Derma Beauty HA Skin Rejuvenating Serum by Health Logics Laboratories, Inc.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Depression. Although there has been interest in using oral 1,4-butanediol for depression, there is insufficient reliable information about the clinical effects of 1,4-butanediol for this purpose.
• Insomnia. Although there has been interest in using oral 1,4-butanediol for insomnia, there is insufficient reliable information about the clinical effects of 1,4-butanediol for this purpose.
• Muscle strength. Although there has been interest in using oral 1,4-butanediol to increase muscle strength, there is insufficient reliable information about the clinical effects of 1,4-butanediol for this purpose.
• Obesity. Although there has been interest in using oral 1,4-butanediol for weight loss, there is insufficient reliable information about the clinical effects of 1,4-butanediol for this purpose. More evidence is needed to rate 1,4-butanediol for these uses.

(Read more about 1,4-BUTANEDIOL)

POSSIBLY EFFECTIVE

• Cataracts. Chondroitin sulfate in combination with sodium hyaluronate is approved as a medical device to be ophthalmically injected during cataract surgery. It is unknown if other routes of administration are beneficial. Details: Injecting ophthalmic viscosurgical devices (OVDs) containing a combination of chondroitin sulfate and sodium hyaluronate into the eye protects the corneal endothelium during small-incision cataract surgery. Various medical devices containing chondroitin sulfate and sodium hyaluronate (Viscoat, Alcon Laboratories) have been granted approval by US Food and Drug Administration (FDA) for use as an adjunct to cataract surgery (89436,89437). However, OVDs that cannot be easily removed after surgery can cause intraocular pressure (IOP) spikes and reduced visual acuity. A meta-analysis of small clinical studies shows that using a specific chondroitin sulfate 4% and sodium hyaluronate 3% solution (Viscoat, Alcon Laboratories) after small-incision cataract surgery increases IOP at postoperative days 1 and 2, but not at any later postoperative days for up to 1 month (104452).
• Osteoarthritis. Chondroitin sulfate seems to modestly reduce osteoarthritis pain and improve function. Pharmaceutical-grade chondroitin sulfate products have shown the most benefit. Details: Meta-analyses of randomized controlled trials in patients with mostly knee osteoarthritis show that taking chondroitin sulfate 800-2000 mg in single or divided doses daily for at least 3 months modestly reduces pain and disability when compared with placebo. However, included studies were heterogeneous and most had high attrition bias. A sub-group analysis of high-quality studies shows that 16 patients need to take chondroitin sulfate for 6 months for one patient to experience at least a 20% reduction in pain (94381,95792,99685,104446). When compared with conventional treatments like diclofenac 50 mg three times daily, chondroitin sulfate improves symptoms more slowly; however, the improvement seems to persist for up to 3 months after treatment cessation (322). Chondroitin also seems to have disease-modifying benefits. Clinical research in patients with osteoarthritis of the knee or hip shows that taking chondroitin sulfate 800 mg daily or more for 2 years might modestly reduce joint degeneration and narrowing when compared with placebo or celecoxib (42348,42398,94381,95516). Overall, most of the positive research involved pharmaceutical-grade chondroitin sulfate products, which are available as prescription products in some countries, such as Chondrosulf (IBSA Institut Biochimique SA) (17732,42348,42398,42536,89596,94360,104446), Chondrosan (Bioibérica, S.A.) (42463,42513), and Structum (Laboratoires Pierre Fabre) (22212,42520,89593). One clinical study shows that taking a pharmaceutical-grade chondroitin product (Chondrosulf) 800 mg daily seems to be comparable to taking celecoxib 200 mg daily for reducing pain and improving knee function (94360). Pharmaceutical-grade chondroitin products might demonstrate greater benefit due to higher quality (94360,102116). It is also important to note that most clinical studies using pharmaceutical-grade products are manufacturer-funded (94381). Furthermore, they may not be readily available for purchase in the US. Experts have conflicting stances on the use of chondroitin for osteoarthritis. The American College of Rheumatology (ACR) strongly recommends against the use of chondroitin for any form of osteoarthritis (102114). Conversely, the European Society of Clinical and Economic Aspects of Osteoarthritis (ESCEO) strongly recommends for the use of pharmaceutical-grade chondroitin products. Additionally, the ESCEO provides a weak recommendation against the use of chondroitin in combination with glucosamine (102141). These differing recommendations seem to be related to interpretation of the evidence for pharmaceutical-grade products. The ACR has determined that the inconsistent evidence may indicate the presence of industry bias; the ESCEO has determined that the inconsistent evidence is due to inconsistent product quality. Chondroitin is often used in combination with glucosamine and/or other products. Long-term studies in patients with osteoarthritis show that taking non-branded chondroitin sulfate with glucosamine sulfate modestly reduces joint-space narrowing when compared with control (89558,94380,95792). However, meta-analyses and individual clinical studies assessing non-branded preparations of chondroitin sulfate with glucosamine hydrochloride or glucosamine sulfate do not show reduced pain in patients with knee osteoarthritis when compared with control (13579,89558,95788,99683,99685). In contrast, pain reduction was reported for branded formulations such as chondroitin sulfate with glucosamine hydrochloride and manganese ascorbate (Cosamin DS, Nutramax Laboratories) (4237,7169); chondroitin sulfate with glucosamine hydrochloride (Droglican, Bioiberica, S.A.) (89516); or chondroitin sulfate with collagen peptides and hyaluronic acid (BioCell Collagen, BioCell Technology, LLC) (28678,28680). A large, prospective observational study in adults with knee or hip osteoarthritis suggests that taking glucosamine hydrochloride 500 mg and chondroitin sulfate 400 mg (Theraflex, Bayer) three times daily for the first 3 weeks, then twice daily thereafter for up to 64 weeks, is associated with reductions in pain, stiffness, and the need for concomitant analgesic therapy, and improvements in daily function and knee- or hip-related quality of life, when compared to baseline. The most pronounced improvements are from 16-24 weeks (111647). It is unclear if the benefit seen with these specific products is due to bias introduced by industry funding or due to higher quality. Limited research has also evaluated INTRAMUSCULAR and TOPICAL chondroitin. Some clinical research shows that receiving daily intramuscular injections of chondroitin sulfate for 6 months improves pain and function in patients with osteoarthritis (42396,42397). A topical preparation of chondroitin sulfate in combination with glucosamine sulfate, shark cartilage, and camphor also seems to reduce arthritis symptoms. However, any symptom relief is most likely due to the counterirritant effect of camphor and not the other ingredients (10327). There is no research showing that chondroitin is absorbed topically.