Biotin
Biotin is an essential B-vitamin. Supplemental benefit is clearest when correcting deficiency, not for general hair/skin claims.
Overview
What is biotin?
Biotin is an essential B vitamin also known as vitamin B7. It is an essential B vitamin that acts as a cofactor for enzymes involved in metabolizing fats, carbohydrates, and proteins. While commonly used to support hair, skin, and nail health, scientific evidence for these beauty benefits is limited, and its effects on type-2-diabetes require further research.
Dosage
A typical oral dose used in studies is 2.5 mg biotin per day.
Effect graph
Effect heatmap
SupplementDEX Database
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Database Snapshot
Most biotin research is concentrated in a handful of conditions.
- Multiple sclerosis accounts for 9 of 28 studies (32%).
- Type 2 Diabetes accounts for 5 of 28 studies (18%).
- Brittle nails accounts for 4 of 28 studies (14%).
- Sparse coverage remains for Alopecia areata, Biotin deficiency, Muscle cramps.
Dietary Sources
Top dietary sources
Food sources
High amounts of biotin are found in common foods. Foods containing biotin Biotin is found in foods including:
Sources include Apples, Bananas, Cheddar Cheese, Eggs, Milk, Nuts, Oatmeal, Organ Meats, Pork, Salmon, Seeds, Sunflower Seeds, Sweet Potatoes, and Whole Wheat Bread.
Safety
Oral biotin is likely safe at a dose of up to 2.5 mg per day.
The tolerable upper intake level is not known.
Frequently Asked Questions
Takeaway
Biotin is commonly taken for hair growth, but limited evidence suggests that it is effective for this purpose in most healthy people without biotin deficiency.
References
Sources26 references
SupplementDEX uses only high-quality sources to determine supplement effectiveness.
SupplementDEX Database · Biotin deficiency
1 reference1.SupplementDEX Database: Biotin deficiency — Effect of biotin supplementation in infant formula: A multi-center study in Japan2023
In 84 healthy Japanese infants, formula with 2.4 µg/100 kcal biotin raised urinary biotin more than 0.5 µg/100 kcal formula at 1 and 6 months, but ASQ-3 development scores at 9–36 months did not differ.
SupplementDEX Database · Hair growth
4 references2.SupplementDEX Database: Hair growth — Efficacy of 5% topical minoxidil versus 5 mg oral biotin versus topical minoxidil and oral biotin on hair growth in men: randomized, crossover, clinical trial2024
A randomized crossover trial comparing 5% topical minoxidil, 5 mg oral biotin, and combination therapy for hair growth in men was identified, but available abstract text was insufficient to report specific outcomes.
3.SupplementDEX Database: Hair growth — A Randomized, Placebo-controlled Clinical Study Evaluating a Dietary Supplement for Hair Growth2024
In 65 women with thinning hair, 6 months of B-vitamin/zinc/botanical gummies increased hair density by 10.1% and improved self-reported shedding and appearance versus placebo, with no adverse events.
4.SupplementDEX Database: Hair growth — Efficacy of intramuscular injections of biotin and dexpanthenol in the treatment of diffuse hair loss: A randomized, double-blind controlled study comparing two brands2022
In 50 patients with diffuse hair loss, 6 weekly intramuscular biotin plus dexpanthenol injections (Pars or Bayer brands) significantly reduced hair fall and increased hair density; Bayer also improved terminal/vellus hair ratio.
5.SupplementDEX Database: Hair growth — Zinc aspartate, biotin, and clobetasol propionate in the treatment of alopecia areata in childhood1999
A controlled trial of zinc aspartate, biotin, and topical clobetasol for childhood alopecia areata was identified, but available abstract text was insufficient to report specific outcomes.
SupplementDEX Database · Multiple sclerosis
9 references6.SupplementDEX Database: Multiple sclerosis — High-dose biotin for multiple sclerosis: A systematic review and meta-analyses of randomized controlled trials2021
A meta-analysis of 3 RCTs (889 MS patients) found high-dose biotin (≥300 mg/day) for 12–15 months improved 25-foot walk time in progressive MS (RR 2.06) but not composite disability or EDSS; 4.7% had lab test interference.
