that taking chicken leg-derived collagen peptides 5.2 grams daily 4 weeks reduces systolic blood pressure by 12 mmHg when compared with baseline (101618). This study was limited by its small size and lack of a comparator group. The reasons for conflicting data are unclear.
• Insomnia. It is unclear if oral collagen peptides are beneficial for insomnia. Details: A very small clinical study in physically active males with difficulty sleeping shows that taking collagen peptides 15 grams before bedtime for 7 nights reduces the frequency of nocturnal awakenings and improves cognitive accuracy but does not improve objective measures of total sleep time, latency, efficiency, stage changes, waking after sleep onset, other cognitive function measures, or subjective measures of sleepiness, fatigue, and sleep quality when compared with placebo (112459).
• Joint pain. Most research shows that oral collagen peptides might moderately reduce joint pain in young athletes. However, evidence in elderly patients is conflicting. Details: Preliminary clinical research in student athletes with joint pain shows that taking a specific collagen peptide product (FORTIGEL, Gelita AG) 10 grams in 25 mL of liquid daily for 24 weeks modestly improves pain during movement and at rest when compared with placebo (101601). Other clinical research in young adults exercising or participating in sports at least 3 hours weekly with activity-related knee pain shows that taking this same product 5 grams daily for 12 weeks reduces pain intensity during activity by 38% to 41%, compared with a 26% to 28% reduction in those taking placebo. However, there was no improvement in pain at rest or after the activity when compared with placebo (97623,107454). Furthermore, it is not clear if these effects are clinically significant. Research on the use of collagen peptides in older patients is conflicting. A small clinical study in otherwise healthy patients aged 40-65 years with joint discomfort shows that taking a specific collagen peptides product (AVC-H2, Avicenna) 1.25 grams twice daily for 8 weeks improves overall Western Ontario and McMaster Universities Osteoarthritis (WOMAC) scores by 37% at 4 weeks, compared with 14% in those receiving placebo. However, this difference in improvement was no longer significant at 8 weeks. Collagen peptides also improved the physical activity and stiffness subdomains, but not the pain subdomain, at 4 and 8 weeks when compared with placebo (107455). A larger clinical study in patients 50 years or older with general joint pain shows that taking a specific collagen peptides product (Genacol) 1200 mg daily for 6 months does not reduce pain or improve function when compared with placebo (97657). However, collagen peptides used in combination with other ingredients have shown benefit. Preliminary clinical research in patients 51-70 years of age shows that taking a specific combination product (Gold Collagen Active, Minerva Research Labs) containing fish collagen peptides 4 grams, glucosamine hydrochloride 1000 mg, chondroitin sulfate 500 mg, L-carnitine 200 mg, and other ingredients daily for 90 days reduces joint pain by 43% when compared with baseline, while patients taking placebo saw negligible improvement in pain. A greater percentage of patients taking this product also perceived improvements in joint discomfort, flexibility, mobility, and rigidity when compared with placebo (100703). It is unclear if these effects are due to collagen peptides, other ingredients, or the combination.
• Obesity. It is unclear if oral collagen peptides are beneficial for weight loss. Details: A preliminary clinical study in adults with overweight shows that taking skate skin-derived collagen peptides 2 grams daily for 12 weeks modestly reduces body fat mass by 1.2 kg, compared with an increase of 0.3 kg in the placebo group (101621). It is unclear if collagen peptides improve weight loss or reduce body fat mass in the long-term.
• Osteoarthritis. Most research suggests that oral collagen peptides improve pain in patients with knee osteoarthritis; however, any improvement is modest and may not be considered clinically significant. Details: A meta-analysis of 3 clinical studies, all of which are included below, in adults with knee osteoarthritis shows that taking collagen peptides or hydrolyzed collagen reduces pain when compared with placebo (112456). Clinical research shows that taking specific collagen peptides (Colnatur, Protein SA) 10 grams daily for 5 months increases the number of patients who experience at least a 30% improvement in pain by approximately 42% when compared with placebo. However, there is no difference between groups when the Western Ontario and McMaster Universities (WOMAC) scale is used. Patients with the greatest joint deterioration at baseline, as well as those with the lowest dietary meat intake, seemed most likely to experience benefit from collagen peptides (97635). Another small clinical study shows that taking collagen peptides isolated from pork skin and bovine bone (Nitta Gelatin Inc.) 5 grams dissolved in 250 mL water or milk twice daily after food for 13 weeks modestly improves pain when compared with placebo (101611). Another small clinical study in patients over 40 years old shows that taking collagen peptides (Colatech) 10 grams daily for 90 days reduces pain by about 2 points on a 100-point scale, compared with a 0.9-point reduction with glucosamine sulfate 1.5 grams. Ibuprofen use was not affected (101622). One multicenter clinical study shows that taking collagen peptides 10 grams daily for 6 months does not relieve pain or improve joint function when compared with placebo, although a trend towards reduced pain and improved joint function was observed in patients with severe symptoms at baseline (7704). Collagen peptides have also been evaluated in combination with other ingredients. Clinical research in patients with osteoarthritis of the knee, hip, or hand shows that taking a specific product (BioCell Collagen, BioCell Technology, LLC) containing collagen peptides from chicken collagen type II, hyaluronic acid, and chondroitin sulfate 1 gram twice daily for up to 10 weeks reduces pain and the need for rescue analgesics and increases physical activity when compared with placebo (28678,28680). Similarly, a moderate-size clinical study in patients aged 45-75 years with mild to moderate knee osteoarthritis undergoing resistance exercise twice weekly shows that taking a specific product (Suntory Beverage and Food Asia) containing collagen peptides from chicken collagen type II, hyaluronic acid, and chondroitin sulfate 2 grams daily for 24 weeks does not improve WOMAC scores when compared with glucosamine 1.5 grams daily or placebo, but may modestly improve pain scores when compared with placebo. However, the use of rescue analgesics was not assessed. Adding essence of chicken 5.81 grams daily to collagen peptides did not improve WOMAC or pain scores (110670). Also, preliminary clinical research in patients with knee osteoarthrosis shows that taking a specific product (Ialoral 1500, PharmaSuisse Laboratories Srl) containing collagen peptides, chondroitin sulfate, hyaluronic acid, and keratin peptides for 4 weeks improves pain and function by a moderate amount when compared with baseline (104645). However, the validity of these findings is limited by the lack of statistical comparison to the control group. It is unclear if these effects are due to collagen peptides, other ingredients, or the combination.
• Osteopenia. It is unclear if oral collagen peptides prevent loss of bone mineral density (BMD) in postmenopausal adults. Details: A large clinical study in patients with reduced BMD after menopause shows that taking specific collagen peptides (Fortibone, Gelita AG) 5 grams daily for 12 months increases BMD of the spine and the femoral neck by 3% and 7%, respectively, compared with losses of 1% with placebo (101609). In a very small observational extension of this study, BMD continued to increase over an additional 4 years when compared with baseline. However, the validity of these findings is limited by the lack of a comparator group (107340). Collagen peptides have also been evaluated in combination with calcium and vitamin D. In patients with osteopenia after menopause, a small clinical study shows that taking collagen peptides calcium chelate 5 grams, containing elemental calcium 500 mg and vitamin D3 200 IU, daily for 12 months does not affect total hip, total body, or vertebral BMD when compared with calcium 500 mg and vitamin D 200 IU (101604). The validity of these results is limited by a high dropout rate and insufficient power to detect smaller effects. Conversely, another small study in this population shows that taking specific collagen peptides (Fortibone, Gelita AG) in combination with elemental calcium (as calcium lactate) 500 mg and vitamin D3 400 IU daily for 12 months improves trabecular bone mineral content, trabecular volumetric BMD, and cortical volumetric BMD, but not cortical bone mineral content, when compared with a combination tablet containing equivalent doses of elemental calcium (as calcium carbonate) and vitamin D (107453). It is unclear if these effects are due to collagen peptides, other ingredients, or the combination.
• Osteoporosis. It is unclear if oral collagen peptides improve bone mineral density (BMD) in adults with osteoporosis after menopause. Details: In patients with osteoporosis after menopause, clinical research shows that taking collagen peptides 10 grams daily in addition to twice weekly intramuscular calcitonin for 6 months does not improve BMD in the forearm when compared with calcitonin alone (104649). It is unclear if supplementation with collagen peptides improves BMD in the femoral neck or lumbar spine.
• Pressure ulcers. Oral collagen peptides might help to improve ulcer size and healing. Details: A small clinical study in patients with Stage II, III, or IV pressure ulcers shows that taking collagen peptides 5 grams orally three times daily for 8 weeks in addition to standard care improves ulcer size and exudate when compared with placebo and standard care (101612). This study was limited because it only used one scale to assess healing of the pressure ulcer. Another small clinical study in patients with stage II or III pressure ulcers shows that receiving standard care and collagen peptides with high levels of prolyl-hydroxyproline 5 grams twice daily for 16 weeks improves ulcer exudate, healing, and wound size when compared with standard care plus placebo (101620).
• Sarcopenia. Oral collagen peptides might help to increase fat-free mass. However, it is unclear if collagen peptides are more beneficial than other types of protein. Details: A small clinical study in elderly males with sarcopenia shows that taking collagen peptides from type I collagen 15 grams daily for 12 weeks along with three resistance training sessions weekly modestly increases fat-free mass and power when compared with resistance training and placebo (101624). It is unclear if supplementation with collagen peptides is more beneficial than supplementation with protein.
• Sprains. It is unclear if oral collagen peptides improve ankle instability after a previous sprain. Details: A small clinical study in athletes with chronic ankle instability from an ankle sprain shows that taking collagen peptides 5 grams daily for 6 months improves subjective ankle instability when compared with placebo. However, ankle stiffness, which is a more objective measure of ankle instability, is not improved when compared with placebo (101603).
• Tendinopathy. It is unclear if oral collagen peptides improve tendon pain. Details: A small clinical study in patients with Achilles tendinopathy shows that taking a specific collagen peptides supplement (TENDOFORTE, Gelita AG) 2.5 grams daily for 3 months in addition to a calf-strengthening program improves pain when compared with baseline (101615). The validity of this finding is limited by the lack of a comparator group.
• Wound healing. It is unclear if oral collagen peptides improve wound healing. Details: A small clinical study in healthy volunteers with wounds after photothermolysis shows that taking collagen peptides 3 grams daily for 4 weeks improves erythema, skin hydration, and skin elasticity when compared with placebo (101599). This study was limited by small size, short duration, and no direct measurement of wound healing or scar formation.
• Wrinkled skin. Some small clinical studies suggest that oral collagen peptides might help to reduce lines and wrinkles from sun damage. Details: Preliminary clinical research in females with photodamaged skin shows that taking a specific low molecular weight collagen peptide product (Evercollagen, Newtree Co.) 1000 mg daily for 12 weeks modestly improves most measures of skin wrinkling, hydration, and elasticity when compared with placebo. This specific collagen peptide product is standardized to contain more than 15% glycine-containing tripeptides, including 3% glycyl-prolyl-hydroxyproline (100702). Another moderate-sized clinical study in adults with dry and wrinkled eye skin shows that taking low-molecular weight collagen peptides (GPVGPS Collagen, Daehan Chemtech) 2000 mg daily for 12 weeks reduces skin wrinkling parameters including facial skin roughness, peak-to-valley values, maximum wrinkle height, and eye wrinkle volume and improves skin hydration and skin elasticity when compared with placebo. However, there was no improvement in maximum wrinkle depth (112458). Another preliminary clinical study shows that taking a specific combination product (BioCell Collagen, BioCell Technology, LLC) containing collagen peptides from chicken collagen type II 600 mg, low molecular weight hyaluronic acid 100 mg, and chondroitin sulfate 200 mg daily for 12 weeks reduces lines and wrinkles associated with both natural aging and photoaging by about 13% when compared to baseline (28681). This study was limited by the lack of a comparator group. Additionally, it is unclear if these effects are due to collagen peptides, other ingredients, or the combination. More evidence is needed to rate collagen peptides for these uses.