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Aging skin. Oral chondroitin sulfate has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in females with aging skin shows that taking a specific combination product (BioCell Collagen, BioCell Technology, LLC) containing chondroitin sulfate 200 mg, collagen peptides 600 mg, and hyaluronic acid 100 mg daily for 12 weeks reduces lines and wrinkles by about 13% when compared with baseline (28681). The validity of these findings is limited by the lack of a comparator group. It is also unclear if these improvements are due to chondroitin sulfate, other ingredients, or the combination. Furthermore, it should be noted that this study was funded by the product manufacturer.
• Aromatase inhibitor-induced arthralgia. Oral chondroitin sulfate has only been evaluated in combination with glucosamine sulfate; its effect when used alone is unclear. Details: A small open-label clinical study in postmenopausal females with early stage breast cancer shows that taking a combination of glucosamine sulfate 1500 mg and chondroitin sulfate 1200 mg in 2-3 divided doses daily for 24 weeks improves pain and symptoms associated with aromatase inhibitor-induced arthralgias when compared to baseline (89561). The validity of this finding is limited by the lack of a control group.
• Cancer. Some low-quality observational studies suggest that oral chondroitin use is not associated with a lower risk of cancer. Details: A meta-analysis of observational research has found that use of chondroitin with or without glucosamine is not associated with a lower risk of cancer when compared with no use (110625).
• Colorectal adenoma. Oral chondroitin has only been evaluated in combination with glucosamine; its effect when used alone is unclear. Details: An observational study in older adults has found that taking oral chondroitin and glucosamine is associated with a 26% reduced chance of high-risk adenoma and 10% reduced chance of conventional adenoma when compared with not using these supplements. This benefit was not seen in a subgroup of younger females (104444).
• Dry eye. It is unclear if ophthalmic chondroitin sulfate improves dry eye symptoms. Details: A small clinical study in patients with dry eye suggests that administering an ophthalmic preparation of chondroitin sulfate every two hours while awake for 2 weeks seems to improve symptoms when compared to baseline (1974). Chondroitin has also been used in combination with other ingredients. A large clinical trial in patients with mild to moderate dry eye disease shows that applying preservative-free eye drops containing chondroitin sulfate with sodium hyaluronate (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 (Systane Ultra, Alcon Laboratories) (104443). Another small clinical trial in patients with mild to moderate dry eye shows that using specific eye drops containing chondroitin sulfate and xanthan gum (PRO-148, Laboratorios Sophia) four times daily for 60 days does not improve tear stability, but might improve dry eye severity, when compared with using polyethylene/propylene glycol eye drops (Systane, Alcon Laboratories) (89591).
• Exercise-induced muscle soreness. It is unclear if oral chondroitin sulfate improves muscle soreness from exercise. Details: Preliminary clinical research in untrained males shows that taking chondroitin sulfate 1800 mg twice daily for 14 days before exercise does not reduce post-exercise muscle soreness when compared with placebo (42352). However, another small clinical study in healthy, recreationally active adults shows that a specific combination product (BioCell Collagen, BioCell Technology, LLC) containing chondroitin sulfate 300 mg, collagen peptides 900 mg, and hyaluronic acid 150 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 chondroitin sulfate, the other ingredients, or the combination.
• Gastroesophageal reflux disease (GERD). Oral chondroitin sulfate 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 the same combination agent (Esoxx by Alfa Wassermann) in addition to acid suppression with PPIs improves GERD symptom severity by 21%, heartburn by 15%, and regurgitation by 10% when compared with PPIs with a placebo (101271). This product is available in Canada as EsopH (Exzell Pharma). It is unclear if the benefit of this combination product is due to chondroitin sulfate, hyaluronic acid, or the combination. Chondroitin sulfate has also been evaluated in patients with GERD who experience extraesophageal symptoms. A small clinical study in patients reporting symptoms of cough, hoarseness, postnasal drip, sore throat, and/or throat clearing shows that taking a specific combination product (Gerdoff, SOFAR S.p.A.) containing chondroitin sulfate, hyaluronic acid, and aluminum hydroxide three times daily with omeprazole 40 mg once daily for 6 weeks does not reduce overall symptom scores, based on the Reflux Symptoms Index (RSI) score, when compared with omeprazole alone. However, it does increase the probability of treatment response, defined as a 50% or greater improvement in RSI score, by nearly 40% (109648). This product is available in Italy. It is unclear if these findings are due to chondroitin sulfate, other ingredients, or the combination.
• Gastritis. Oral chondroitin sulfate has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with gastritis shows that taking a specific liquid product (Esoxx, Alfa Wasserman Spa) containing chondroitin sulfate and hyaluronic acid four times daily for 4 weeks modestly reduces upper abdominal pain when compared with placebo (99687). It is not clear if this effect is due to chondroitin sulfate, hyaluronic acid, or the combination.