7.SupplementDEX Database: Multiple sclerosis — Safety and efficacy of MD1003 (high-dose biotin) in patients with progressive multiple sclerosis (SPI2): a randomised, double-blind, placebo-controlled, phase 3 trial2020
In 642 progressive MS patients, MD1003 (100 mg biotin three times daily) for ~20 months did not significantly improve the primary composite disability endpoint (12% vs 9% improved; OR 1.35) versus placebo.
8.SupplementDEX Database: Multiple sclerosis — Relapses During High-Dose Biotin Treatment in Progressive Multiple Sclerosis: a Case-Crossover and Propensity Score-Adjusted Prospective Cohort2020
In 42 progressive MS patients on high-dose biotin, relapses were 7.4-fold more frequent after starting biotin than before (IRR 7.4); propensity-matched cohort analyses also linked biotin to higher relapse risk.
9.SupplementDEX Database: Multiple sclerosis — Relapses in Patients Treated with High-Dose Biotin for Progressive Multiple Sclerosis2020
In 2,628 PMS patients followed ~17 months, high-dose biotin did not significantly increase annualized relapse rate versus matched controls (0.044 vs 0.028; p=0.18) after propensity adjustment.
10.SupplementDEX Database: Multiple sclerosis — High-dose biotin in progressive multiple sclerosis: A prospective study of 178 patients in routine clinical practice2019
In 178 progressive MS patients on high-dose biotin followed 12 months in routine care, 3.8% improved EDSS, 27.6% reported subjective improvement, 2.2% had relapses, and 14% reported adverse events.
11.SupplementDEX Database: Multiple sclerosis — Tardive Reactivation of Progressive Multiple Sclerosis During Treatment with Biotin2019
A case report of primary progressive MS described possible tardive inflammatory reactivation with new T2 brain lesions after 16 months of high-dose biotin (300 mg/day), alongside prior literature on paradoxical biotin effects.
12.SupplementDEX Database: Multiple sclerosis — MD1003 (High-Dose Pharmaceutical-Grade Biotin) for the Treatment of Chronic Visual Loss Related to Optic Neuritis in Multiple Sclerosis: A Randomized, Double-Blind, Placebo-Controlled Study2018
In 93 MS patients with chronic visual loss, 6 months of MD1003 (300 mg/day) did not significantly improve visual acuity versus placebo overall; a nonsignificant trend favored biotin in slowly progressive optic neuropathy subgroup.
13.SupplementDEX Database: Multiple sclerosis — MD1003 (high-dose biotin) for treatment of progressive multiple sclerosis: A randomised, double-blind, placebo-controlled study2016
In 154 progressive MS patients, 12 months of MD1003 (300 mg/day) led to confirmed disability reversal in 12.6% versus 0% on placebo (p=0.005) and reduced EDSS progression versus placebo.
14.SupplementDEX Database: Multiple sclerosis — High doses of biotin in chronic progressive multiple sclerosis: a pilot study2015
An open-label pilot in 23 progressive MS patients found high-dose biotin (100–300 mg/day) for 2–36 months improved visual acuity in 4 patients and spinal cord function in 16 of 18 with prominent spinal involvement.
15.SupplementDEX Database: Seborrheic dermatitis — Oral use of biotin in seborrhoeic dermatitis of infancy: a controlled trial1976
A double-blind crossover trial of oral biotin for infant seborrhoeic dermatitis found no statistically significant advantage of biotin over placebo.
SupplementDEX Database · Brittle nails
4 references16.SupplementDEX Database: Brittle nails — Biotin or Pyridoxine Versus Combined Regimen in the Treatment of Onychoschizia2025
In 61 adults with fingernail onychoschizia, 3 months of combined biotin (1 mg/day) plus pyridoxine (100 mg/day) achieved 69.6% complete response versus 10–11% with either vitamin alone.