(Read more about COLLAGEN PEPTIDES)

POSSIBLY EFFECTIVE

• Dry eye. Applying eye drops containing hyaluronic acid alone or in combination with other ingredients, seems to improve symptoms of dry eye. Details: A large meta-analysis of clinical studies in patients with dry eye disease shows that using eye drops containing hyaluronic acid 0.1% to 0.4% for at least 14 days modestly improves tear production when compared with artificial tears or saline control, with a more significant improvement when compared with saline control. Tear stability is also modestly improved when compared with saline control (108622). Several individual clinical studies using specific hyaluronic acid eye drops have also demonstrated improvement. One clinical study in patients with dry eye disease shows that applying eye drops containing hyaluronic acid 0.1% to 0.3% 5-6 times daily for 12 weeks might improve symptoms to a similar degree as cyclosporine 0.05% eye drops. The products used in this study included Hyalein ophthalmic solution 0.1%, New Hyaluni ophthalmic solution 0.15%, and Hyaluni ophthalmic solution 0.3% (97885). Another clinical study shows similar efficacy between hyaluronic acid 0.15% eye drops (New Hyaluni), applied 6 times daily for 12 weeks, and eye drops containing cyclosporine 0.05% and carboxymethylcellulose 0.5%, applied twice daily (110555). A smaller clinical study in patients with dry eye disease shows that applying specific eye drops containing hyaluronic acid 0.2% (Hyalistil) seems to have similar efficacy as using tamarind seed polysaccharide eye drops (16301). Furthermore, adding hyaluronic acid to conventional treatment seems to offer additional benefit. A large multicenter clinical trial in patients with dry eye disease shows that applying 1-2 drops of artificial tears containing carboxymethylcellulose 0.5% and hyaluronic acid 0.1% (Optive Fusion, Allergan) at least 2 times daily for 3 months seems to further improve pain and discomfort when compared with using artificial tears containing carboxymethylcellulose alone (104384). One small clinical study also shows that hyaluronic acid 0.3% ocular gel and hyaluronic acid 0.18% eye drops, applied 4-6 times daily for 12 weeks, are equally effective for improving dry eye symptoms (110556). Hyaluronic acid has also been studied in combination with other ingredients. Several small clinical studies in patients with dry eye syndrome ranging from mild to severe shows that applying eye drops containing hyaluronic acid 0.2% or 0.3%, polyvinylpyrrolidone, and glycerin (Visaid 0.2% or 0.3%, Avizor S.A.), administered as one drop 3-8 times daily for one month, improves some signs and symptoms of dry eye when compared with sodium chloride 0.9% (97894,97895). Conversely, a large clinical study in patients with mild to moderate dry eye disease shows that applying preservative-free eye drops containing sodium hyaluronate with chondroitin sulfate (Humylub Ofteno PF, Laboratorios Sophia), one drop into each eye four times daily for 90 days, seems to be no different for improving dry eye severity when compared with using polyethylene/propylene glycol eye drops (104443).
• Venous leg ulcers. Topical application of hyaluronic acid-impregnated gauze reduces wound size and promotes wound healing. Details: Clinical studies in patients with at least one leg ulcer of venous or mixed arterial/venous origin show that once daily application of a specific hyaluronic acid-impregnated gauze (Ialuset, Laboratoires Genévrier) reduces wound size at 45 days by 73% and produces complete wound healing at or before 20 weeks in 40% of patients. In those receiving a neutral vehicle gauze, these improvements occurred in 46% and 19% of patients, respectively (108627,108640).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Aging skin. Oral hyaluronic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. It is also unclear if topical hyaluronic acid is beneficial for aging skin. Details: A very small study shows that taking a specific combination product (GliSODin Skin Nutrients Advanced Anti-Aging Formula, Isocell North America Inc.) containing hyaluronic acid, krill oil, sea buckthorn berry oil, and cacao bean extract orally three times daily for 90 days, along with applying tazarotene 0.1% cream, moderately decreases wrinkling and photodamage and improves skin moisture and elasticity when compared with tazarotene cream alone (91778). Another small clinical study in females with aging skin shows that taking a specific combination product (BioCell Collagen, BioCell Technology, LLC) containing hyaluronic acid 100 mg, chondroitin sulfate 200 mg, and collagen peptides 600 mg daily for 12 weeks reduces lines and wrinkles by about 13% when compared with baseline (28681). The validity of this finding is limited by the lack of a comparator group. Furthermore, it should be noted that both studies were funded by the product manufacturer. A small open-label clinical study in females with mild to moderate lip dryness and mild to severe lip condition shows that three daily applications of a two-step lip treatment containing hyaluronic acid for 4 weeks improves the overall condition of lips, as well as texture/visual roughness, plumpness, color/rosiness, definition/contour, and lines/wrinkles when compared with baseline (108634). The validity of these findings is limited by the lack of a comparator group.
• Allergic rhinitis (hay fever). It is unclear if nasal irrigation with sodium hyaluronate is beneficial in patients with mild, persistent seasonal allergic rhinitis. Details: A small clinical study in patients with mild, persistent seasonal allergic rhinitis receiving an oral antihistamine and an intranasal corticosteroid shows that nasal irrigation with sodium hyaluronate twice daily for 1 month improves mucociliary clearance time by 3 minutes, compared with 1 minute with the use of isotonic saline and 5 minutes with the use of surfactant (108630). It is unclear if this change is associated with clinically relevant symptom improvement.
• Burns. It is unclear if topical hyaluronic acid is beneficial in patients with burns. Details: A meta-analysis of small clinical trials suggests that topical hyaluronic acid and hyaluronic acid derivatives might improve the healing of wounds, including burns, when compared with control (104389). A small nonrandomized clinical study in patients with partial- to full-thickness burns shows that hyaluronic acid 0.2% gel daily for 12 weeks during the re-epithelialization phase reduces erythema, tension, pruritus, burning, and neoangiogenesis when compared with baseline (108636). The lack of statistical comparison to the ozonated oil group and the single-blinded nature of the study limit the validity of these findings.
• Canker sores. It is unclear if topical hyaluronic acid is beneficial for canker sores. Details: A clinical study in adults with recurrent canker sores shows that applying a gel containing hyaluronic acid 0.2% two to three times daily for 7 days reduces soreness immediately and for up to 30 minutes after application when compared with baseline. However, these improvements are numerically similar to those seen with placebo (108637). The lack of statistical comparison to placebo limits the validity of this finding. A small observational study in children with recurrent canker sores has found that applying a gel containing hyaluronic acid 0.2% twice daily for 7 days is similarly effective to dexamethasone topical ointment applied three times daily for 5 days for reducing pain and ulcer size (104388).
• Corneal abrasion. It is unclear if eye drops containing hyaluronic acid are beneficial in preventing recurrence in patients with a history of traumatic corneal abrasion. Details: A small clinical study in patients with fully healed traumatic corneal abrasion at risk for recurrence shows that administration of eye drops containing hyaluronic acid 0.3% five times daily for 3 months does not reduce the incidence rate of major symptomatic episodes at 12 months when compared with observation alone (108623).
• Diabetic foot ulcers. Oral hyaluronic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A meta-analysis of results from 4 clinical studies shows that applying hyaluronic acid combination gels or hyaluronic acid-based biomaterials to diabetic foot ulcers increases the odds of complete healing at 12 weeks by about 1.7-fold when compared to control treatment. Forms of hyaluronic acid assessed in the evaluated studies included zinc hyaluronate, hyaluronic acid-based biomaterial (Hyalograft 3D autograft), and a gel containing hyaluronic acid and amino acids (Vulnamin Gel, Errekappa) (91776). It is not clear if the beneficial effects were due to hyaluronic acid or other components of the treatments.
• Exercise-induced muscle soreness. Oral hyaluronic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in healthy, recreationally active adults shows that a specific product (BioCell Collagen, BioCell Technology, LLC) containing hyaluronic acid 150 mg, chondroitin sulfate 300 mg, and collagen peptides 900 mg, taken twice daily for 6 weeks prior to two bouts of resistance exercise, attenuates muscle damage and decreases delayed-onset muscle soreness when compared with placebo (96301). It is unclear if these effects are due to hyaluronic acid, the other ingredients, or the combination. Furthermore, it should be noted that both studies were funded by the product manufacturer.
• Gastroesophageal reflux disease (GERD). Oral hyaluronic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Patients with non-erosive GERD are thought to be less responsive to conventional acid suppression with proton pump inhibiters (PPIs) and H-2 blockers. A small preliminary clinical study shows that taking a syrup containing hyaluronic acid and chondroitin sulfate along with PPIs, H2-receptor antagonists, and/or antacids, reduces the intensity of symptoms associated with non-erosive GERD by about 3.5-fold when compared with placebo (89592). A larger clinical study in patients with non-erosive GERD shows that taking a different formulation of the same combination of chondroitin sulfate and hyaluronic acid (Esoxx, Alfa Wassermann) 4 times daily for 14 days, in conjunction with a PPI, improves GERD symptom severity by 21%, heartburn by 15%, and regurgitation by 10% when compared with using a PPI and placebo (101271). Hyaluronic acid has also been evaluated in combination with chondroitin sulfate in patients with extraesophageal symptoms of GERD. A small, open-label study shows that taking a specific combination product (Gerdoff, SOFAR S.p.A.) containing hyaluronic acid and chondroitin sulfate three times daily with omeprazole 40 mg daily for 6 weeks increases the rate of treatment response, defined as a 50% or greater improvement in reflux symptoms index scores, by around 40% when compared with omeprazole alone. While average symptom scores were not significantly improved with the combination product over omeprazole, the need for omeprazole as rescue therapy for breakthrough symptoms was reduced in the treatment group (109648). It is unclear if the findings described above are due to hyaluronic acid, chondroitin sulfate, or the combination.
• Gingivitis. It is unclear if hyaluronic acid used in a mouthwash reduces gingivitis severity. Details: A small clinical study in patients with biofilm-induced gingivitis shows that rinsing with 10 mL of hyaluronic acid 0.025% mouth wash (Gengigel, RICERFARMA SRL) for 1 minute twice daily reduces probing index and bleeding when compared with rinsing with a placebo solution, but is less effective when compared with chlorhexidine 0.12% solution (104383). Another small clinical study in patients with plaque-induced gingivitis shows that rinsing with 10 mL of a mouthwash containing hyaluronic acid 0.1% and hydrogen peroxide 1.8% for 30 seconds twice daily for 21 days reduces gingival index scores but not plaque index scores when compared with placebo (110554). It is unclear if these findings are due to hyaluronic acid, hydrogen peroxide, or the combination.
• Intranasal surgery. It is unclear if topical hyaluronic acid irrigation improves recovery in patients after nasal surgery. Details: A small clinical study in patients that underwent nasal surgery for chronic rhinosinusitis shows that performing nasal irrigation with high molecular weight sodium hyaluronate 9 mg twice daily for 6 weeks improves sinus scarring, crusting, and headache when compared with nasal irrigation with saline. However, the sodium hyaluronate irrigation did not improve sinus inflammation or secretions, nasal obstruction, or facial pain (101288).
• Intrauterine adhesions. Several small studies suggest that intrauterine administration of hyaluronic acid gel seems to prevent intrauterine adhesions after uterine surgery. Details: Meta-analyses of 11-12 small clinical studies in patients undergoing uterine surgery shows that intrauterine application of 1-10 mL of hyaluronic acid gel after surgery reduces the risk of intrauterine adhesions by around 50% and increases pregnancy rates when compared with no treatment (110551,110552). One analysis suggests that hyaluronic acid is most effective for prevention of intrauterine adhesions when at least 5 mL of gel is applied (110551).
• Lichen planus. It is unclear if topical hyaluronic acid is beneficial in patients with oral lichen planus. Details: A clinical study in patients with oral lichen planus shows that application of a gel containing hyaluronic acid 0.2% four to five times daily for 28 days reduces soreness in as little as 5 minutes for up to 4 hours when compared with baseline. These findings are numerically similar to those seen with placebo; however, the lack of statistical comparison to placebo limits the validity of this finding (108635). A small clinical study in patients with symptomatic oral lichen planus (including mixed forms) shows that application of a gel containing hyaluronic acid 0.2% three times daily for 4 weeks is similarly effective to triamcinolone for improving pain, erythema, and lesion size (108633). It is unclear if the improvement from baseline differed between groups.
• Melasma. It is unclear if topical hyaluronic acid is beneficial in patients with moderate to severe facial melasma. Details: A small clinical study in patients with mostly mixed-type, moderate to severe facial melasma shows that twice daily application of hyaluronic acid along with isobutylamido thiazolyl resorcinol reduces melasma severity similarly to isobutylamido thiazolyl resorcinol alone (108628). The single-blinded nature of the study limits the validity of these findings.
• Oral mucositis. Topical hyaluronic acid has only been evaluated in combination with other ingredients; its effects when used alone is unclear. Details: A small clinical study in children aged 5 years or older with chemotherapy-induced oral mucositis shows that using a solution containing sodium hyaluronate, verbascoside, and polyvinylpyrrolidone (Mucosyte; Biopharm) three times daily is more effective than placebo for improving pain and other symptoms (97890). Another small clinical study in adults in recovery from hematopoietic stem cell transplantation shows that using a spray product containing sodium hyaluronate with synthetic amino acid precursors of collagen (Mucosamin) attenuates the development of severe oral mucositis when compared with chlorhexidine 0.2% (97889).
• Osteoarthritis. It is unclear if oral hyaluronic acid is beneficial in patients with osteoarthritis of the knee. Details: A small study in patients with knee osteoarthritis shows that taking chicken comb extract (Hyal-Joint, Bioibérica) 80 mg, standardized to contain hyaluronic acid 60% to 70%, once daily for 8 weeks does not reduce pain when compared with placebo (55742). This study was limited by small size and a significant placebo effect. Another small study in patients with knee osteoarthritis shows that taking a different supplement (Oralvisc, Bioibérica) 80 mg standardized to contain hyaluronic acid 70% and glycosaminoglycans once daily for 3 months modestly reduces pain when compared with placebo (91779). Reasons for these differing findings may relate to hyaluronic acid formulation, study funding sources, or the magnitude of placebo effect. Hyaluronic acid has also been studied in combination with chondroitin and collagen peptides (BioCell Collagen, BioCell Technology, LLC) with some evidence of benefit (28680).
• Otitis media. It is unclear if using intranasal hyaluronic acid solution is beneficial for otitis media in children. Details: Preliminary clinical research in children 3-12 years of age who have recurrent or chronic middle ear inflammation and adenoiditis shows that using a compound (Yabro, IBSA Farmaceutici Italia S.r.l.) containing hyaluronic acid in saline intranasally 15 days per month for 3 months modestly reduces the number of patients with impaired otoscopy or middle ear function when compared to baseline (97888). It is unclear if this effect is due to the hyaluronic acid product or to the natural resolution of inflammation over time.
• Radiation dermatitis. It is unclear if topical hyaluronic acid is beneficial for the prevention of radiation dermatitis. Details: A small clinical study in patients with breast cancer undergoing adjuvant radiation therapy following lumpectomy shows that three daily applications of a specific hyaluronic acid gel (RadiaPlex, MPM Medical) to one side of the breast results in a grade 2 or greater dermatitis occurrence rate of 62%, compared with a rate of 48% on the side receiving petrolatum-based gel. A review of a planned interim analysis led to early trial discontinuation (108638).
• Rhinosinusitis. It is unclear if hyaluronic acid solution is beneficial for acute or chronic rhinosinusitis when used in an intranasal saline rinse. Details: A small clinical study in adults with acute rhinosinusitis who are being treated with levofloxacin and prednisone shows that using a 3% hyaluronic acid in saline nasal douche twice daily improves smell, obstruction, and discharge within 14 days when compared with saline alone (97886). A very small clinical study in patients with chronic rhinosinusitis without nasal polyps shows that receiving micronized nasal hyaluronic acid douches twice daily for 30 days improves nasal symptoms, nasal obstruction, and ability to smell to a similar degree as normal saline (104387).
• Sexual dysfunction. It is unclear if vaginal hyaluronic acid is beneficial for improving sexual function in adults with dyspareunia. Details: A small nonrandomized clinical study in females with dyspareunia while taking oral hormonal contraceptives shows that once daily vaginal application of a hyaluronic acid gel for 12 weeks reduces pain and improves sexual function at 12 weeks when compared baseline. Though patients treated with twice weekly vaginal estrogen therapy had better 12-week scores than patients treated with hyaluronic acid, it is unclear if the improvements from baseline differed between groups (108639).
• Tooth extraction. It is unclear if topical hyaluronic acid is beneficial for wound healing after tooth extraction. Details: A small clinical study in patients undergoing tooth extraction shows that application of hyaluronic acid 0.2% gel or hyaluronic acid 0.1% spray to the extraction socket twice daily for 7 days increases the rate of wound closure when compared with no treatment (110553). The validity of these findings is limited by a lack of placebo control group.
• Urinary tract infections (UTIs). Oral and intravesical hyaluronic acid have been evaluated for the prevention of UTI in combination with other ingredients; its effect when used alone is unclear. Details: A meta-analysis of prospective and retrospective studies shows that intravesical administration of 50 mL of specific solutions containing chondroitin sulfate 2% and hyaluronic acid 1.6% (iAluRil, IBSA Farmaceutici; Cystistat, Bioniche), once weekly to once monthly for up to 6 months, reduces the rate of UTI recurrence by about 2-3 incidents per year and delays the time to the first UTI recurrence when compared with placebo or prophylaxis with sulfamethoxazole-trimethoprim (99688). However, the validity of these findings is limited by the low quality and high heterogeneity of the included studies, as well as concerns for publication bias. Also, the effect of hyaluronic acid alone is unclear. Oral hyaluronic acid has also been evaluated in combination with other ingredients for the prevention of recurrent UTI. A small prospective observational study shows that taking 1-2 capsules of a combination of hyaluronic acid, chondroitin sulfate, curcumin, and quercetin daily for 15 days each month, in conjunction with the use of local topical estrogen therapy for up to 12 months, reduces the number of women with recurrent UTIs when compared with taking the oral combination product or the vaginal estrogen product alone (96781). It is unclear if this effect is due to hyaluronic acid, other ingredients, or the combination.
• Vaginal atrophy. It is unclear if topical hyaluronic acid is beneficial for improving symptoms of vaginal atrophy. Details: A small, open-label clinical trial in patients going through menopause with symptoms of vaginal atrophy shows that applying 3 grams of a topical vaginal preparation of hyaluronic acid (Hyalo Gyn, Fidia Farmaceutici) every 3 days for 30 days improves vaginal health scores and reduces vaginal itching, vaginal burning, and pain during intercourse when compared to baseline. However, it does not appear to be any more effective than a polycarbophil vaginal gel (110549). Also, a small observational study in postmenopausal patients with vulvovaginal atrophy has found that applying a topical vaginal preparation containing hyaluronic acid (Justgin, JustPharma) three times weekly for 8 weeks is associated with improved symptoms of vaginal dryness, burning, and itching, as well as pain during intercourse, when compared to baseline (97887). The validity of these findings is limited by the lack of a comparator group and retrospective nature of the study. Some research has evaluated combination products containing hyaluronic acid for vaginal atrophy. A clinical trial in patients with cervical cancer shows that intravaginal administration of a specific suppository (Santes, Lo.Li. Pharma) containing hyaluronic acid, vitamin E, and vitamin A, once daily for the 5 week duration of radiotherapy reduces vaginal dryness, inflammation, and dyspareunia when compared with no additional treatment (101283). Also, a small, open-label clinical study in patients with vaginal atrophy after treatment for breast cancer shows that intravaginal application of a suppository containing hyaluronic acid and extract of aloe, marigold, tiger grass, and tea tree daily for 10 days then every 3 days for 80 days improves vaginal health scores and reduces vaginal dryness and pain during intercourse when compared to baseline, with no difference between the hyaluronic acid-containing suppository and vaginal laser therapy (110550). It is unclear if these findings are due to hyaluronic acid, other ingredients, or the combination.
• Wound healing. Small clinical studies show that topical hyaluronic acid and hyaluronic acid derivatives may improve the healing of various types of wounds. Details: A meta-analysis of small clinical trials suggest that topical hyaluronic acid and hyaluronic acid derivatives might improve the healing of burns, wounds, and skin ulcers when compared with control (104389). More evidence is needed to rate hyaluronic acid for these uses.

