Hydration Restore by Adrian London

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Dental plaque. It is unclear if oral Ascophyllum nodosum is beneficial in patients with dental plaque. Details: A small crossover study in adults with moderate to heavy calculus formation shows that taking a specific brand of Ascophyllum nodosum capsules (ProDen PlaqueOff, SDC Swedencar eAB) 500 mg daily for 6 months reduces the buildup of supragingival calculus by 52% when compared with placebo. The buildup of plaque was reduced by 19% in males, but was not reduced in females, when compared with placebo (94996).
• Gastroesophageal reflux disease (GERD). Although there has been interest in using oral Ascophyllum nodosum for GERD, there is insufficient reliable information about the clinical effects of Ascophyllum nodosum for this purpose.
• Gingivitis. It is unclear if oral Ascophyllum nodosum is beneficial in patients with dental plaque. Details: A small crossover study in adults with moderate to heavy calculus formation shows that taking a specific brand of Ascophyllum nodosum capsules (ProDen PlaqueOff, SDC Swedencar eAB) 500 mg daily for 6 months does not reduce gingivitis when compared with placebo (94996).
• Impaired glucose tolerance (prediabetes). Oral Ascophyllum nodosum has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in adults with prediabetes that are overweight or obese shows that taking a specific product (InSea2, InnoVactiv Inc.) containing 500 mg of Ascophyllum nodosum and Fucus vesiculosus extracts daily for 12 weeks reduces postprandial blood glucose but does not improve fasting blood glucose, glycated hemoglobin (HbA1c), body weight, lipids, or blood pressure when compared with placebo (110560).
• Inflammatory bowel disease (IBD). Although there has been interest in using oral Ascophyllum nodosum for IBD, there is insufficient reliable information about the clinical effects of Ascophyllum nodosum for this purpose.
• Iodine deficiency. It is unclear if oral Ascophyllum nodosum is beneficial in patients with iodine deficiency. Details: Ascophyllum nodosum contains iodine, and there is interest in its use for patients with iodine deficiency. A small clinical study in females with iodine insufficiency shows that taking a specific brand of Ascophyllum nodosum capsules (Napiers Hebridean Seagreens (NaHS), Seagreens Ltd) 500 mg daily for 14 days increases urinary iodine excretion by almost three-fold and increases thyroid stimulating hormone levels by 36% when compared with baseline (94997). The validity of these findings is limited by the lack of a control group.
• Metabolic syndrome. Oral Ascophyllum nodosum has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Observational research in adults with one or more components of metabolic syndrome has found that taking a specific combination product (Gdue, Aesculapius) containing extracts of Ascophyllum nodosum and Fucus vesiculosus in a 95:5 ratio along with chromium picolinate two to three times daily with meals for around 6 months is associated with reductions in body weight by 7.3 kg, waist circumference by 7.5 cm, fasting blood glucose by 16 mg/dL, glycated hemoglobin (HbA1c) by 0.55%, systolic blood pressure by 7 mmHg, diastolic blood pressure by 4 mmHg, low-density lipoprotein (LDL) cholesterol by 18 mg/dL, and 10-year cardiovascular risk scores by 1.8% when compared to baseline (110559). It is unclear if these effects are due to Ascophyllum nodosum, Fucus vesiculosus, or the combination. Further, the validity of these findings is limited by a lack of control group.
• Obesity. Oral Ascophyllum nodosum has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in adults with prediabetes that are overweight or obese shows that taking a specific product (InSea2, InnoVactiv Inc.) containing 500 mg of Ascophyllum nodosum and Fucus vesiculosus extracts daily for 12 weeks does not reduce body weight, body mass index (BMI), body fat, lipids, blood pressure, or measures of glycemic control when compared with placebo (110560).
• Peptic ulcers. Although there has been interest in using oral Ascophyllum nodosum for peptic ulcers, there is insufficient reliable information about the clinical effects of Ascophyllum nodosum for this purpose. More evidence is needed to rate Ascophyllum nodosum for these uses.