• Hyperlipidemia. Although there is interest in using oral chondroitin for hyperlipidemia, there is insufficient reliable information about the clinical effects of chondroitin for this condition.
• Interstitial cystitis. Small clinical studies suggest that intravesical chondroitin sulfate may not improve interstitial cystitis symptoms. Oral chondroitin sulfate has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Several uncontrolled, open-label studies suggest that intravesical chondroitin sulfate, with or without hyaluronic acid, improves clinical symptoms of interstitial cystitis and reduces the problems caused by symptoms in these patients (42338,42371,42373,42385,42387). However, in controlled clinical trials, intravesical chondroitin sulfate 2%, instilled weekly for 6-7 weeks, does not significantly improve symptoms when compared with a placebo solution (42473,42517). Furthermore, a meta-analysis of clinical research shows that intravesical chondroitin sulfate with hyaluronic acid does not improve pain due to interstitial cystitis better than using hyaluronic acid solution alone (97054). Oral chondroitin has been evaluated in combination with other ingredients. Preliminary clinical research shows that taking a specific product (CystoProtek, Tischon Corporation) containing glucosamine sulfate 120 mg, sodium hyaluronate 10 mg, chondroitin sulfate 150 mg, quercetin 150 mg, and rutin 20 mg, as two capsules twice daily for 12 months, reduces symptoms of interstitial cystitis by 44% to 52% (42391). It is not clear if this effect is due to chondroitin, other ingredients, or the combination.
• Kashin-Beck disease. It is unclear if oral chondroitin sulfate improves Kashin-Beck disease symptoms such as pain. Details: A small clinical study in Chinese adults with Kashin-Beck disease shows that taking chondroitin sulfate 600 mg twice daily with or without glucosamine hydrochloride 480 mg three times daily for 6 months decreases pain and stiffness when compared with placebo (42516).
• Osteoporosis. Although there is interest in using oral chondroitin for osteoporosis, there is insufficient reliable information about the clinical effects of chondroitin for this condition.
• Overall mortality. Oral chondroitin has only been evaluated in combination with glucosamine; its effect when used alone is unclear. Details: A cross-sectional observational study suggests that using oral chondroitin and glucosamine for at least one year is associated with a 27% lower incidence of overall mortality and 58% lower incidence of cardiovascular mortality when compared with not using these supplements (104445). However, this study did not clarify the forms of chondroitin and glucosamine used, or the doses, frequencies, or durations of use. Furthermore, the adults that reported glucosamine and chondroitin use also reported overall healthier lifestyle habits than those that were not taking glucosamine and chondroitin. Another observational study suggests that regular use of chondroitin with glucosamine for an average of 8 years is associated with a 30% lower risk of mortality when compared with no use. However, when these findings are adjusted for differences in age, body mass index, and comorbidities, overall mortality risk does not seem to be reduced with chondroitin and glucosamine supplementation (110626). Higher quality, prospective research is needed to clarify the relationship, if any, with overall mortality. Additionally, it is unclear if the effects on mortality are due to chondroitin, glucosamine, or the combination.
• Psoriasis. It is unclear if oral chondroitin sulfate is beneficial for reducing psoriasis disease severity. Details: A clinical study in patients with plaque psoriasis and knee osteoarthritis shows that taking chondroitin sulfate (Condrosan, CS Bio-Active, Bioibérica S.A.) 800 mg daily for 3 months does not appear to reduce the extent or severity of plaque psoriasis when compared with placebo (42463).
• Stroke. It is unclear if oral chondroitin sulfate is beneficial for reducing stroke risk. Details: An observational study in Spanish patients found that chondroitin sulfate use is associated with 23% lower odds of ischemic stroke when compared with non-use; however, the benefit was only observed in patients taking at least 800 mg for no more than one year (109643).
• Temporomandibular disorders (TMD). Oral and topical chondroitin sulfate has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A meta-analysis of two small clinical studies in patients with TMD shows that taking chondroitin sulfate 1200 mg and glucosamine sulfate 1500 mg daily for 2 months does not reduce pain or increase maximum mouth opening when compared with tramadol 50-100 mg daily (109647). Another small clinical trial in children aged 10-13 years with class II malocclusion shows that application of a specific combination gel product containing glucosamine, chondroitin, and essential oils (Jointace Gel, Vitabiotics) with an expander device twice daily for 3 months does not improve pain, tension, or temporomandibular space measures when compared with placebo (110629).
• Urinary incontinence. Although there is interest in using intravesical chondroitin for urinary incontinence, there is insufficient reliable information about the clinical effects of chondroitin for this condition.
• Urinary tract infections (UTIs). It is unclear if intravesical administration of chondroitin sulfate alone is beneficial in patients with recurrent UTIs. Most research has evaluated the effects of chondroitin sulfate in combination with hyaluronic acid, with promising results. Details: One small observational study in patients with recurrent UTIs has found that intravesical administration of 40 mL of chondroitin sulfate 0.2% weekly for 6 weeks, then every 2 weeks for 2 months, then every 3 weeks for 2 months, and finally every 6 weeks for a total treatment duration of 1 year is associated with a lower number of UTIs and urologist visits when compared with low-dose long-term antibiotic therapy (109649). Most research on the use of chondroitin sulfate for UTIs has evaluated its effects when used in combination with hyaluronic acid. Several small clinical studies and a pooled analysis of the available clinical research show that intravesical administration of 50 mL of specific solutions containing chondroitin sulfate 2% and hyaluronic acid 1.6% (iAluRil, IBSA Farmaceutici; Cystistat, Bioniche) 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 (42511,42519,89590,89594,99688). 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 (99688). More evidence is needed to rate chondroitin sulfate for these uses.