(Read more about HYALURONIC ACID)

LIKELY INEFFECTIVE

• Cancer. Most clinical research shows that oral shark cartilage is not beneficial in people with advanced cancer. Details: Most clinical research shows that taking shark cartilage orally offers no benefit in people with advanced, previously-treated cancer, including breast, colorectal, lung, prostate, and brain cancers, and non-Hodgkin's lymphoma (2015,6716,6717,13086,17102,74731). These studies used shark cartilage powder (Cartilade, Cartilage USA; Benefin, Lane Labs) at doses of 1-1.3 grams/kg daily or 96 grams daily (2015,6717,13086) and shark cartilage extract (AE-941, Neovastat) (17102). Studies of shark cartilage in less advanced cancer have not been published.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Age-related macular degeneration (AMD). Although there is interest in using oral shark cartilage for AMD, there is insufficient reliable information about the clinical effects of shark cartilage for this condition.
• Diabetic retinopathy. Although there is interest in using oral shark cartilage for diabetic retinopathy, there is insufficient reliable information about the clinical effects of shark cartilage for this condition.
• Kaposi sarcoma. It is unclear if oral shark cartilage is beneficial in patients with Kaposi sarcoma. Details: There is anecdotal evidence that taking shark cartilage orally, 3.75-4.5 grams daily divided into 3 doses, might decrease cutaneous Kaposi sarcoma lesions and increase histological regression (4938). Prospective clinical research is needed to confirm this finding.
• Osteoarthritis. Topical shark cartilage has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that applying a topical preparation of shark cartilage 140 mg, chondroitin sulfate 50 mg, glucosamine sulfate 30 mg, and camphor 32 mg per gram, as needed for up to 8 weeks, reduces osteoarthritis symptoms. However, any symptom relief is most likely due to the counterirritant effect of camphor and not the other ingredients (10327).
• Psoriasis. It is unclear if topical shark cartilage is beneficial in patients with psoriasis. Details: Preliminary clinical research in adults with plaque psoriasis shows that applying a specific solution of a shark cartilage extract (AE-941, Neovastat) topically, 30-240 mL to affected areas daily for up to 12 weeks, can improve the appearance of plaques and reduce itching when compared with baseline (4893,10399).
• Renal cell carcinoma. It is unclear if oral shark cartilage is beneficial in patients with renal cell carcinoma. Details: Preliminary clinical research shows that taking a specific solution of shark cartilage extract (AE-941, Neovastat), 60-240 mL daily orally, seems to increase survival in patients with advanced renal cell carcinoma (4894,10900). However, no further clinical evidence has been published, and this specific extract is no longer being evaluated for the treatment of renal cell carcinoma.
• Rheumatoid arthritis (RA). Although there is interest in using oral shark cartilage for RA, there is insufficient reliable information about the clinical effects of shark cartilage for this condition. More evidence is needed to rate shark cartilage for these uses.