(Read more about ASCOPHYLLUM NODOSUM)

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 EFFECTIVE

• Dental caries. Using xylitol-containing products topically in the mouth seems to reduce the incidence of cavities. Details: Use of xylitol-containing products such as foods, chewing gum, candies, soluble dragees, and toothpaste that provide 1-20 grams of xylitol per day can marginally reduce the incidence of cavity formation in both adults and children (6815,6819,6822,95110,95114,95116,95117,95125,113324). Xylitol products appear to be more effective than products containing sorbitol for preventing cavity formation (6822,95690,113324). A scientific council of the American Dental Association states that chewing gum containing xylitol for 10-20 minutes after meals, or using lozenges providing xylitol 5-8 grams in divided doses daily, can reduce the incidence of coronal caries in adults and children 5 years or older (95690). However, these recommendations are based on only weak evidence. There is not enough evidence to recommend xylitol products for preventing caries in children under the age of 5 years (95124,95690,112858). In 2008, the US Food and Drug Administration (FDA) authorized a health claim for products containing xylitol. These products can state that although frequently eating foods high in sugars and starches as between-meal snacks can promote tooth decay, xylitol used to sweeten food does not promote tooth decay and may reduce the risk of dental caries (102364).

POSSIBLY EFFECTIVE

• Otitis media. Using xylitol-containing products topically in the mouth on a daily basis seems to reduce the risk of otitis media in preschool-aged children. Details: Giving a total daily dose of xylitol 8.4-10 grams as a chewing gum, lozenge, or syrup up to 5 times a day after meals to preschool children seems to reduce the risk of acute otitis media by about 25% when compared with a control containing sucrose alone or with low dose xylitol (6816,6817,95112). Xylitol gum and xylitol lozenges appear to be similarly effective for this indication; xylitol syrup might be slightly less effective than xylitol gum (95111,95112). Some research suggests that xylitol may also reduce the usage of antibiotics for acute otitis media, although results are conflicting (6816,6817,95112). However, a more recent clinical trial disagrees with these findings and shows that taking a syrup containing xylitol up to 5 times daily for 6 months does not reduce the risk of acute otitis media when compared with a control syrup containing sorbitol (113319). The reason for this discrepancy is unclear. However, the number of otitis media episodes was extremely low overall, with no episodes in the many children recruited during the COVID-19 pandemic. In addition, the average xylitol intake in this study was 3.7 grams daily, much lower than in the previous studies. However, xylitol 8.4-10 grams daily, administered at the onset of symptoms of an acute respiratory infection, does not seem to prevent acute otitis media (3846,95112). It is unclear whether xylitol reduces the risk of acute otitis media in children with recurrent acute otitis media. Limited clinical research shows that xylitol as gum or lozenges does not appear to reduce the risk of acute otitis media among otitis-prone healthy children (95112). However, preliminary clinical research in children aged 1-4 years shows that using a xylitol nasal spray 2-3 times daily for 3 months modestly reduces the number of episodes, as well as the number of episodes treated with systemic or topical antibiotics, when compared to the 3-month period before treatment (113323).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Coronavirus disease 2019 (COVID-19). It is unclear if intranasal xylitol is beneficial in patients with COVID-19. Details: Preliminary clinical research in adult outpatients with a positive COVID-19 test who are receiving standard treatment for symptoms lasting less than 3 days shows that using a nasal spray containing xylitol 11%, sodium chloride 0.85%, and grapefruit seed extract 0.2% in water, 2 sprays in each nostril every 3 hours while awake for 72 hours, then every 6 hours for a total of 14 days, does not affect time to symptom resolution or incidence of hospitalization when compared with a normal saline spray (109996).
• Cystic fibrosis. It is unclear if inhaled xylitol is beneficial in patients with cystic fibrosis. Details: Preliminary clinical research in patients hospitalized for an exacerbation of cystic fibrosis shows that administering 5 mL of xylitol 15% solution through a nebulizer twice daily for 2 weeks does not improve lung function, the density of sputum microbes, or quality of life when compared with hypertonic saline (103888).
• Dental plaque. There is some evidence that chewing xylitol gum reduces oral plaque in adults. It is unclear if topical xylitol solution helps to reduce dental plaque in children or adolescents. Details: A meta-analysis of 8 studies in adults shows that chewing sugar-free gum containing xylitol, sorbitol, or maltitol reduces oral plaque levels when compared with chewing sugar-containing gum or not chewing any gum (109997). One small clinical study in children aged 2-5 years shows that applying 40% xylitol solution using gauze once daily for 6 months does not suppress Streptococcus mutans count or reduce plaque accumulation when compared to baseline (95119). Conversely, a small clinical study in adolescents aged 14-17 years shows that rinsing with a solution containing xylitol, lysozyme, sea salt, and menthol (H2Ocean Sea Salt Mouthwash) twice daily for 3 months seems to reduce dental plaque and S. mutans levels when compared to baseline (105979). The validity of this finding is limited due to a lack of statistical comparison to the placebo group. Additionally, it is unclear if any effects are due to xylitol, other ingredients, or the combination.