(Read more about CHONDROITIN SULFATE)

POSSIBLY EFFECTIVE

• Osteoarthritis. Oral collagen type II seems to improve stiffness, pain, and function by a small amount in patients with knee osteoarthritis, but any benefit on joint space narrowing is unclear. Details: Clinical research in patients with knee osteoarthritis shows that taking a specific collagen type II (UC-II, InterHealth Nutraceuticals, Inc.) 40 mg daily for up to 6 months reduces symptoms, such as stiffness, pain, and physical functioning, by about 20% when compared with baseline (97238,97239). Taking this product might also improve some symptoms, such as pain and stiffness, when compared with glucosamine 1500 mg plus chondroitin 1200 mg (97239). A small clinical study in patients with knee osteoarthritis and type 2 diabetes shows that taking a specific collagen type II (UC II, SEMNL Biotechnology) 40 mg daily for 3 months improves pain by 36%, compared with 5% in those receiving placebo (107466). It is unclear if taking collagen type II is more beneficial than exercise. A small clinical study in females with knee osteoarthritis shows that taking a specific collagen type II (Motilex Caps, Aspen Pharmaceutics) at an unknown dose daily for 6 weeks may improve physical functioning and pain but does not improve range of motion when compared with usual care. However, physical functioning, rigidity, and pain were not improved when compared with twice-weekly standardized exercise (110734). Collagen type II is also studied in combination with other ingredients. A small clinical study shows that taking a specific combination product (AR7 Joint Complex, Robinson Pharma) containing collagen type II, methylsulfonylmethane (MSM), cetyl myristoleate, lipase, vitamin C, turmeric, and bromelain orally for 12 weeks reduces symptoms, with 43% and 46% of patients reporting joint pain and stiffness, respectively, compared with 71% and 71% in those receiving placebo. However, the combination product does not appear to improve joint space narrowing (19314).

POSSIBLY INEFFECTIVE

• Rheumatoid arthritis (RA). Despite some conflicting results, oral collagen type II does not seem to improve symptoms of RA when compared with standard treatments. Details: Three moderately large clinical studies in patients with RA, some of whom were using disease modifying antirheumatic drugs (DMARDs), show that taking chicken collagen type II 100-2500 mcg daily or bovine collagen type II 100-500 mcg daily for 6 months does not improve clinical response rates based on American College of Rheumatology (ACR) criteria when compared with placebo (3111,44446,101718). Other clinical research in patients stabilized on oral methotrexate shows that switching to chicken collagen type II 500 mcg orally daily actually increases disease activity when compared with continued treatment with methotrexate (44456). While some clinical research in patients not taking DMARDs shows that taking chicken collagen type II 100 mcg daily may reduce symptoms, the response rates based on ACR20 and ACR50 criteria are greater for patients treated with methotrexate 10 mg weekly when compared with chicken collagen type II (44451,101717). One clinical study shows that taking low dose chicken collagen type II 20 mcg daily for 24 weeks improves clinical response according to the Paulus criteria, but not according to the ACR criteria, when compared with placebo. Other preliminary research in patients who discontinued treatment with immunosuppressants and DMARDs shows that taking chicken collagen type II 100 mcg orally daily for 1 month, followed by 500 mcg daily for 2 months, improves symptoms in some patients when compared with placebo (44454).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Back pain. Although there has been interest in using oral collagen type II for back pain, there is insufficient reliable information about the clinical effects of collagen type II for this condition.
• Gout. Although there has been interest in using oral collagen type II for gout, there is insufficient reliable information about the clinical effects of collagen type II for this condition.
• Joint pain. Oral collagen type II may modestly reduce joint pain. Details: A small clinical study in patients with joint pain due to exercise shows that taking a specific collagen type II product (UC-II, InterHealth Nutraceuticals, Inc.) 40 mg daily for 4 months may increase the duration of pain-free exercise by about 1.5 minutes when compared with baseline (101744). Another small clinical study in patients with non-arthritic knee pain shows that taking a specific chicken-derived collagen type II product (NEXT-II, Ryusendo Co.) 3.2 mg daily for 12 weeks modestly improves knee pain, stiffness, and function when compared with placebo (110733). However, it is unclear whether these results apply to patients with overweight or obesity since they were excluded from this study.
• Juvenile idiopathic arthritis (JIA). It is unclear if oral collagen type II is beneficial for JIA. Details: Some small clinical studies show that taking chicken collagen type II may improve symptoms such as swollen and tender joint scores when compared with baseline in some patients. However, the lack of a control group in these studies limits the reliability of these results (3112,101719).
• Neck pain. Although there has been interest in using oral collagen type II for neck pain, there is insufficient reliable information about the clinical effects of collagen type II for this condition.
• Pain (acute). Although there has been interest in using oral collagen type II for acute pain after trauma, there is insufficient reliable information about the clinical effects of collagen type II for this condition.
• Postoperative pain. Although there has been interest in using oral collagen type II for joint pain after surgery, there is insufficient reliable information about the clinical effects of collagen type II for this condition.
• Range of motion. It is unclear if oral collagen type II improves range of motion; study results are in conflict. Details: Small clinical studies in healthy people with joint pain due to exercise who took a specific collagen type II product (UC-II, InterHealth Nutraceuticals, Inc.) have conflicting results (101744,110732). In one study, taking 40 mg daily for 4 months increases knee extension by about 6 degrees when compared with placebo, but does not improve knee flexion (101744). However, the other study shows that taking 40 mg daily for 6 months does not improve knee extension but increases knee flexion by about 3 degrees when compared with placebo (110732). Results are similar in a small clinical study in patients with non-arthritic knee pain. In this study, taking a specific chicken-derived collagen type II product (NEXT-II, Ryusendo Co.) 3.2 mg daily for 12 weeks does not improve knee extension but increases knee flexion by about 5 degrees when compared with placebo (110733).
• Urticaria. Although there has been interest in using oral collagen type II for urticaria associated with stress, there is insufficient reliable information about the clinical effects of collagen type II for this condition.
• Uveitis. It is unclear if oral collagen type II is beneficial for uveitis. Details: Preliminary clinical research in children with uveitis associated with juvenile idiopathic arthritis shows that taking collagen type II (Colloral, AutoImmune Inc.) 60 or 540 mcg daily for 6 months does not improve ophthalmic outcomes when compared with baseline (101719). More evidence is needed to rate collagen type II for these uses.

(Read more about COLLAGEN TYPE II (NATIVE))

LIKELY EFFECTIVE

• Constipation. Rectal glycerol is beneficial in children and adults with constipation. Details: Glycerol rectal suppositories and enemas are approved by the US Food and Drug Administration (FDA) for over-the-counter use to treat occasional constipation in adults and children at least 2 years of age (15).