(Read more about SHARK CARTILAGE)

LIKELY EFFECTIVE

• Cystic fibrosis. Long-term nebulized hypertonic sodium chloride improves lung function and reduces pulmonary exacerbations in patients with cystic fibrosis. Details: Meta-analyses of clinical research in adults with cystic fibrosis show that, when taken along with a bronchodilator and other standard therapies, nebulized hypertonic sodium chloride in concentrations of 3% to 7%, up to 10 mL twice daily for 4 weeks, increases forced expiratory volume at one second (FEV1) when compared with isotonic saline (sodium chloride 0.9%) (26230,26230). This benefit was not seen at 48 weeks. Other clinical research in adults with cystic fibrosis shows that inhaling sodium chloride 7%, 4 mL twice daily for 48 weeks, does not improve FEV1 when compared with isotonic saline. However, chronic treatment with hypertonic saline does reduce the number of pulmonary exacerbations and increase the number of patients without pulmonary exacerbations when compared with isotonic saline (29402). It is not clear if this benefit occurs in children with cystic fibrosis. The Pulmonary Clinical Practice Guidelines Committee of the Cystic Fibrosis Foundation recommends that individuals with cystic fibrosis aged 6 years or older use nebulized hypertonic saline long-term to improve lung function, reduce the number of exacerbations, and improve quality of life (29403).

POSSIBLY EFFECTIVE

• Amphotericin B nephrotoxicity. Oral sodium chloride seems to prevent nephrotoxicity associated with use of amphotericin B. Details: Clinical research shows that administering oral or intravenous sodium chloride 150 mEq daily during treatment with amphotericin B can attenuate the rise in serum creatinine levels and preserve renal function when compared to treatment with amphotericin B alone (26226).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Bipolar disorder. It is unclear if oral sodium is beneficial in preventing lithium level fluctuations in patients with bipolar disorder. Details: A moderate-sized open-label clinical study in adults with type I bipolar disorder receiving lithium carbonate shows that taking sodium chloride 1 gram daily for 12 weeks along with dietary salt restriction of 1 gram daily reduces the percentage of patients with lithium level fluctuations above 0.8 mEq/L, but does not significantly affect serum sodium, potassium, aldosterone, or creatinine levels when compared with controls who were not salt restricted, but were advised not to consume additional salt at the table (112909). However, the interpretation of these findings is limited by missing data in both groups.
• Canker sores. Although there is interest in using topical sodium chloride for canker sores, there is insufficient reliable information about the clinical effects of sodium chloride for this condition.
• Congestive heart failure. It is unclear if oral sodium is beneficial in patients with acute decompensated heart failure requiring decongestive therapy with diuretics. Details: A moderate-sized clinical study in adults hospitalized with acute decompensated heart failure requiring high-dose intravenous furosemide shows that taking sodium chloride 2 grams three times daily for up to 96 hours does not affect patient weight or serum creatinine levels when compared with placebo (112911). However, the clinical relevance of this study is unclear and it may have been inadequately powered to detect a difference between groups.
• Conjunctivitis. Although there is interest in using ophthalmic sodium chloride for conjunctivitis, there is insufficient reliable information about the clinical effects of sodium chloride for this condition.
• Hyponatremia. Although there is interest in using oral sodium chloride for hyponatremia, there is insufficient reliable information about the clinical effects of oral sodium chloride for this condition.
• Pharyngitis. Although there is interest in using topical sodium chloride for pharyngitis, there is insufficient reliable information about the clinical effects of sodium chloride for this condition.
• Prematurity. It is unclear if oral sodium is beneficial for premature infants. Details: Preliminary clinical research in infants born at less than 32 weeks' gestation shows that adding sodium 4 mEq/kg daily to enteral feedings, starting from the 7th day after birth and continuing through the 35th day, reduces the risk of developing hyponatremia and improves weight gain when compared with adding water (98180). A small, open-label clinical study in newborns less than 35 weeks gestation shows that high sodium intake, defined as an average of 0.25% sodium in maintenance fluids, for 48 hours on day 2 and 3 after birth results in less weight loss within the first 72 hours of life when compared with control, but does not improve mortality, length of hospital stay, or complications from prematurity (112908). However, interpretation of these findings is limited by varied concentrations of sodium as an intervention. More evidence is needed to rate sodium for these uses.

(Read more about SODIUM)

EFFECTIVE

• Imerslund-Grasbeck disease. Intramuscular vitamin B12 is effective for patients with this condition. Details: Administering intramuscular vitamin B12 (hydroxocobalamin) 1 mg daily for 10 days, followed by monthly injections for the remainder of a patient's life, is effective for treating familial selective vitamin B12 malabsorption (Imerslund-Grasbeck disease) (15,82862).
• Vitamin B12 deficiency. Administering vitamin B12 orally, intramuscularly, or intranasally is effective for preventing and treating vitamin B12 deficiency. Details: Vitamin B12 deficiency has varying definitions but is often defined as vitamin B12 (cobalamin) levels less than 180-200 pmol/L (or 240 pg/mL). Some believe that only intramuscular vitamin B12 is effective for treating vitamin B12 deficiency. However, clinical research shows that oral therapy increases cobalamin levels similarly to intramuscular administration, even in patients with pernicious anemia or malabsorption, if a high enough dose is given (2909,2911,2915,9335,82832) (82836,82949,82860,103976,103972,107141,107144). Some evidence suggests that the most effective oral dose is between 647-1032 mcg daily (13106). However, in certain situations, intramuscular treatment might be more appropriate. Guidelines by the British Committee for Standards in Hematology recommend only intramuscular vitamin B12 for initial treatment of severe vitamin B12 deficiency in patients with pernicious anemia, malabsorption disorders, or neurological involvement (94722). Intramuscular vitamin B12 is also appropriate in patients with diarrhea or vomiting and those likely to be nonadherent (103972). Vitamin B12 deficiency is especially common in older adults, primarily due to lack of intrinsic factor and malabsorption (2915,2919,9335). Daily supplementation with vitamin B12 50-100 mcg might be needed to correct deficiency (10126), while daily doses of 25-37.5 mcg help to maintain normal levels over time (9335). In addition to supplements, foods such as milk and bread fortified with vitamin B12 can be used and are approximately 55% to 60% absorbed by people over 60 years of age (10124). Vitamin B12 deficiency is also common in patients that have had gastric surgery, including gastrectomy and bariatric surgery (107144,107145). Taking vitamin B12 in the doses found in multivitamins or generic vitamin B supplements does not seem to prevent vitamin B12 deficiency following bariatric surgery (107145). However, taking methylcobalamin 500 mcg daily is beneficial for treating vitamin B12 deficiency associated with a total gastrectomy and taking cyanocobalamin 5000 mcg daily is beneficial for preventing vitamin B12 deficiency following gastric bypass (107144). Other people at risk for vitamin B12 deficiency include strict vegetarians who eat no animal products (vegans) and people with increased vitamin B12 requirements associated with pregnancy, thyrotoxicosis, hemolytic anemia, hemorrhage, malignancy, and hepatic and kidney disease. Moderate consumption of animal products may not be sufficient to restore and maintain vitamin B12 levels, especially in adolescents who had consumed macrobiotic (vegan type) diets for the first 6 years of life. High dietary intake of vitamin B12 or supplements is usually needed in order to restore and maintain optimal vitamin B12 levels in these adolescents (10125).

LIKELY EFFECTIVE

• Cyanide poisoning. Intravenous hydroxocobalamin (Cyanokit) is likely effective as an antidote for patients with suspected or known cyanide toxicity due to inhalation, ingestion, or skin exposure. Details: Treatment of cyanide poisoning with hydroxocobalamin (Cyanokit) up to 10 grams has been approved by the US Food and Drug Administration (FDA) and recommended by the Australian Resuscitation Council (82870,82905,82906). Hydroxocobalamin is also FDA-approved for treating cyanide toxicity during pregnancy (82904).

POSSIBLY EFFECTIVE

• Canker sores. Sublingual or topical vitamin B12 seems to reduce canker sore symptoms. Details: Clinical research in patients with canker sores shows that applying a topical ointment containing vitamin B12 500 mcg in four divided doses daily for 2 days reduces pain levels by 80% when compared with a control ointment not containing vitamin B12 (96176). Other preliminary clinical research shows that taking vitamin B12 1000 mcg sublingually daily for 6 months reduces the duration of canker sore outbreaks, the number of ulcers, and level of pain when compared with placebo in patients with normal vitamin B12 levels (17242).
• Hyperhomocysteinemia. Oral vitamin B12 in combination with folic acid, and sometimes with vitamin B6, reduces homocysteine levels. Details: While folic acid 0.5-5 mg daily lowers fasting homocysteine levels by an average of 25%, adding vitamin B12 0.5 mg daily produces an additional decrease of about 7% on average (6883,9400,9401,9405,9409,50145,107136). Vitamin B12 in combination with folic acid and other vitamins also reduces homocysteine levels in patients with kidney failure, sickle cell disease, and those receiving nitrous oxide general anesthesia (1489,6883,6884,7289,7881,9324,9414,9415,9416,9481,82941). Some researchers recommend routine use of vitamin B12 with homocysteine-lowering regimens to avoid the risk of neuropathy in people with undetected vitamin B12 deficiency (9405). Using vitamin B12 alone has a limited effect on homocysteine levels, and probably only in those people with vitamin B12 deficiency (2147,9410,9512). Hyperhomocysteinemia is considered by some to be an independent risk factor for atherosclerosis, recurrent thromboembolism, deep vein thrombosis, myocardial infarction, and ischemic stroke (1899,2147,3323,9402,9405,9408,9409). Clinical research suggests that supplementation with folic acid, pyridoxine, and vitamin B12 decreases homocysteine levels and reduces the atherosclerosis progression in patients at risk for atherosclerosis when compared with placebo (50133,50056,82806). However, other research suggests that elevated homocysteine levels may be a marker, as opposed to a cause, of vascular disease (11387,11388). A 5 µmol/L increase in plasma homocysteine increases the risk of cerebrovascular disease by 50%, and the odds of coronary heart disease by 60% and 80% in males and females, respectively (9407,9411). However, it is not clear if reducing homocysteine levels results in reduced cardiovascular morbidity and mortality (1489,6883,6884,9400,9405,9409,96417). Folic acid, vitamin B6, and vitamin B12 supplementation can reduce total homocysteine from 13.4 to 11 µmol/L. However, this reduction does not seem improve endothelial function or help with secondary prevention of death or myocardial infarction, and some research even suggests an increase in cardiovascular disease (CVD) risk (11387,13482,50373,50314,97619). There is also some debate about whether supplementation with homocysteine-lowering B vitamins can reduce the risk of stroke. A number of large clinical studies and meta-analyses show that supplementation with folic acid, vitamin B6, and vitamin B12, alone or in combination, does not reduce the risk of stroke in patients with CVD or impaired kidney function (11387,13482,50423,83050,96150). However, a more recent meta-analysis of 10 clinical trials including over 44,000 patients shows that B vitamin supplementation reduces the relative risk of stroke by 10% when compared with placebo in patients at risk or with a history of CVD (97619). Also, a meta-analysis in adults with a history of stroke shows that B vitamin supplementation modestly reduces the relative risk of stroke recurrence by 13% and vascular death by 11% when compared with placebo (107136).
• Postherpetic neuralgia. Subcutaneous injections of vitamin B12 seem to reduce postherpetic neuralgia symptoms. Details: Clinical research in patients with subacute herpetic neuralgia shows that subcutaneous injection of vitamin B12 (methylcobalamin) 1000 mcg six times weekly for 4 weeks reduces pain when compared with oral vitamin B12 or subcutaneous lidocaine (90394). Another clinical study shows that administering local subcutaneous injections of methylcobalamin 1000 mcg plus lidocaine up to 20 mg daily for 12 injections over 14 days, starting within 7 days of the onset of subacute ophthalmic herpetic neuralgia, decreases the mean pain score by 63% to 79% when compared with intravenous lidocaine and intramuscular methylcobalamin. Less than 2 patients need to be treated to achieve a pain reduction to ≤3 out of 10. Healing of rash, itching, numbness, and tingling were also improved (96175). Additional clinical research in patients with postherpetic pain and itching shows that this same dosing regimen of subcutaneous vitamin B12 reduces pain and analgesic requirements when compared to baseline (90396).