• Dry mouth. Oral xylitol has only been evaluated in combination with maltitol; its effect when used alone is unclear. Details: One small open-label clinical study in patients with gastroesophageal reflux disease who are experiencing dry mouth while taking omeprazole 40 mg daily shows that taking specific tablets (Xeros Dentaid, Dentaid) containing xylitol 422 mg and malic acid 28.6 mg 3 times daily after meals for 6 months seems to reduce the incidence of dry mouth and increase the buffering capacity of saliva when compared with no additional treatment (105982).
• Gingivitis. Topical xylitol has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study of patients with gingivitis shows that brushing with a toothpaste containing a combination of xylitol, extra virgin olive oil, and betaine anhydrous daily for 4 months decreases gingival bleeding and improves markers associated with gingival health when compared with placebo and commercial toothpaste (111372).
• Gulf war syndrome. It is unclear if intranasal xylitol is beneficial for improving respiratory symptoms in adults with Gulf war syndrome. Details: A small clinical study in patients with chronic rhinosinusitis and Gulf war syndrome shows that administering xylitol 5% solution intranasally via neti pot twice daily for 26 weeks in addition to standard care modestly improves nasal symptoms when compared with standard treatment alone. However, the improvement did not reach the pre-specified measure of clinical significance (105981).
• Hematopoietic stem cell transplant (HSCT). It is unclear if topical xylitol dental wipes help to prevent infections after HSCT. Details: One small open-label clinical trial in children and young adults undergoing HSCT shows that adding xylitol dental wipes 0.7 grams daily to standard care for oral hygiene, starting with ablative chemotherapy and continuing 28 days post-transplant, reduces the risk for bloodstream infections when compared with standard care alone. For every 4 patients treated with xylitol, one bloodstream infection was prevented (103890).
• Intranasal surgery. It is unclear if nasal irrigation with xylitol solution improves pain and obstruction after intranasal surgery. Details: Preliminary clinical research in patients undergoing endonasal endoscopic surgery shows that nasal irrigation with 60 mL of solution containing xylitol 1 gram in each nostril three times daily for 30 days, starting the second day after surgery, reduces pain and nasal obstruction when compared with saline nasal irrigation (103889).
• Obesity. It is unclear if oral xylitol is beneficial for obesity. Details: A small clinical trial in adults with obesity shows that taking xylitol daily for 5 weeks does not reduce abdominal fat or lipid levels or have beneficial effects on glucose tolerance or liver health when compared with no treatment. The xylitol dose in this study was 8 grams daily for 2 days, followed by 8 grams twice daily for 3 days, and then 8 grams 3 times daily for the remaining period (113320).
• Pain (acute). It is unclear if topical xylitol is beneficial for reducing dental injection pain in children. Details: A small clinical trial in children aged 5-7 years shows that applying xylitol 30% solution to the tongue for 2 minutes prior to topical anesthetic and dental injection modestly reduces pain associated with the injection compared with distilled water. Also, the xylitol solution was as effective as a 30% sucrose solution (113321).
• Postoperative ileus. It is unclear if chewing xylitol gum can reduce the development of postoperative ileus after various types of surgery. Details: An unblinded clinical study in adults undergoing colorectal resection for colon cancer shows that chewing xylitol gum for 15 minutes three times daily, starting on the first postoperative day, reduces the time to first flatus from 53 hours to 39 hours and the time to first defecation from 78 hours to 55 hours when compared with standard care alone (109998). A small clinical study in patients undergoing a Cesarean section shows that chewing xylitol gum for 15 minutes every 2 hours for 8-12 hours, starting 2 hours after surgery, does not reduce the time to first bowel sounds or first feeling of hunger when compared with chewing non-xylitol gum or not chewing any gum. The time to first defecation is 38, 44, and 45 hours, respectively, while times to hospital discharge are 46, 50, and 52 hours, respectively; it is unclear if these differences are statistically significant (109999).
• Rhinosinusitis. Small clinical studies suggest that intranasal rinses with xylitol solution may modestly improve nasal symptoms in patients with chronic rhinosinusitis. Details: Two small clinical studies in patients with chronic rhinosinusitis shows that nasal irrigation using 240 mL of solution containing xylitol 12 grams daily for up to 30 days reduces symptoms better than nasal irrigation with saline (95115,95122). Another small clinical study in patients with chronic rhinosinusitis and Gulf war syndrome shows that administering xylitol 5% solution intranasally via neti pot twice daily for 26 weeks in addition to standard care modestly improves nasal symptoms when compared with standard treatment alone. However, the improvement did not reach the pre-specified measure of clinical significance (105981).
• Upper respiratory tract infection (URTI). Although there is interest in using topical xylitol for URTI prevention in children, there is insufficient reliable information about the clinical effects of xylitol for this purpose. More evidence is needed to rate xylitol for these uses.