POSSIBLY EFFECTIVE

• Athletic performance. Oral glycerol may improve hydration during exercise, but clinical studies evaluating glycerol for improving measures of athletic performance are limited and conflicting. Details: Several clinical studies show that glycerol increases serum osmolality and improves hydration status during exercise (2475,2476,93757,93760,93761,93765). One meta-analysis, including 14 studies and 99 patients, shows that glycerol-induced hyperhydration increases body water by approximately 2.5-fold when compared with water-induced hyperhydration (93757). Also, taking glycerol along with table salt 7.5 grams per liter fluid seems to improve hydration status when compared withg glycerol alone (99162). Research regarding the effects of glycerol on thirst, comfort, temperature regulation, sweating, and heart rate is conflicting (2475,2476,93760,99162). While glycerol may improve hydration status during exercise, it is unclear whether it can improve measures of athletic performance. An early meta-analysis including a total of 36 athletes shows that taking glycerol increases endurance performance by 2.6%. Although this is a small difference, it might be considered meaningful to athletes (93757). Some small clinical studies in athletes suggest that glycerol increases endurance and time to exhaustion, with no effect on heat regulation (2475,2479,93764). However, other small studies suggest that glycerol does not reduce perceived exhaustion or improve exercise performance (2476,93760). Also, glycerol has not been shown to increase time to exhaustion in triathletes (2492). When used to improve athletic performance, glycerol is most often taken at doses of 1-1.5 gram/kg in conjunction with approximately 1.5 L of fluid, 60-120 minutes before competition, and in some cases continued during the competition (2475,93757,93760,93764).
• Ichthyosis. Topical application of a specific product containing glycerol and paraffin may improve symptoms of ichthyosis in children. The benefits of topical glycerol alone in these patients is unknown. Details: A large clinical trial in children aged 1 month to 18 years shows that applying a specific product (Dexeryl, Pierre Fabre Laboratoires) containing glycerol 15% and paraffin 10% for 4 weeks reduces symptoms of non-bullous ichthyosis by at least 50% in an additional 17% of children when compared with a placebo cream. Applying this specific product also improves pruritus by an additional 45% when compared with placebo (93756). It is unclear if these findings are due to glycerol, paraffin, or the combination.

POSSIBLY INEFFECTIVE

• Meningitis. Some clinical research suggests that oral glycerol does not reduce the risk of mortality or seizures in adults and children with bacterial meningitis, although it may reduce certain sequelae. Details: A meta-analysis of five low-quality clinical trials including 1,270 patients shows that adjunctive treatment with glycerol as an oral osmotic agent does not reduce the risk of mortality, seizures, or gastrointestinal symptoms in adults and children with acute bacterial meningitis, although it may modestly reduce the risk of deafness and residual neurological deficit in surviving children (99160). Clinical research included in the meta-analysis has used glycerol 1.5 grams/kg every 6 hours in children aged 2 months to 16 years (93762,93763).
• Prematurity. Rectal glycerol does not appear to reduce the time to enteral feeding in premature infants. Details: Glycerol is used as an enema or given by suppository to facilitate the evacuation of meconium in premature infants in order to reduce the time to enteral feeding. However, two meta-analyses of small studies in preterm infants, that include some of the same studies, show that administering glycerol suppositories does not reduce the number of days to full enteral feeds when compared with placebo or no treatment (99166,112003). However, the interpretation of these findings is limited by the heterogeneity of dosages used in the included studies.

LIKELY INEFFECTIVE

• Stroke. Intravenous glycerol may not improve mortality or symptoms in patients with acute ischemic stroke. Details: Several clinical studies show that intravenous administration of glycerol does not improve symptoms of acute stroke (2480,2481,2482,2484,2486). Additionally, one clinical study in elderly patients with acute ischemic stroke shows that while glycerol can improve initial survival, it does not reduce the risk of overall mortality when compared with placebo (2483).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Dandruff. Topical glycerol has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One clinical trial in adults with dandruff shows that applying a leave-in hair lotion containing glycerol 10%, stearic acid 2.5%, and sunflower seed oil 0.6%, 3 times weekly for 8 weeks, modestly reduces dandruff severity throughout use and for up to one week after the last application when compared with a placebo lotion. The glycerol lotion also reduced total water loss from the scalp by 8% and increased moisturization by 23% (93758). It is unclear if these findings are due to glycerol, other ingredients, or the combination.
• Dry skin. Topical glycerol has only been evaluated in combination with other ingredients for the management of dry skin associated with kidney failure; its effect when used alone is unclear. Details: One small, open-label clinical study in adults with kidney failure and moderate to severe uremic xerosis shows that applying an emulsion containing glycerol 15% and paraffin 10% twice daily for 7 days reduces the severity of xerosis when compared with a placebo emulsion. The glycerol-containing emulsion produces a treatment response in an additional 29% of patients, improves quality of life, and reduces scale density and thickness when compared with placebo (93754). It is unclear if these findings are due to glycerol, paraffin, or the combination.
• Glaucoma. Although there has been interest in using oral glycerol for glaucoma, there is insufficient reliable information about the clinical effects of glycerol for this purpose.
• Intracranial hypertension. Although there has been interest in using intravenous glycerol to reduce intracranial pressure in patients with brain tumors, central nervous system (CNS) trauma, encephalitis, idiopathic intracranial hypertension, meningitis, and Reye syndrome, there is insufficient reliable information about the clinical effects of glycerol for this purpose.
• Meniere disease. It is unclear if intravenous glycerol is beneficial in patients with Meniere disease. Details: A small, uncontrolled clinical study in adults with unilateral, intractable Meniere disease shows that intravenous administration of glycerol 10% at a dose of 0.5 grams/kg once daily for 2 consecutive days, twice monthly for 6 months, reduces the frequency of vertigo attacks and improves quality of life when compared to baseline. Patients reported an average of 3.2 vertigo attacks per month at baseline and 1.2 vertigo attacks per month after 6 months of treatment (106649). The lack of a control group limits the validity of these findings.
• Neonatal jaundice. It is unclear if rectal glycerol improves jaundice-related outcomes in premature infants. Details: A small clinical study in neonates receiving phototherapy for jaundice shows that administering glycerol suppositories has no effect on the duration of phototherapy needed for jaundice treatment, or on bilirubin levels or the rate of bilirubin decline when compared with no glycerol suppositories (99165).
• Obesity. It is unclear if oral glycerol is beneficial in patients who are overweight or obese. Details: One small clinical study in adults on a low-calorie diet shows that taking glycerol 7.5 grams before meals for 6 weeks does not increase weight loss when compared with placebo (2485).
• Otitis externa. Topical glycerol has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical study in adults with otitis externa shows that inserting ribbon gauze soaked in glycerol and ichthammol into the ear canal reduces pain and swelling as effectively as the application of antibiotic and steroid drops three times daily (93759). It is unclear if these findings are due to glycerol, ichthammol, or the combination. More evidence is needed to rate glycerol for these uses.