POSSIBLY INEFFECTIVE

• Age-related cognitive decline. Oral vitamin B12 does not seem to improve cognitive function in older adults when used alone or in combination with other B vitamins. Details: Taking vitamin B12 100-1000 mcg plus folic acid 400-2000 mcg, with or without vitamin B6 3-50 mg, daily for up to about 2 years does not seem to improve tests of cognitive function in adults aged 65 or older, most of whom do not report cognitive impairment at baseline (14392,50225,50510,90392,107140). Also, supplementation with vitamin B12 does not seem to improve cognitive function in elderly individuals with low vitamin B12 levels (12305).
• Alzheimer disease. Oral vitamin B12, when used in combination with other B vitamins, does not seem to improve cognitive function in patients with Alzheimer disease. Details: Clinical research in patients with probable Alzheimer disease using routine medication shows that taking vitamin B12 1 mg, folic acid 5 mg, and vitamin B6 25 mg daily for 18 months does not have a beneficial effect on cognitive function or the severity of disease when compared with placebo. In this study, all patients were consuming a folate-fortified diet (50319). Also, a meta-analysis of clinical research in elderly adults with mild cognitive impairment or dementia shows that taking vitamin B12, usually with other B vitamins, does not improve cognitive function (50510). Observational research has also found that higher vitamin B12 intake over 3 years in a population consuming a folate-fortified diet is not associated with a decreased risk of developing Alzheimer disease (15270). In contrast, preliminary clinical research in patients with probable Alzheimer disease who are not consuming a folate-fortified diet shows that taking vitamin B12 50 mcg daily plus folic acid 1.2 mg daily for 6 months modestly improves some measures of cognitive performance and decreases levels of homocysteine when compared with placebo (107150). More research is needed to determine if any changes in this latter study are clinically relevant.
• Cataracts. Oral vitamin B12 does not seem to reduce cataract development. Details: Clinical research in women with existing cardiovascular disease (CVD) or at increased risk of CVD shows that taking a combination of folic acid 2.5 mg daily, vitamin B6 50 mg daily, and vitamin B12 1 mg daily for an average of 7.3 years does not reduce the risk of cataracts and seems to increase the risk of cataract extraction by 28% when compared with placebo (96149).
• Circadian rhythm sleep disorders. Oral vitamin B12 does not seem to improve sleep disorders. Details: Oral vitamin B12 (methylcobalamin) does not seem to be effective for treating delayed sleep phase syndrome. Methylcobalamin 0.5-1 mg three times daily, with or without bright light therapy, also does not seem to help people with primary circadian rhythm sleep disorders (1344,1345,1346,1347,1348).
• Cognitive impairment. Oral vitamin B12 does not seem to be beneficial for older adults with cognitive impairment. Details: A meta-analysis of clinical research in elderly adults with mild cognitive impairment or dementia shows that taking vitamin B12, usually with other B vitamins, does not improve cognitive function (50510). One clinical trial in elderly people with memory complaints shows that taking a combination of B vitamins, including folic acid 0.8 mg, vitamin B12 0.5 mg, and vitamin B6 (form not specified) 20 mg daily for 24 months reduces cerebral atrophy in the gray matter regions associated with Alzheimer disease by up to seven-fold when compared with placebo. However, this protection does not occur in patients with the lowest average blood levels of homocysteine (90374).
• Fall prevention. Oral vitamin B12 does not seem to reduce the risk of falls. Details: Clinical research shows that taking B vitamins, including folic acid 400 mcg and vitamin B12 500 mcg, daily for 2 years does not prevent falls when compared with placebo in elderly individuals also taking vitamin D (96148).
• Osteoporosis. Oral vitamin B12 does not seem to reduce the risk of osteoporotic fractures. Details: Clinical research in elderly patients or patients with a history of cerebrovascular disease shows that taking vitamin B12 500 mcg and folic acid 0.4-2 mg, with or without vitamin B6 25 mg, daily for 2-3 years does not seem to reduce the risk for osteoporotic fractures when compared with placebo (90377,90393). A 5-7 year follow-up of this research has also found no benefit (103981).
• Physical performance. Oral vitamin B12 does not seem to improve physical performance in older adults. Details: Clinical research shows that taking B vitamins, including folic acid 400 mcg and vitamin B12 500 mcg, daily for 2 years does not increase hand strength or improve performance such as walking when compared with placebo in elderly individuals also taking vitamin D (96148).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Age-related macular degeneration (AMD). Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A large-scale clinical study shows that taking vitamin B12 1000 mcg, folic acid 2.5 mg, and vitamin B6 50 mg daily, reduces the risk of developing AMD in females over 40 years of age with a history of cardiovascular disease (CVD) or at least three risk factors for CVD. Those who took this combination for an average of 7.3 years had a 34% reduced risk of developing AMD and a 41% reduced risk of visually significant AMD when compared with placebo (14620). It is unclear if this effect is due to vitamin B12, other ingredients, or the combination.
• Amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease). It is unclear if high-dose intramuscular vitamin B12 improves the prognosis of ALS. Details: A clinical study in patients with ALS symptoms for 3 years or less shows that intramuscular vitamin B12 (methylcobalamin) 25-50 mg twice weekly for 3.5 years does not slow functional decline or increase the time until ventilation or death when compared with placebo. However, other clinical research in patients with early-stage ALS shows that intramuscular methylcobalamin 50 mg twice weekly for 16 weeks is associated with slower functional decline and a longer period of time until death or full ventilation when compared with placebo (104947,111556). These effects seem to be particularly notable in fine and gross motor skills, but not bulbar or respiratory functions. Furthermore, vitamin B12 and riluzole slowed clinical progression of ALS more than riluzole alone (111556).
• Angioplasty. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Some evidence suggests that vitamin B12 400 mcg, folic acid 1 mg, and vitamin B6 10 mg daily can decrease the rate of restenosis in patients treated with balloon angioplasty (8009,9412,34540). However, this combination does not seem to be as effective for reducing restenosis in patients after coronary stenting (8009). An intravenous loading dose of folic acid, pyridoxine, and vitamin B12 followed by oral administration of folic acid 1.2 mg, pyridoxine 48 mg, and vitamin B12 60 mcg daily after bare metal coronary stenting also does not seem to reduce restenosis and might actually increase restenosis (12150,12151,34540). Due to the lack of evidence of benefit and potential for harm, this combination of vitamins should not be recommended for patients receiving coronary stents (12151). It is unclear if any effects are due to vitamin B12, other ingredients, or the combination.
• Anxiety. Although there is interest in using oral vitamin B12 for anxiety and panic attacks, there is insufficient reliable information about the clinical effects of vitamin B12 for these uses.
• Asthma. Although there is interest in using oral vitamin B12 for asthma, there is insufficient reliable information about the clinical effects of vitamin B12 for this condition.
• Atherosclerosis. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical study in patients with intermediate risk for coronary heart disease shows that taking vitamin B12 100 mcg, aged garlic extract 250 mg, folic acid 300 mcg, vitamin B6 12.5 mg, and L-arginine 100 mg daily for 12 months reduces coronary artery calcium progression when compared with placebo (88385). It is unclear if this effect is due to vitamin B12, other ingredients, or the combination.
• Atopic dermatitis (eczema). It is unclear if topical vitamin B12 reduces the severity of eczema. Details: Preliminary clinical research shows that applying a specific topical vitamin B12 0.07% cream (Regividerm) twice daily reduces the extent and severity of atopic dermatitis when compared with placebo (15765).
• Attention. Although there is interest in using oral vitamin B12 for improving attention and focus, there is insufficient reliable information about the clinical effects of vitamin B12 for this use.
• Cancer. It is unclear if oral vitamin B12 reduces overall cancer risk when used in combination with other B vitamins. Details: An ancillary clinical study in middle-aged and elderly adults with cardiovascular disease shows that taking a combination of vitamin B12 (cyanocobalamin) 0.02 mg, folic acid 0.56 mg, and vitamin B6 3 mg, with or without eicosapentaenoic acid (EPA) 400 mg plus docosahexaenoic acid (DHA) 200 mg, for a median of 4.7 years does not reduce the risk of cancer when compared with placebo (90666). An additional secondary analysis of clinical research in patients recovering from stroke or transient ischemic attack shows that taking vitamin B12 500 mcg, folic acid 2 mg, and vitamin B6 25 mg daily for around 3.4 years does not reduce the risk of cancer when compared with placebo (90378). The validity of these findings is limited because the studies were not designed nor adequately powered to test for cancer risk.
• Cardiovascular disease (CVD). Oral vitamin B12, taken along with other B vitamins, does not seem to improve secondary prevention of death or myocardial infarction in patients with CVD. However, it might slightly reduce the risk of stroke. Details: Overall evidence from clinical research and meta-analyses shows that taking vitamin B12 in combination with folic acid and/or vitamin B6 does not seem to reduce the risk for secondary death or myocardial infarction in patients with or at risk for CVD (11387,13482,34540,50423,83050,90379,97619). In fact, some research suggests that long-term supplementation with vitamin B6, folic acid, and vitamin B12 for secondary prevention increases the risk of CVD by 20% despite lowering homocysteine levels by 30% (13482). However, other research shows that taking vitamin B12 in combination with other B vitamins modestly reduces the risk of stroke, although results are conflicting (11387,13482,50423,83050,96150,96165,97619,107136). It is unclear which specific combination of B vitamins, if any, might be optimal for reducing stroke risk and which patients are most likely to benefit. In 2001, prior to the publication of the highest quality research on this topic, the US Food and Drug Administration (FDA) approved a qualified health claim stating that, as part of a well-balanced diet that is low in saturated fat and cholesterol, folic acid, vitamin B6, and vitamin B12 may reduce the risk of vascular disease (102368).
• Cervical cancer. It is unclear if oral vitamin B12 reduces cervical cancer risk. Details: Some epidemiological evidence has found that increasing vitamin B12 intake from dietary and supplement sources, along with folic acid, thiamine, and riboflavin, might decrease the risk of precancerous cervical lesions (11074). Also, an analysis of two case control studies has found that increased intake of vitamin B12 is associated with a 75% reduced odds of cervical cancer (34609).
• Chemotherapy-induced peripheral neuropathy. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients receiving chemotherapy shows that a combination of B vitamins that includes vitamin B12 (cyanocobalamin) 1000 mcg, taken daily starting one week prior to treatment and finishing 12 weeks after treatment is completed, does not prevent peripheral neuropathy when compared with placebo (96173).
• Child development. It is unclear if oral vitamin B12 is beneficial for child development. Details: Population research has found that daily dietary intake of less than 2.26 mcg vitamin B12 in the third trimester of pregnancy is associated with an increased risk of poorer outcomes in the offspring for some measures of speech and mathematics ability, including vocabulary at 24 months, combining words at 38 months, speech intelligibility at 6 years, and math comprehension between ages 8-11 years, when compared with dietary intakes of at least 2.26 mcg daily. There was no association between prenatal vitamin B12 intake and reading or spelling abilities, vocabulary at other ages, or full-scale Intelligence Quotient (IQ) at ages 8 or 15 (107143).
• Chronic obstructive pulmonary disease (COPD). It is unclear if oral vitamin B12 reduces the risk of COPD. Details: Clinical research in patients with COPD shows that taking vitamin B12 500 mg daily for 8 weeks modestly improves endurance on the cycle ergometer, but does not improve oxygen consumption, when compared with placebo (96172).
• Cognitive function. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized clinical study in healthy, middle-aged adults shows that taking a combination product containing vitamin B12, other B vitamins, bacopa, and gingko biloba twice daily for 12 weeks does not improve measures of memory, attention, cognition, mood, or stress reactivity when compared with placebo (111554).
• Colorectal cancer. It is unclear if oral vitamin B12 reduces colorectal cancer risk. Details: Some epidemiological evidence has found that increased dietary intake of vitamin B12 is associated with a reduced risk of developing colorectal cancer (90383). However, preliminary clinical research shows that taking vitamin B12 1 mg, folic acid 2.5 mg, and vitamin B6 50 mg daily for up to 7.3 years does not reduce the risk of colorectal adenoma in females at high risk for cardiovascular disease (90389). Furthermore, a secondary analysis of clinical research in elderly patients suggests that taking vitamin B12 500 mcg and folic acid 400 mcg daily for 2 years might increase the risk of colorectal cancer when compared with placebo (90393).
• Coronavirus disease 2019 (COVID-19). It is unclear if oral vitamin B12 is beneficial for patients with COVID-19. Details: A small observational study in hospitalized patients with COVID-19 pneumonia has found that higher plasma vitamin B12 levels may be associated with an increased risk of transfer to intensive care or death than lower plasma levels. However, when multivariate regression was conducted, only patient age was associated with worsened outcomes. Additionally, the total study population was small, with only nine of 49 patients experiencing the worsened outcomes (107138).
• Dementia. It is unclear if oral vitamin B12 reduces the risk of developing dementia. Details: A large cohort of Danish adults has found that vitamin B12 levels or intake does not seem to impact the risk of developing Alzheimer disease or other dementias (104922). However, vitamin B12 might be beneficial in specific patient populations. A small observational study in patients with Parkinson disease has found that higher vitamin B12 levels (648.5 ng/L) are associated with a lower risk of developing dementia when compared with lower vitamin B12 levels (452 ng/L) (103975). It is not yet known if supplementation with vitamin B12 reduces the risk for dementia in these patients.