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POSSIBLY SAFE ...when used orally, short-term. Ascophyllum nodosum dried powder has been used with apparent safety at a dose of up to 500 mg daily for up to 6 months (94996,94997,103900). However, marine products such as Ascophyllum nodosum are known to accumulate heavy metals such as arsenic (94997,94999). Some supplement products are prospectively analyzed to confirm a lack of contaminants and that heavy metal levels are below threshold (94997).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using amounts greater than those found in food.

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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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LIKELY SAFE ...when used orally in amounts commonly found in foods. Xylitol is an approved food additive in the US (17915).

POSSIBLY SAFE ...when used orally and appropriately in medicinal amounts as a chewing gum, candy, lozenge, toothpaste, or mouth rinse. Xylitol has been used with apparent safety in doses of 20-53 grams daily for up to 3 years (6815,6819,6821). ...when used as nasal irrigation 1-3 times daily for up to 30 days (95115,95122,103889,105981). ...when inhaled via nebulizer. 5 mL of xylitol 15% solution has been used with apparent safety twice daily for up to 2 weeks (103888).

POSSIBLY UNSAFE ...when used orally in very high doses, long-term. There is some concern that very high doses for extended periods of use can induce tumor growth (6815,6820). However, this effect has not yet been demonstrated in humans.

CHILDREN: POSSIBLY SAFE
when used orally and appropriately in medicinal amounts as a chewing gum, candy, lozenge, toothpaste, or mouth rinse. Xylitol has been used with apparent safety in doses up to 20 grams daily for up to three years (6815,6819,113319).

PREGNANCY AND LACTATION:
There insufficient reliable information available about the use of xylitol in medicinal amounts during pregnancy and lactation; avoid using.