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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)

UNSAFE ...when used orally. 1,4-Butanediol, and the closely related products gamma-hydroxybutyrate (GHB) and gamma butyrolactone (GBL), have been linked to at least 131 serious illnesses, including 5 deaths (1318,3678,10640).

PREGNANCY AND LACTATION: UNSAFE
when used orally (1318,3678).

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LIKELY SAFE ...when used orally and appropriately. Chondroitin sulfate has been used safely in doses of up to 2000 mg daily for up to 6 years (1955,2533,13579,17732,22212,42339,42343,42348,42389,42396)(42398,42463,42477,42513,42520,42536,42541,89516,89558,89592)(89596,94360,94381,95788,95792). However, since chondroitin is often derived from bovine cartilage, historically, there was concern about contamination with diseased animal parts (1825). So far, there are no reports of disease transmission to humans due to use of contaminated chondroitin preparations. ...when used topically and appropriately as an ophthalmic viscosurgical device (OVD). Various products containing chondroitin sulfate and sodium hyaluronate have been granted approval by the US Food and Drug Administration (FDA) for use as an adjunct to cataract surgery (89436,89437).

POSSIBLY SAFE ...when used intramuscularly (10149,42397). ...when used topically as eye drops, short-term. Eye drops containing chondroitin sulfate with xanthan gum or glucosamine have been used with apparent safety four times daily for up to 3 months (89591,104443). ...when administered intravesically under the supervision of a physician (42338,42371,42373,42385,42387,42473,42511,42517,42519,109649).

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

(Read more about CHONDROITIN SULFATE)

POSSIBLY SAFE ...when used orally in doses up to 40 mg daily for up to 24 weeks (3111,44446,97238,97239,101717,101718,101744,110732).

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

(Read more about COLLAGEN TYPE II (NATIVE))

LIKELY SAFE ...when used rectally and appropriately. Glycerol rectal suppositories and enemas are approved by the US Food and Drug Administration (FDA) for over-the-counter use to treat occasional constipation (15,272). ...when used topically and appropriately as a lotion, emulsion, or humectant (15,272,93754,93758,93759,99164).

POSSIBLY SAFE ...when used orally, short-term. Glycerol has been used with apparent safety in clinical trials at doses of up to 1.5 grams/kg (2474,2475,99162).

POSSIBLY UNSAFE ...when used intravenously. While some research suggests that intravenous glycerol can be safely administered for two consecutive days twice monthly for up to 6 months (106649), in another study, hemolysis was reported in 98% of patients treated with intravenous glycerol for acute ischemic stroke (2482).

CHILDREN: LIKELY SAFE
when used rectally and appropriately. Glycerol rectal suppositories and enemas are approved by the US FDA for over-the-counter use to treat occasional constipation in children 2 years of age and older (15,272). ...when used topically and appropriately as an emulsion or humectant in children 1 month of age and older (15,272,93756).

CHILDREN: POSSIBLY SAFE
when used orally, short-term. Glycerol has been used with apparent safety in clinical trials in children 2 months to 16 years of age at doses of 1.5 gram/kg, up to a maximum dose of 25 grams, taken every 6 hours (93762,93763).

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

(Read more about GLYCEROL)

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.

(Read more about HYALURONIC ACID)

ALCOHOL (Ethanol) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = C Theoretically, alcohol may increase or decrease the therapeutic and adverse effects of 1,4-butanediol.  Details 1,4-Butanediol is metabolized to gamma-hydroxybutyrate (GHB) by hepatic alcohol dehydrogenase enzymes. Alcohol competitively inhibits alcohol dehydrogenase, which leads to higher blood levels of 1,4-butanediol and lower blood levels of GHB (1430,3678,19609,102836). The clinical effects of this change are not well understood. Most researchers believe that the pharmacologic activity of 1,4-butanediol is dependent on conversion to GHB; however, animal research shows that 1,4-butanediol may also act independently (19609). Also, in humans, concomitant use of GHB and alcohol increases the adverse effects of GHB, possibly by reducing the elimination of GHB. Concomitant use of GHB and alcohol may also cause additive respiratory and central nervous system depression (93831,102834). Therefore, concomitant use of 1,4-butanediol and alcohol may either increase or decrease the risk of adverse effects.

AMPHETAMINES Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, amphetamines may increase or decrease the therapeutic and adverse effects of 1,4-butanediol.  Details 1,4-Butanediol is metabolized to gamma-hydroxybutyrate (GHB). Although some researchers have suggested that amphetamines may antagonize the effects of GHB, this has not been well studied. Also, some case reports suggest that concomitant use might increase the risk of severe side effects, including CNS and respiratory depression (3682).

ANTICONVULSANTS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of 1,4-butanediol with certain anticonvulsants may potentiate respiratory and central nervous system (CNS) depression or increase the risk of seizures.  Details 1,4-Butanediol is metabolized to gamma-hydroxybutyrate (GHB). Concomitant use of anticonvulsants that have sedative effects with GHB may cause serious CNS and respiratory depression (102834). GHB might also reduce the effectiveness of anticonvulsants since it also can cause seizures (3682,3830,102834).