• Depression. It is unclear if oral vitamin B12 is beneficial for reducing depression risk. Details: A meta-analysis of epidemiological research has found that the highest dietary intake of vitamin B12 is associated with a 14% reduced risk of depression. However, in a sub-analysis, this association was not significant in males (107133). In contrast, one epidemiological study in older males included in the analysis has found that daily dietary intake of at least 4.79 mcg vitamin B12 is linked with a 58% lower risk of depression when compared with daily intake of less than 3.16 mcg. In this study, this inverse association was not observed in females (96168). Other observational research has found that low-normal serum vitamin B12 levels are associated with a 3.8 times increased risk for depression during pregnancy when compared with normal vitamin B12 levels (102384). It is unclear if increased intake of vitamin B12 through the diet or supplements reduces the risk for depression or is beneficial for treating symptoms of depression in any population. However, a meta-analysis of clinical research in elderly populations shows that supplementation with vitamin B12 100-1000 mcg daily, usually in combination with folic acid 400-2000 mcg daily, does not reduce symptoms of depression. Most individuals in these studies were not specifically diagnosed with depression (107140).
• Diabetes. It is unclear if oral vitamin B12 improves glycemic indices or prevents loss of skeletal muscle in patients with diabetes. Details: A small clinical study in patients with diabetes in India who are stabilized on metformin and/or a sulfonylurea shows that taking vitamin B12 (methylcobalamin) 500 mcg with or without folic acid 5 mg daily for 8 weeks seems to reduce glycated hemoglobin (HbA1C) by 1.3% to 1.5%, compared with a 0.3% increase with placebo (104917). This study is limited due its small sample size and lack of blinding. In elderly adults with type 2 diabetes, population research has found a lower dietary intake of vitamin B12 (average of 11.2 mcg daily) in individuals with a loss of skeletal muscle mass of at least 1.2%, compared with an average intake of 13.4 mcg daily in those with a skeletal muscle mass loss of less than 1.2%. However, further analysis determined that any relationship between vitamin B12 intake and loss of skeletal muscle mass was only significant in individuals with insufficient energy intake overall (107151).
• Diabetic neuropathy. Small clinical studies suggest that oral vitamin B12 may modestly improve pain in patients with diabetic neuropathy. Details: Two small clinical studies in patients with diabetic peripheral neuropathy show that taking vitamin B12 (methylcobalamin) 1-1.5 mg for 4-12 months modestly improves pain when compared with baseline or placebo (82841,104923). Some research also shows that vitamin B12 may be beneficial in combination with other ingredients. Studies have evaluated products containing vitamin B12 (methylcobalamin or cyanocobalamin), benfotiamine, and vitamin B6 daily for 9-12 weeks (82931,82939); and vitamin B12 (methylcobalamin) 2 mg, folic acid (L-methylfolate) 3 mg, and vitamin B6 (pyridoxal-5'-phosphate) 35 mg (Metanx; Pamlab) daily for 24 weeks (90375).
• Diarrhea. It is unclear if oral vitamin B12 is beneficial for reducing diarrhea in children. Details: Preliminary clinical research in children aged 6-30 months from low- and middle-income countries shows that taking vitamin B12 at twice the recommended dietary allowance, with or without folic acid, does not reduce the risk for diarrhea when compared with placebo (90391).
• Fatigue. It is unclear if intramuscular vitamin B12 is beneficial for improving well-being in those with fatigue or tiredness. Details: A small crossover trial in patients complaining of tiredness or fatigue shows that receiving intramuscular injections of vitamin B12 (hydroxocobalamin) 5 mg twice weekly for 2 weeks seems to improve general well-being and happiness, and has a trend toward improving fatigue, when compared with placebo (10127). The validity of this study is limited by a large drop-out rate and unstandardized outcome measures.
• Hearing loss. Oral vitamin B12 has only been evaluated in combination with adenosine triphosphate; its effect when used alone is unclear. Details: A small observational study in adults with idiopathic sudden sensorineural hearing loss has found that taking vitamin B12 1.5 mg with adenosine triphosphate 300 mg daily for 8-16 weeks is associated with modestly reduced hearing loss at 4-6 months after starting treatment when compared with taking the combination for less than 8 weeks (104924). This finding is limited due to its observational nature and lack of a control group.
• Hepatitis C. It is unclear if intramuscular vitamin B12 is beneficial for sustaining viral response in patients with chronic hepatitis C infection. Details: A small clinical study in patients with chronic hepatitis C infection shows that intramuscular vitamin B12 (cyanocobalamin) 5000 mcg every 4 weeks along with standard care improves sustained viral response when compared with standard of care alone (90386).
• Hypertriglyceridemia. It is unclear if oral vitamin B12 is beneficial for reducing triglyceride levels. Details: Some evidence shows that taking vitamin B12 7.5 mcg with fish oil 5 grams might be superior to fish oil alone when used daily to reduce total serum cholesterol and triglycerides. This suggests vitamin B12 might have an independent effect in lowering serum cholesterol and triglycerides, but further investigation is needed to confirm this effect (8694).
• Infant development. It is unclear if taking oral vitamin B12 during pregnancy is beneficial for improving infant development. Giving oral vitamin B12 to infants does not seem to be beneficial. Details: Clinical research shows that supplementation with vitamin B12 50 mcg daily from less than 14 weeks gestation until 6 weeks postpartum does not improve cognitive development in infants by 9 months of age when compared with placebo (96174). When these children were evaluated at 30 months of age, a very small benefit of vitamin B12 on expressive language was identified; however, there was no effect on cognition, receptive language, fine motor skills, or gross motor skills (100169). It is unknown whether a longer duration of postpartum supplementation or supplementation in specific populations might be beneficial. Vitamin B12 supplementation in infants has also been evaluated. A large clinical trial in marginally stunted Nepalese infants aged 6-11 months shows that giving vitamin B12 (cyanocobalamin) 2 mcg daily for 12 months reduces homocysteine levels, but does not improve motor or cognitive development, when compared with placebo (104926).
• Inflammatory bowel disease (IBD). Although there is interest in using oral vitamin B12 for IBD, there is insufficient reliable information about the clinical effects of vitamin B12 for this condition.
• Lung cancer. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: The association between vitamin B12 and lung cancer is unclear. Some population research found no relationship between blood levels of vitamin B12 and lung cancer (9454). However, other observational research involving over 5,000 case-control pairs found that higher vitamin B12 levels are linked with an increased risk for lung cancer (102383). It is unclear if increased intake of vitamin B12, either through the diet or supplementation, directly affects the risk of lung cancer.
• Male infertility. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A retrospective study in adult males with idiopathic and varicocele-related infertility suggests that taking a combination product containing vitamin B12 1.5 mcg, L-carnitine, acetyl L-carnitine, citric acid, selenium, coenzyme Q10, vitamin C, zinc, and folic acid (Proxeed Plus) twice daily for 6 months is associated with improvements in ejaculate volume, sperm count, sperm concentration, total motility, and progressive motility in patients with idiopathic infertility when compared to baseline. However, improvement in sperm morphology was lacking. Furthermore, patients with more severe varicocele seem to benefit most, especially with regard to progressive motility (111296). The validity of these findings is limited by a lack of comparator group. Further, it is unclear if these effects are due to vitamin B12, other ingredients, or the combination.
• Multiple sclerosis (MS). Although there is interest in using oral vitamin B12 for MS, there is insufficient reliable information about the clinical effects of vitamin B12 for this condition.
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral vitamin B12 is beneficial for NAFLD. Details: A small clinical study in adults with NAFLD shows that taking vitamin B12 1000 mcg daily for 12 weeks reduces serum levels of homocysteine but has no effect on serum aminotransferases, measures of steatosis, fibrosis scores, fasting blood glucose, serum insulin, measures of insulin resistance, triglycerides, low-density lipoprotein (LDL) cholesterol, or high-density lipoprotein (HDL) cholesterol when compared with placebo (111555).
• Pancreatic cancer. It is unclear if oral vitamin B12 is beneficial for reducing the risk of pancreatic cancer. Details: Most population research has found that increased intake of vitamin B12, as a supplement or in the diet, is not associated with a reduced risk of pancreatic cancer (9327,104927). However, a small, retrospective population study in which smoking and non-smoking adults recalled past eating habits found that increased dietary intake of vitamin B12 is associated with a 33% reduction in pancreatic cancer risk (97976). These conflicting findings may be related to study methodology, as well as the age, gender, or smoking status of the included patients.
• Periodontitis. Although there is interest in using oral vitamin B12 for periodontitis, there is insufficient reliable information about the clinical effects of vitamin B12 for this condition.
• Peripheral neuropathy. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a specific product containing vitamin B12 3 mcg, folic acid 400 mcg, and uridine monophosphate 50 mg (Keltican) daily for 60 days reduces pain by 44% and decreases analgesic use by over 75% when compared to baseline in patients with peripheral neuropathy, including those with lumbar/lumbosacral radiculopathy, sciatic pain, and cervical radiculopathy (90384). The validity of this finding is limited by the lack of a control group. Furthermore, it is unclear if the benefits are due to vitamin B12, other ingredients, or the combination.
• Psoriasis. Topical vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that a specific cream containing vitamin B12 and avocado oil (Regividerm, Regeneratio Pharma AG) reduces symptoms of psoriasis as effectively as calcipotriol ointment (Psorcutan) after 12 weeks of therapy. The vitamin B12 combination cream also causes less irritation than calcipotriol (14909). It is unclear if the benefits are due to vitamin B12, other ingredients, or the combination.
• Respiratory tract infections. A small study suggests that oral vitamin B12 does not reduce the rate of respiratory tract infections in children. Details: Preliminary clinical research in children aged 6-30 months from low-and middle-income countries suggests that taking vitamin B12 at twice the recommended dietary allowance with or without folic acid does not reduce the risk for lower respiratory tract infections when compared with placebo (90391).
• Schizophrenia. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research shows that taking a combination of vitamin B12 400 mcg and folic acid 2 mg daily for 16 weeks improves negative symptoms when compared with placebo in patients with schizophrenia who have persistent symptoms and a specific genetic variant of the folate transporter gene FOLHI. This variant normally results in reduced folate absorption. However, in patients without this genetic variant, folate is not beneficial with respect to negative symptom improvement (90387).
• Sickle cell disease. Oral vitamin B12 has only been evaluated in combination with other B vitamins; its effect when used alone is unclear. Details: Preliminary clinical research in adults with sickle cell disease shows that taking vitamin B12 4.2-6 mcg, folic acid 700 mcg, and vitamin B6 4.2-6 mg daily might lower homocysteine levels. However, it is unknown if this will reduce the risk of endothelial damage in these patients (9324).
• Stroke. It is unclear if oral vitamin B12, either alone or with other B vitamins, is beneficial for stroke prevention. Details: Epidemiological research has found that people with a higher intake of vitamin B12 from dietary sources do not have a reduced risk of ischemic or hemorrhagic stroke (14316). A number of clinical studies and meta-analyses show that supplementation with folic acid, vitamin B6, and vitamin B12, alone or in combination, does not reduce the risk of stroke in patients with cardiovascular disease (CVD) or impaired kidney function (11387,13482,50420,50423,83050,90379,90380,96150). However, a more recent meta-analysis of 10 clinical trials including over 44,000 patients shows that B vitamin supplementation modestly reduces the relative risk of stroke by 10% when compared with placebo in patients at risk or with a history of CVD (97619). This meta-analysis differed from some of the earlier analyses due to the inclusion of several additional clinical trials. Also, a meta-analysis in adults with a history of stroke shows that B vitamin supplementation modestly reduces the relative risk of stroke recurrence by 13% and vascular death by 11% when compared with placebo (107136). In 2001, prior to the publication of the highest quality research on this topic, the US Food and Drug Administration (FDA) allowed a qualified health claim stating that, as part of a well-balanced diet that is low in saturated fat and cholesterol, folic acid, vitamin B6, and vitamin B12 may reduce the risk of vascular disease (102368). Unfortunately, even after the publication of higher quality research, it is still unclear which specific combination of B vitamins is optimal and which patients are most likely to benefit. One network meta-analysis suggests that a combination of folic acid and vitamin B6 lowers the risk of stroke more effectively than B vitamin mixtures that include vitamin B12 (96165). However, this analysis is limited because it didn't account for dosing. Another meta-analysis suggests that exposure to low, but not high, amounts of vitamin B12 (cyanocobalamin) seems to reduce stroke risk (96150).
• Tinnitus. It is unclear if intramuscular vitamin B12 is beneficial in patients with tinnitus. Details: A small clinical study shows that intramuscular vitamin B12 2500 mcg weekly for 6 weeks reduces tinnitus severity by 22% when compared to baseline in patients with chronic tinnitus and vitamin B12 deficiency, but not in patients with normal levels of vitamin B12. Vitamin B12 does not improve pitch or volume in either group of patients (96170). The validity of this finding is limited by the lack of a control group.
• Venous thromboembolism (VTE). It is unclear if oral vitamin B12 is beneficial for preventing VTE. Details: Epidemiological research has found that low levels of vitamin B12 are associated with an increased risk for VTE. However, clinical trials evaluating the use of B vitamins for prevention of VTE have shown conflicting results (90398). More evidence is needed to rate vitamin B12 for these uses.

