{"ok":true,"entry":{"slug":"biotin","kind":"supplement","name":"biotin","aliases":["vitamin B7","vitamin H"],"brands_sg":["California Gold Nutrition","NOW Foods","NeoCell","21st Century","Natrol"],"class":"vitamin","tags":["skin-hair"],"use_for":"hair, skin, nail claims: limited evidence · metabolism","use_after":"no timing rule published","use_duration":null,"take_with":"raw egg white (avidin) blocks uptake · cooking denatures it","pros":["ai is 30 mcg a day; deficiency is rare","no ul — no human toxicity seen at 10–50 mg/day","brittle nails: 3 small studies, no placebo group"],"cons":["hair claims rest on case reports in children only","high doses give false lab results (thyroid, troponin)","hsa cap 0.9 mg/day · iherb lists 5,000–10,000 mcg doses"],"dose_note":"ai is 30 mcg a day for adults 19+ (35 mcg when breastfeeding); no ul has been set because there is no evidence of toxicity in humans — studies found no adverse effects at 10–50 mg/day; the small nail studies used 2.5 mg/day; hsa's general-adult limit for health supplements in singapore is 0.9 mg (900 mcg) a day, far below the 5,000–10,000 mcg products common on iherb sg","dosage":{"ul":null,"unit":"mcg","fda_dv":"30 mcg","rda_ai":"30 mcg (AI, adults 19+)","ul_status":"none_established","population":"general adult","hsa_max_daily":"0.9 mg (900 mcg)"},"ul_status":"none_established","sg_class":null,"cautions":["any blood test coming up (thyroid, troponin, vitamin d) — high-dose biotin can give falsely high or low results; fda says doctors should ask about biotin use","on anticonvulsants (carbamazepine, phenytoin, phenobarbital, primidone) — serum biotin runs lower; ask your doctor","pregnant or breastfeeding — marginal deficiency is common even with normal intakes; clinical meaning unclear","heavy alcohol use — absorption is inhibited; low plasma biotin in 15% of people with chronic alcoholism"],"clashes":[{"src":["nih_ods_biotin_labtests"],"note":"biotin-streptavidin tests read falsely high or low; interference seen within 24 h of a single 10 mg dose","with":"laboratory immunoassays (thyroid hormones, troponin, 25-oh vitamin d)"},{"src":["nih_ods_biotin_interactions"],"note":"≥1 year of treatment linked to significantly lower serum biotin","with":"anticonvulsants (carbamazepine, primidone, phenytoin, phenobarbital)"}],"sources":[{"id":"nih_ods_biotin_intake","url":"https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/","label":"NIH ODS — Biotin Fact Sheet for Health Professionals (updated January 10, 2022; read via archive.org capture, see verify_notes) — Table 1 AIs, Introduction, Biotin Deficiency","quote":"19+ years 30 mcg 30 mcg 30 mcg 35 mcg … a cofactor for five carboxylases … that catalyze critical steps in the metabolism of fatty acids, glucose, and amino acids … Biotin deficiency is rare","accessed":"2026-08-27"},{"id":"nih_ods_biotin_evidence","url":"https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/","label":"NIH ODS — Biotin Fact Sheet for Health Professionals (updated January 10, 2022; read via archive.org capture, see verify_notes) — Biotin and Health — Hair, nail, and skin health","quote":"these claims are supported, at best, by only a few case reports and small studies … three small studies that did not include a placebo group … Only case reports are available … and these reports were only in children","accessed":"2026-08-27"},{"id":"nih_ods_biotin_safety","url":"https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/","label":"NIH ODS — Biotin Fact Sheet for Health Professionals (updated January 10, 2022; read via archive.org capture, see verify_notes) — Health Risks from Excessive Biotin","quote":"The FNB was unable to establish ULs for biotin because there is no evidence in humans that biotin is toxic at high intakes. Several studies have found no adverse effects of 10–50 mg/day biotin","accessed":"2026-08-27"},{"id":"nih_ods_biotin_absorption","url":"https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/","label":"NIH ODS — Biotin Fact Sheet for Health Professionals (updated January 10, 2022; read via archive.org capture, see verify_notes) — Sources of Biotin — Food; Dietary supplements","quote":"Dietary avidin, a glycoprotein in raw egg whites, binds tightly to dietary biotin and prevents biotin’s absorption … Cooking denatures avidin … The absorption rate of oral, free biotin is 100%, even when people consume pharmacologic doses of up to 20 mg/day","accessed":"2026-08-27"},{"id":"nih_ods_biotin_labtests","url":"https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/","label":"NIH ODS — Biotin Fact Sheet for Health Professionals (updated January 10, 2022; read via archive.org capture, see verify_notes) — Interactions with Laboratory Tests","quote":"Even a single 10 mg dose of biotin has interfered with thyroid function tests administered within 24 hours … a patient with a high intake of supplemental biotin died following a troponin test … that gave a falsely low result","accessed":"2026-08-27"},{"id":"nih_ods_biotin_interactions","url":"https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/","label":"NIH ODS — Biotin Fact Sheet for Health Professionals (updated January 10, 2022; read via archive.org capture, see verify_notes) — Interactions with Medications — Anticonvulsants; Groups at Risk","quote":"anticonvulsant treatment for at least 1 year was associated with significantly lower serum biotin levels … alcohol inhibits the absorption of biotin … At least a third of pregnant women develop marginal biotin deficiency in spite of normal biotin intakes","accessed":"2026-08-27"},{"id":"fda_dv","url":"https://www.fda.gov/food/nutrition-facts-label/daily-value-nutrition-and-supplement-facts-labels","label":"FDA — Daily Value on the Nutrition and Supplement Facts Labels, Reference Guide: Daily Values for Nutrients (content current as of 03/05/2024)","quote":"DVs are the recommended amounts of nutrients to consume or not to exceed each day … Biotin … 30mcg","accessed":"2026-08-27"},{"id":"hsa_hs_guidelines","url":"https://file.go.gov.sg/hsa-hs-guidelines.pdf","label":"HSA Singapore — Health Supplements Guidelines GL-CHPB-3-001 Rev. No. 020, January 2026 — clause 4.8, Table 4 Vitamins Limits + List of Health Claims","quote":"HS for use by the general adult population should not contain vitamins and minerals exceeding the stipulated limits … Biotin 0.9mg … Help maintain healthy hair, nail, mucous membranes and/or skin • Biotin","accessed":"2026-08-27"},{"id":"hsa_prohibited","url":"https://file.go.gov.sg/hsa-chp-prohibited-restricted-ing-guidelines.pdf","label":"HSA Singapore — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines GL-CHPB-1-012 Rev. No. 001, October 2025 — Annex A row 13","quote":"13. Biotin Restricted use in HS and TM … When for oral use by general adult population, the maximum recommended daily dose should not provide more than 0.9mg","accessed":"2026-08-27"},{"id":"iherb_sg","url":"https://sg.iherb.com/c/biotin","label":"iHerb Singapore — category page Vitamin B7 (Biotin), default order, 173 results","quote":"California Gold Nutrition, Biotin, 10,000 mcg, 90 Veggie Softgels … NOW Foods, Biotin, 5,000 mcg, 120 Veg Capsules … NeoCell, Grassfed Collagen Peptides + Vitamin C & Biotin … 21st Century, Biotin, 10,000 mcg, 120 Tablets … Natrol, Biotin, 100 Tablets","accessed":"2026-08-27"}],"brand_certs":null,"updated_at":"2026-08-29T16:16:12.75901+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}