CNS DEPRESSANTS Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Theoretically, concomitant use of 1,4-butanediol with CNS depressants may potentiate respiratory and CNS depression.  Details 1,4-Butanediol is metabolized to gamma-hydroxybutyrate (GHB). Concomitant use of CNS depressants with GHB may cause serious CNS and respiratory depression (3682,102834).

DIVALPROEX SODIUM (Depakote) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of 1,4-butanediol with divalproex sodium may potentiate adverse effects.  Details 1,4-Butanediol is metabolized to gamma-hydroxybutyrate (GHB). Concomitant use of divalproex sodium with GHB may increases plasma GHB levels by approximately 25% and may increase the risk of adverse effects (102834).

NALOXONE (Narcan) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of 1,4-butanediol with naloxone may antagonize the effects of 1,4-butanediol.  Details 1,4-Butanediol is metabolized to gamma-hydroxybutyrate (GHB). Theoretically, naloxone may antagonize the effects of GHB, but anecdotally, naloxone is not effective for treating GHB poisoning (3682).

NARCOTIC DRUGS Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Theoretically, concomitant use of 1,4-butanediol with narcotic drugs may potentiate respiratory and central nervous system (CNS) depression. 1,4-Butanediol is metabolized to gamma-hydroxybutyrate (GHB).  Details Concomitant use of narcotic drugs with GHB may cause serious CNS and respiratory depression (3682,3679,19610,102834). In one case report, concurrent use of GHB and heroin was fatal (5807).

RITONAVIR (Norvir) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Concomitant use of 1,4-butanediol with ritonavir may potentiate adverse effects.  Details 1,4-Butanediol is metabolized to gamma-hydroxybutyrate (GHB). Concomitant use of a small dose of GHB with the antiretroviral drugs ritonavir and saquinavir reportedly caused a near-fatal reaction, likely due to inhibition of GHB metabolism (1431).

SAQUINAVIR (Fortovase, Invirase) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Concomitant use of 1,4-butanediol with saquinavir may potentiate adverse effects.  Details 1,4-Butanediol is metabolized to gamma-hydroxybutyrate (GHB). Concomitant use of a small dose of GHB with the antiretroviral drugs ritonavir and saquinavir reportedly caused a near-fatal reaction, likely due to inhibition of GHB metabolism (1431).

TOPIRAMATE (Topamax) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Concomitant use of 1,4-butanediol with topiramate may potentiate adverse effects.  Details 1,4-Butanediol is metabolized to gamma-hydroxybutyrate (GHB). Concomitant use of topiramate with GHB may increases blood levels of GHB. In one case report, a patient regularly taking GHB 4.5 grams twice nightly was hospitalized after initiating treatment with topiramate 25 mg daily. Symptoms included confusion, muscle jerking, miosis, and coma. Plasma levels of GHB were 2.5-fold higher than when GHB was given alone. Potential mechanisms might include decreased GHB breakdown, increased absorption, and/or increased activity (93834).

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WARFARIN (Coumadin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Unlikely •  Level of Evidence = D Taking chondroitin in combination with glucosamine might increase the anticoagulant effects of warfarin. However, the effect of chondroitin alone is unclear.  Details There have been multiple reports of increased international normalized ratio (INR) in patients taking warfarin with glucosamine, with or without chondroitin. The lack of reports with chondroitin alone seem to suggest that the interactions occurring in these reports may have been due to glucosamine. In two individual case reports, glucosamine/chondroitin combinations were associated with a significant increase in INR in patients previously stabilized on warfarin (11389,16130). Additionally, 20 voluntary case reports to the US Food & Drug Administration (FDA) have linked glucosamine plus chondroitin with increased INR, bruising, and bleeding in patients who were also taking warfarin (16130). There have also been 20 additional case reports to the World Health Organization (WHO) that link glucosamine alone, without chondroitin, to increased INR in patients taking warfarin (16131).

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General ...1,4-butanediol is generally considered unsafe for any use. Any benefits do not outweigh the risks of toxicity.
Most Common Adverse Effects:
Orally: Agitation, amnesia, anxiety, bradycardia, chest tightness, confusion, hallucinations, nausea, tremor, vomiting.
Serious Adverse Effects (Rare):
Orally: Cardiac arrest, coma, death, respiratory depression.

Cardiovascular ...Orally, 1,4-butanediol and its metabolite, gamma-hydroxybutyrate (GHB), can cause chest tightness, bradycardia, and cardiac arrest (1318,3678,3679,6016,10640,37465,10658,93820).

Gastrointestinal ...Orally, 1,4-butanediol can cause nausea and vomiting, diarrhea, and fecal incontinence (1318,3678,3679,10640,37465).

Neurologic/CNS ...Orally, 1,4-butanediol is metabolized to gamma-hydroxybutyrate (GHB), and its psychoactive effects are primarily due to GHB (102837). 1,4-Butanediol also causes similar CNS toxic effects to GHB, including amnesia, combativeness, confusion, agitation, coma, seizures, and death (1318,3678,3679,10640,37465). After 1,4-butanediol overdoses, sedation gradually increases, consistent with gradual conversion to GHB (102837). 1,4-Butanediol overdose can also present with features suggesting toxic alcohol poisoning (102837). Neurologic and CNS withdrawal symptoms of 1,4-butanediol, GHB, and GBL include insomnia, tremor, anxiety, hallucinations, and delirium (1430,10375,10640).

Pulmonary/Respiratory ...Orally, 1,4-butanediol, especially in overdose, can cause breathing problems and respiratory depression that can require intubation (1318,3678,3679,10640,37465).

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General ...Orally and topically, chondroitin sulfate is generally well tolerated. Intramuscular and ophthalmic use also seems to be well tolerated.
Most Common Adverse Effects:
Orally: Abdominal pain, bloating, constipation, diarrhea, heartburn, nausea.
Serious Adverse Effects (Rare):
Orally: There have been rare reports of hepatotoxicity.

Cardiovascular ...One case of congestive heart failure and another case of myocardial infarction has been possibly attributed to use of glucosamine hydrochloride and chondroitin sulfate (13579,42477). Also, a case of mesenteric occlusion in one patient was considered possibly related to treatment with chondroitin sulfate and glucosamine (89520).