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LIKELY SAFE ...when used orally and appropriately. Biotin has been safely used in doses up to 300 mg daily for up to 6 months. A tolerable upper intake level (UL) has not been established (1900,6243,95662,102965). ...when applied topically as cosmetic products at concentrations of 0.0001% to 0.6% biotin (19344).

POSSIBLY SAFE ...when used intramuscularly and appropriately (8468,111366).

CHILDREN: LIKELY SAFE
when used orally and appropriately. Biotin has been safely used at adequate intake doses of 5-25 mcg daily for up to 6 months (173,6243,19347,19348,111365). A tolerable upper intake level (UL) has not been established.

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately. Biotin has been safely used at the adequate intake (AI) dose of 30 mcg daily during pregnancy and 35 mcg daily during lactation. It has also been used in supplemental doses of up to 300 mcg daily (6243,7878). A tolerable upper intake level (UL) has not been established.

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POSSIBLY SAFE ...when used orally and appropriately, short-term. Collagen peptides have been used with apparent safety at doses up to 10 grams daily for up to 6 months and in doses up to 40 grams daily for up to 4 weeks (97632,97635,101615,101621,104638,104643,104644,104647,101622,110667). PREGNANCY &

LACTATION:
Insufficient reliable information available; avoid using.

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LIKELY SAFE ...when used orally and appropriately. Supplements standardized to contain hyaluronic acid 70%, in an 80 mg daily dose, have been used daily for up to 3 months with no reports of adverse effects (55742,91779). ...when used topically and appropriately. Hyaluronic acid, in a gel or impregnated gauze, has been safely applied to the skin in clinical trials (7889,7892,104389,108627,108640). ...when eye drop preparations containing up to 0.3% hyaluronic acid are used multiple times per day for up to 3 months (97885,97894,97895,110555).

PREGNANCY:
There is insufficient reliable information available about the safety of hyaluronic acid; avoid using.

LACTATION:
There is insufficient reliable information available about the safety of hyaluronic acid. It is not known if hyaluronic acid is excreted in breast milk (7890); avoid using.

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POSSIBLY SAFE ...when used orally and appropriately, short-term. Shark cartilage has been used with apparent safety in clinical trials lasting up to 24 weeks (2015,4893,4938,6709,6716,6717,13086,74741) and for up to 40 months in patients with advanced cancer (10900,17102). ...when used topically and appropriately, short-term. Shark cartilage appears to be safe when applied topically for up to 8 weeks (74729).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

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LIKELY SAFE ...when used orally and appropriately. Sodium is safe in amounts that do not exceed the Chronic Disease Risk Reduction (CDRR) intake level of 2.3 grams daily (100310). Higher doses can be safely used therapeutically with appropriate medical monitoring (26226,26227).

POSSIBLY UNSAFE ...when used orally in high doses. Tell patients to avoid exceeding the CDRR intake level of 2.3 grams daily (100310). Higher intake can cause hypertension and increase the risk of cardiovascular disease (26229,98176,98177,98178,98181,98183,98184,100310,109395,109396,109398,109399). There is insufficient reliable information available about the safety of sodium when used topically.

CHILDREN: LIKELY SAFE
when used orally and appropriately (26229,100310). Sodium is safe in amounts that do not exceed the CDRR intake level of 1.2 grams daily for children 1 to 3 years, 1.5 grams daily for children 4 to 8 years, 1.8 grams daily for children 9 to 13 years, and 2.3 grams daily for adolescents (100310).

CHILDREN: POSSIBLY UNSAFE
when used orally in high doses. Tell patients to avoid prolonged use of doses exceeding the CDRR intake level of 1.2 grams daily for children 1 to 3 years, 1.5 grams daily for children 4 to 8 years, 1.8 grams daily for children 9 to 13 years, and 2.3 grams daily for adolescents (100310). Higher intake can cause hypertension (26229).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately. Sodium is safe in amounts that do not exceed the CDRR intake level of 2.3 grams daily (100310).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in higher doses. Higher intake can cause hypertension (100310). Also, both the highest and the lowest pre-pregnancy sodium quintile intakes are associated with an increased risk of hypertensive disorders of pregnancy, including gestational hypertension and pre-eclampsia, and the delivery of small for gestational age (SGA) infants when compared to the middle intake quintile (106264).

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LIKELY SAFE ...when used orally, topically, intravenously, intramuscularly, or intranasally and appropriately. Vitamin B12 is generally considered safe, even in large doses (15,1344,1345,1346,1347,1348,2909,6243,7289,7881)(9414,9416,10126,14392,15765,82832,82949,82860,82864,90386)(111551,111554).

PREGNANCY: LIKELY SAFE
when used orally in amounts that do not exceed the recommended dietary allowance (RDA). The RDA for vitamin B12 during pregnancy is 2.6 mcg daily (6243). There is insufficient reliable information available about the safety of larger amounts of vitamin B12 during pregnancy.

LACTATION: LIKELY SAFE
when used orally in amounts that do not exceed the recommended dietary allowance (RDA). The RDA of vitamin B12 during lactation is 2.8 mcg daily (6243). There is insufficient reliable information available about the safety of larger amounts of vitamin B12 while breastfeeding.

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IMMUNOSUPPRESSANTS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, shark cartilage might interfere with immunosuppressive therapy.  Details In vitro evidence suggests that shark cartilage might stimulate immune responses (74692,74700,93050). This effect has not been reported in humans.

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ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = A Theoretically, a high intake of dietary sodium might reduce the effectiveness of antihypertensive drugs.  Details High intake of dietary sodium can increase systolic and diastolic blood pressure (26222). Also, high intake of sodium may necessitate increased use of antihypertensive medications to achieve blood pressure control in some patients, such as those with chronic kidney disease (26223).

CORTICOSTEROIDS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Concomitant use of mineralocorticoids and some glucocorticoids with sodium supplements might increase the risk of hypernatremia.  Details Mineralocorticoids and some glucocorticoids (corticosteroids) cause sodium retention. This effect is dose-related and depends on mineralocorticoid potency. It is most common with hydrocortisone, cortisone, and fludrocortisone, followed by prednisone and prednisolone (4425).

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Altering dietary intake of sodium might alter the levels and clinical effects of lithium.  Details High sodium intake can reduce plasma concentrations of lithium by increasing lithium excretion (26225). Reducing sodium intake can significantly increase plasma concentrations of lithium and cause lithium toxicity in patients being treated with lithium carbonate (26224,26225). Stabilizing sodium intake is shown to reduce the percentage of patients with lithium level fluctuations above 0.8 mEq/L (112909). Patients taking lithium should avoid significant alterations in their dietary intake of sodium.

SODIUM-CONTAINING DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Concomitant use of sodium-containing drugs with additional sodium from dietary or supplemental sources may increase the risk of hypernatremia and long-term sodium-related complications.  Details The Chronic Disease Risk Reduction (CDRR) intake level of 2.3 grams of sodium daily indicates the intake at which it is believed that chronic disease risk increases for the apparently healthy population (100310). Some medications contain high quantities of sodium. When used in conjunction with sodium supplements or high-sodium diets, the CDRR may be exceeded. Additionally, concomitant use may increase the risk for hypernatremia; this risk is highest in the elderly and people with other risk factors for electrolyte disturbances.

TOLVAPTAN (Samsca) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Theoretically, concomitant use of tolvaptan with sodium might increase the risk of hypernatremia.  Details Tolvaptan is a vasopressin receptor 2 antagonist that is used to increase sodium levels in patients with hyponatremia (29406). Patients taking tolvaptan should use caution with the use of sodium salts such as sodium chloride.

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General ...Orally and topically, biotin is generally well tolerated.
Most Common Adverse Effects: None.

Gastrointestinal ...Orally, high-dose biotin has been rarely associated with mild diarrhea. Transient mild diarrhea was reported by 2 patients taking biotin 300 mg daily (95662).