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AMIODARONE (Cordarone) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, combining Ascophyllum nodosum with amiodarone might cause excessively high iodine levels.  Details Ascophyllum nodosum contains iodine (94997,95000,95102), although the bioavailability of iodine from Ascophyllum nodosum is lower than that of potassium iodide (94997). Amiodarone contains 37.3% iodine and can increase iodine levels. Concomitant use might increase the risk of having excessive iodine levels and adversely affecting thyroid function (7135,17574). Monitor thyroid function.

ANTITHYROID DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Due to its iodine content, Ascophyllum nodosum might alter the effects of antithyroid drugs.  Details Ascophyllum nodosum contains iodine (94997,95000,95102), although the bioavailability of iodine from Ascophyllum nodosum is lower than that of potassium iodide (94997). Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking Ascophyllum nodosum while using antithyroid drugs could alter the effects of the antithyroid drugs (17574).

THYROID HORMONE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.  Details Ascophyllum nodosum contains iodine (94997,95000,95102), although the bioavailability of iodine from Ascophyllum nodosum is lower than that of potassium iodide (94997). Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking Ascophyllum nodosum while using thyroid hormone could alter the effects of thyroid hormone (17574).

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General ...Orally, Ascophyllum nodosum seems to be generally well-tolerated.

Endocrine ...Orally, taking Ascophyllum nodosum powder 500 mg daily for 14 days has been reported to cause elevated levels of thyroid stimulating hormone (TSH) in 2 of 22 women in a clinical trial. The powder contained 356 mcg iodine per 500 mg. Levels of free thyroxine (T4) were unaffected (94997).

Gastrointestinal ...Orally, Ascophyllum nodosum has been reported to cause stomach discomfort in one clinical trial (94996).

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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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General ...Orally, xylitol is generally well tolerated in food amounts, although it may cause gastrointestinal discomfort at high doses. Topically, xylitol seems to be well tolerated.
Most Common Adverse Effects:
Orally: With high doses (30-40 grams), bowel sounds, diarrhea, flatulence.
Topically: Stinging of mucous membranes.

Cardiovascular ...Population research in adults at high risk for cardiovascular events suggests that the highest fasting blood levels of xylitol are associated with a 57% increased risk of major adverse cardiovascular events and a decreased incidence of event-free survival compared with lower levels (113318). As fasting blood levels are unrelated to consumption, it is unclear whether xylitol supplementation increases the risk of a major adverse cardiovascular event in this or any population. In healthy adults, a single dose of xylitol 30 grams increases blood levels of xylitol to levels capable of stimulating platelet aggregation in vitro (113318).

Endocrine ...Orally, high doses of xylitol can increase the risk of hyperuricemia. In a small study in healthy adults, taking a single dose of xylitol 35 grams in water increases levels of uric acid, while lower doses of xylitol did not have this effect (105980). Intravenous infusion of high doses of xylitol has been associated with hyperuricemia and acidosis, including lactic acidosis (6815).

Gastrointestinal ...Orally, acute administration of large amounts of xylitol (24 to 40 grams) can cause osmotic diarrhea, nausea, and flatulence (9,112857,113320). However, if the dose is increased gradually, tolerance to this effect can occur and prevent development of diarrhea and flatulence (9). Intranasally, flatulence and abdominal discomfort have been reported rarely (113323).

Hepatic ...Intravenous infusion of high doses has been associated with changes in liver function enzymes (6815).

Immunologic ...There are various cases of suspected allergic reactions to xylitol. In one case, an anaphylactic reaction to xylitol was reported in a 2-year-old. The allergy was confirmed based on a skin-prick test and basophil activation test (100173).

Pulmonary/Respiratory ...Following use of xylitol in nasal irrigation, minor stinging in the nose has been reported (95122,105981). Intranasally, a minor nosebleed and mild cough have been reported rarely (113323).

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