Dermatologic ...Orally, chondroitin sulfate has been associated with skin symptoms, such as eyelid edema, lower limb edema, alopecia, and skin rash (42513). Combinations of chondroitin sulfate along with glucosamine hydrochloride may also be associated with rash, water retention around eyes and scars, and hives on face, chest, torso, and legs when taken orally (42436,110628). A case of photosensitization that was reproducible with rechallenge has been reported following treatment with oral glucosamine-chondroitin products. However, it is not clear if this effect was due to glucosamine, chondroitin sulfate, or contaminants in the product (10408). A case of rash following treatment with intravesical chondroitin sulfate has been reported to be possibly related to the product (42385).

Gastrointestinal ...Orally, chondroitin might cause nausea, bloating, abdominal pain, diarrhea, constipation, vomiting, dyspepsia, and epigastric burning (42396,42436,42541,89561,110628,111647).

Genitourinary ...Intravesical chondroitin sulfate has been associated with cases of vulvar burning, vaginitis, urinary tract infection (UTI), dysuria, pelvic pain, and other bladder symptoms, such as increased frequency, urgency, or incontinence. However, these effects might be due to catheterization rather than chondroitin sulfate (42385,42387,42473).

Hematologic ...Concern has been expressed about possible anticoagulant activity of oral chondroitin sulfate. However, hematological changes have not occurred in patients taking chondroitin sulfate in clinical trials (760).

Hepatic ...Although relatively uncommon, combinations of glucosamine and chondroitin sulfate have been associated with acute liver injury that mimics autoimmune hepatitis. Two cases of elevated aminotransferase levels have been reported for patients taking glucosamine (form unspecified) and chondroitin sulfate at recommended doses. Aminotransferase levels, which were increased by four- to seven-fold, returned to normal following discontinuation of treatment (89515). Another case of abdominal pain, jaundice, fatigue, and elevated liver enzymes has been reported for a patient who used chondroitin sulfate (Condrosulf) for 2 years followed by a combination of glucosamine sulfate and chondroitin sulfate (Vita Mobility Complex) for 8 weeks. The patient required maintenance treatment with azathioprine to remain in remission (89518). A case of acute cholestatic hepatitis due to Glucosamine Forte, which contains glucosamine hydrochloride, chondroitin sulfate, Devil's claw, and shark cartilage, has been reported (89522). It is unclear whether these adverse events were related to chondroitin sulfate, other ingredients, or the combination.

Musculoskeletal ...Orally, chondroitin has been associated with musculoskeletal and connective-tissue events and disorders (13579,42520,95516).

Neurologic/CNS ...Rare cases of headache have been reported following treatment with products containing a combination of oral chondroitin sulfate and glucosamine hydrochloride or glucosamine sulfate (42436,89561). It is unclear if this effect was due to chondroitin, glucosamine, or the combination.
Patients should adhere to product directions when using chondroitin sulfate products that contain manganese. When taken at doses slightly higher than the recommended dose, these products can sometimes supply greater than the tolerable upper limit (UL) for manganese of 11 mg per day. Ingestion of more than 11 mg per day of manganese might cause significant central nervous system toxicity (7135).

Ocular/Otic ...A case of bilateral pinna chondritis (inflammation of the cartilage of the external ear) has been reported for a patient who received supplements containing glucosamine and chondroitin sulfate (42503).

Pulmonary/Respiratory ...A case of asthma exacerbation has been reported occurred following use of an oral glucosamine and chondroitin sulfate combination product (10002).

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General ...Orally, collagen type II seems to be well tolerated.
Most Common Adverse Effects:
Orally: Abdominal pain, constipation, nausea, and vomiting.

Cardiovascular ...Orally, one incident of mild hypertension was reported as being possibly related to collagen type II in a clinical trial of children (101719).

Dermatologic ...Orally, collagen type II might cause itching. In two cases, the itching was associated with skin eruption (44451,101717,101719).

Gastrointestinal ...Orally, the most common adverse effects of collagen type II reported in clinical studies are gastrointestinal and include constipation, nausea, vomiting, and abdominal pain. These occurred in up to 7% of patients taking collagen type II (44451,97238,97239,101717,101719). Anorexia was also reported, but this was much less common (44451).

Hematologic ...Orally, one incident each of blood in urine and a decrease in white blood cell count were reported for patients taking collagen type II in clinical research (101717).

Hepatic ...Orally, liver function abnormalities, including elevated transaminase levels, have been reported in some clinical research, but this is uncommon (3111,44451,101717).

Neurologic/CNS ...Orally, headache, dizziness, and insomnia have been reported for patients taking collagen type II in clinical studies, but these events are uncommon (44451,97238,97239,101717).

Renal ...Orally, one case of mild proteinuria was reported as being possibly related to use of collagen type II in a clinical trial of children (101719).

Other ...Orally, edema occurred in two patients taking collagen type II in clinical research (101717).

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General ...Orally, rectally, and topically, glycerol seems to be well tolerated. Intravenously, glycerol may be unsafe.
Most Common Adverse Effects:
Orally: Bloating, diarrhea, nausea, vomiting, dizziness, and headache.
Topically: Burning, irritation, and pruritus.
Intravenously: Hemolysis in patients with acute ischemic stroke.

Dermatologic ...Topically, glycerol has been reported to cause burning, irritation, and pruritus (93754,93756). Rectally, the regular administration of glycerol 50% enemas has been reported to cause generalized urticaria in at least two patients; in both patients, symptoms resolved after discontinuation (110019,110025).

Gastrointestinal ...Orally, glycerol can cause bloating, nausea, vomiting, thirst, and diarrhea (15,2475).

Hematologic ...Intravenously, glycerol has been reported to caused hemolysis in people treated for acute ischemic stroke (2480,2482).

Neurologic/CNS ...Orally, glycerol can cause mild headache and dizziness (15,2475).

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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).

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