Pulmonary/Respiratory ...In one case report in France, a 76-year-old female frequent traveler developed eosinophilic pleuropericarditis after taking biotin 10 mg and pantothenic acid 300 mg daily for 2 months. She had also been taking trimetazidine for 6 years (3914). Whether eosinophilia in this case was related to biotin, pantothenic acid, other substances, or patient-specific conditions is unknown. There have been no other similar reports.

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General ...Orally, collagen peptides seem to be well tolerated.

Dermatologic ...Orally, a case of a mild skin rash has been reported for a patient who used a specific collagen peptide-containing product (BioCell Collagen) (28680).

Gastrointestinal ...Orally, collagen peptides may cause nausea, dyspepsia, diarrhea, and flatulence, but these adverse effects are rare (101622,104639).

(Read more about COLLAGEN PEPTIDES)

General ...Orally and topically, hyaluronic acid appears to be well tolerated.
Most Common Adverse Effects:
Topically: Eczema, erythema, itching, wound hemorrhage, wound infection (e.g., erysipelas).

Dermatologic ...The use of needle-free devices to inject hyaluronic acid for cosmetic purposes has been reported to cause serious injury, and in some cases permanent harm, to the skin, lips, and eyes (108613).
Topically, hyaluronic acid application has been reported to cause eczema, erythema, itching, wound hemorrhage, and wound infection (e.g., erysipelas) (108628,108640).

Ocular/Otic ...Ocular pain has been reported rarely in patients using eye drops containing up to 0. 3% hyaluronic acid (97885).

(Read more about HYALURONIC ACID)

General ...Orally, shark cartilage is generally well tolerated.
Most Common Adverse Effects:
Orally: Constipation, dizziness, dyspepsia, erythema, fatigue, hypotension, nausea, taste disturbance, and vomiting.
Serious Adverse Effects (Rare):
Orally: Altered consciousness, decreased motor strength, decreased sensation, generalized weakness, hepatitis, hyperglycemia, hypoglycemia, and peripheral edema.

Cardiovascular ...Orally, shark cartilage can cause hypotension and peripheral edema (2014,2015,6716,10900).

Endocrine ...Orally, shark cartilage can cause hyperglycemia, hypoglycemia, and hypercalcemia (2014,2015,6716,10900,74724).

Gastrointestinal ...Orally, shark cartilage can cause taste disturbances, nausea, vomiting, dyspepsia, constipation, cramping, and bloating (2014,2015,6716,10900,74724,74730,74731).

Hepatic ...Orally, shark cartilage can cause acute hepatitis, with symptoms including low-grade fever, jaundice, yellowing of the eyes, right upper quadrant tenderness, and elevated liver enzymes (2012).

Musculoskeletal ...Orally, shark cartilage can cause decreased motor strength, generalized weakness, and decreased performance (2014,2015,6716,10900).

Neurologic/CNS ...Orally, shark cartilage can cause dizziness, altered consciousness, decreased sensation, and fatigue (2014,2015,6716,10900,74725).

(Read more about SHARK CARTILAGE)

General ...Orally, sodium is well tolerated when used in moderation at intakes up to the Chronic Disease Risk Reduction (CDRR) intake level. Topically, a thorough evaluation of safety outcomes has not been conducted.
Serious Adverse Effects (Rare):
Orally: Worsened cardiovascular disease, hypertension, kidney disease.

Cardiovascular ...Orally, intake of sodium above the CDRR intake level can exacerbate hypertension and hypertension-related cardiovascular disease (CVD) (26229,98176,100310,106263). A meta-analysis of observational research has found a linear association between increased sodium intake and increased hypertension risk (109398). Observational research has also found an association between increased sodium salt intake and increased risk of CVD, mortality, and cardiovascular mortality (98177,98178,98181,98183,98184,109395,109396,109399). However, the existing research is unable to confirm a causal relationship between sodium intake and increased cardiovascular morbidity and mortality; high-quality, prospective research is needed to clarify this relationship (100312). As there is no known benefit with increased salt intake that would outweigh the potential increased risk of CVD, advise patients to limit salt intake to no more than the CDRR intake level (100310).
A reduction in sodium intake can lower systolic blood pressure by a small amount in most individuals, and diastolic blood pressure in patients with hypertension (100310,100311,106261). However, post hoc analysis of a small crossover clinical study in White patients suggests that 24-hour blood pressure variability is not affected by high-salt intake compared with low-salt intake (112910). Additionally, the available research is insufficient to confirm that a further reduction in sodium intake below the CDRR intake level will lower the risk for chronic disease (100310,100311). A meta-analysis of clinical research shows that reducing sodium intake increases levels of total cholesterol and triglycerides, but not low-density lipoprotein (LDL) cholesterol, by a small amount (106261).
It is unclear whether there are safety concerns when sodium is consumed in amounts lower than the adequate intake (AI) levels. Some observational research has found that the lowest levels of sodium intake might be associated with increased risk of death and cardiovascular events (98181,98183). However, this finding has been criticized because some of the studies used inaccurate measures of sodium intake, such as the Kawasaki formula (98177,98178,101259). Some observational research has found that sodium intake based on a single 24-hour urinary measurement is inversely correlated with all-cause mortality (106260). The National Academies Consensus Study Report states that there is insufficient evidence from observational studies to conclude that there are harmful effects from low sodium intake (100310).

Endocrine ...Orally, a meta-analysis of observational research has found that higher sodium intake is associated with an average increase in body mass index (BMI) of 1. 24 kg/m2 and an approximate 5 cm increase in waist circumference (98182). It has been hypothesized that the increase in BMI is related to an increased thirst, resulting in an increased intake of sugary beverages and/or consumption of foods that are high in salt and also high in fat and energy (98182). One large observational study has found that the highest sodium intake is not associated with overweight or obesity when compared to the lowest intake in adolescents aged 12-19 years when intake of energy and sugar-sweetened beverages are considered (106265). However, in children aged 6-11 years, usual sodium intake is positively associated with increased weight and central obesity independently of the intake of energy and/or sugar-sweetened beverages (106265).

Gastrointestinal ...In one case report, severe gastritis and a deep antral ulcer occurred in a patient who consumed 16 grams of sodium chloride in one sitting (25759). Chronic use of high to moderately high amounts of sodium chloride has been associated with an increased risk of gastric cancer (29405).

Musculoskeletal ...Observational research has found that low sodium levels can increase the risk for osteoporosis. One study has found that low plasma sodium levels are associated with an increased risk for osteoporosis. Low levels, which are typically caused by certain disease states or chronic medications, are associated with a more than 2-fold increased odds for osteoporosis and bone fractures (101260).
Conversely, in healthy males on forced bed rest, a high intake of sodium chloride (7.7 mEq/kg daily) seems to exacerbate disuse-induced bone and muscle loss (25760,25761).

Oncologic ...Population research has found that high or moderately high intake of sodium chloride is associated with an increased risk of gastric cancer when compared with low sodium chloride intake (29405). Other population research in patients with gastric cancer has found that a high intake of sodium is associated with an approximate 65% increased risk of gastric cancer mortality when compared with a low intake. When zinc intake is taken into consideration, the increased risk of mortality only occurred in those with low zinc intake, but the risk was increased to approximately 2-fold in this sub-population (109400).

Pulmonary/Respiratory ...In patients with hypertension, population research has found that sodium excretion is modestly and positively associated with having moderate or severe obstructive sleep apnea. This association was not found in normotensive patients (106262).

Renal ...Increased sodium intake has been associated with impaired kidney function in healthy adults. This effect seems to be independent of blood pressure. Observational research has found that a high salt intake over approximately 5 years is associated with a 29% increased risk of developing impaired kidney function when compared with a lower salt intake. In this study, high salt intake was about 2-fold higher than low salt intake (101261).

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General ...Orally, intramuscularly, and topically, vitamin B12 is generally well-tolerated.
Most Common Adverse Effects:
Intramuscular: Injection site reactions.
Serious Adverse Effects (Rare):
Intramuscularly: Severe hypokalemia has been rarely linked with correction of megaloblastic anemia with vitamin B12.

Cardiovascular ...In human clinical research, an intravenous loading dose of folic acid, vitamin B6, and vitamin B12, followed by daily oral administration after coronary stenting, increased restenosis rates (12150). Hypertension following intravenous administration of hydroxocobalamin has been reported in human research (82870,82864).

Dermatologic ...Orally or intramuscularly, vitamin B12 can cause allergic reaction such as rash, pruritus, erythema, and urticaria. Theoretically, allergic reactions might be caused by the cobalt within the vitamin B12 molecule (82864,90373,90381,103974). In one case report, oral methylcobalamin resulted in contact dermatitis in a 59-year-old Japanese woman with a cobalt allergy (103974). Vitamin B12 (intramuscular or oral) has also been associated with at least 19 cases of acneiform eruptions which resolved upon discontinuation of vitamin B12 (90365,90369,90388). High-dose vitamin B12 (20 mcg daily) and vitamin B6 (80 mg daily) have been associated with cases of rosacea fulminans characterized by intense erythema with nodules, papules, and pustules. Symptoms may last up to four months after the supplement is stopped and can be treated with systemic corticosteroids and topical therapy (10998,82870,82871).

Gastrointestinal ...Intravenously, vitamin B12 (hydroxocobalamin) 2. 5-10 grams can cause nausea and dysphagia (82864).

Genitourinary ...Intravenously, vitamin B12 (hydroxocobalamin) 5-15 grams has been associated with chromaturia in clinical research (82870,82871).

Hematologic ...According to case report data, the correction of megaloblastic anemia with vitamin B12 may result in fatal hypokalemia (82914).

Musculoskeletal ...According to case report data, correction of megaloblastic anemia with vitamin B12 has precipitated gout in susceptible individuals (82879).

Neurologic/CNS ...Treatment with vitamin B12 has been rarely associated with involuntary movements in infants with vitamin B12 deficiency (90370,90385,90397). In some cases these adverse reactions were misdiagnosed as seizures or infantile tremor syndrome (90370,90385). These adverse reactions presented 2-5 days after treatment with vitamin B12 and resolved once vitamin B12 was discontinued (90370,90385,90397).

Oncologic ...Although some epidemiological research disagrees (9454), most research has found that elevated plasma levels of vitamin B12 are associated with an increased risk of various types of cancer, including lung and prostate cancers and solid tumors (50411,102383,107743). One study found, when compared with blood levels of vitamin B12 less than 1000 ng/mL, plasma vitamin B12 levels of at least 1000 ng/mL was strongly associated with the occurrence of solid cancer (107743). It is unclear if increased intake of vitamin B12, either through the diet or supplementation, directly affects the risk of cancer. It is possible that having cancer increases the risk of vitamin B12 elevation. However, one observational study has found that the highest quintile of dietary intake of vitamin B12 is associated with a 75% increased incidence of developing esophageal cancer when compared with the lowest quintile in never drinkers, but not drinkers (107147).

Renal ...There is a case report of oxalate nephropathy in a 54-year-old male which was determined to be related to the use of intravenous hydroxocobalamin as treatment for cyanide poisoning. Intermittent hemodialysis was started 5 days after admission, along with a low-oxalate diet, oral calcium acetate, and pyridoxine 5 mg/kg daily (107148). A review of the use of intravenous hydroxocobalamin for suspected cyanide poisoning in 21 intensive care units in France between 2011 and 2017 resulted in a 60% increased odds of acute kidney injury and a 77% increased odds of severe acute kidney injury in the first week. However, biopsies were not conducted and a direct link with use of hydroxocobalamin could not be made (107139).

Other ...Several studies have found that higher vitamin B12 levels may be associated with increased mortality or decreased survival rates in hospitalized elderly patients (82889,82812,82857,82895). Human research has also found a positive correlation between vitamin B12 status and all-cause mortality in Pima Indians with diabetes (82863).

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