17.SupplementDEX Database: Brittle nails — Oral nail growth supplements: a comprehensive review2022
A comprehensive review of oral nail growth supplements noted limited FDA-required efficacy testing for over-the-counter products and summarized mechanisms and side effects of ingredients including biotin.
18.SupplementDEX Database: Brittle nails — Brittle nails: response to daily biotin supplementation1993
In 35 of 44 patients with brittle nails prescribed biotin, 22 (63%) reported clinical improvement and 13 (37%) reported no change in this retrospective case series.
19.SupplementDEX Database: Brittle nails — Treatment of brittle fingernails and onychoschizia with biotin: scanning electron microscopy1990
In 32 subjects, biotin supplementation for several months increased nail thickness by 25% in 8 treated brittle-nail patients, reduced splitting, and improved nail surface regularity on electron microscopy.
SupplementDEX Database · Muscle cramps
1 reference20.SupplementDEX Database: Muscle cramps — Biotin ameliorates muscle cramps of hemodialysis patients: a prospective trial2012
In 14 hemodialysis patients with frequent muscle cramps, 1 mg/day oral biotin promptly reduced cramp severity in 12 of 14 patients during and after dialysis, despite elevated baseline plasma biotin levels.
21.SupplementDEX Database: Polycystic ovary syndrome (PCOS) — Efficacy of combination therapy of inositols, antioxidants and vitamins in obese and non-obese women with polycystic ovary syndrome: an observational study2019
In women with PCOS, 12 weeks of combined myo-inositol, D-chiro-inositol, chromium, NAC, lycopene, vitamin D, biotin, and folic acid improved menstrual cyclicity, acne, hirsutism, and weight in obese but not lean patients.
SupplementDEX Database · Type 2 Diabetes
5 references22.SupplementDEX Database: Type 2 Diabetes — Influence of biotin intervention on glycemic control and lipid profile in patients with type 2 diabetes mellitus: A systematic review and meta-analysis2022
A meta-analysis of 5 RCTs (445 type 2 diabetic patients) found biotin for 28–90 days significantly lowered fasting glucose, total cholesterol, and triglycerides but not insulin; evidence for HbA1c and LDL was insufficient.
23.SupplementDEX Database: Type 2 Diabetes — Chromium picolinate and biotin combination improves glucose metabolism in treated, uncontrolled overweight to obese patients with type 2 diabetes2008
In 447 poorly controlled type 2 diabetic adults, 90 days of chromium picolinate (600 µg) plus biotin (2 mg) lowered HbA1c by 0.54% versus placebo, with greater fasting glucose reductions in those with baseline HbA1c ≥10%.
24.SupplementDEX Database: Type 2 Diabetes — The effect of chromium picolinate and biotin supplementation on glycemic control in poorly controlled patients with type 2 diabetes mellitus: a placebo-controlled, double-blinded, randomized trial2006
In 43 type 2 diabetic patients, 4 weeks of chromium picolinate plus biotin (2 mg/day) reduced 2-h oral glucose tolerance area under the curve and fructosamine versus placebo, without serious adverse events.
25.SupplementDEX Database: Type 2 Diabetes — Biotin supplementation reduces plasma triacylglycerol and VLDL in type 2 diabetic patients and in nondiabetic subjects with hypertriglyceridemia2006
In 33 adults (diabetic and nondiabetic), 28 days of biotin (~61 µmol/day) significantly lowered plasma triglycerides and VLDL versus baseline but did not significantly change glucose, insulin, or cholesterol.
26.SupplementDEX Database: Type 2 Diabetes — Effects of biotin on pyruvate carboxylase, acetyl-CoA carboxylase, propionyl-CoA carboxylase, and markers for glucose and lipid homeostasis in type 2 diabetic patients and nondiabetic subjects2004
In 37 adults, 14–28 days of biotin raised lymphocyte pyruvate carboxylase, propionyl-CoA carboxylase, and acetyl-CoA carboxylase activity but did not change glucose, insulin, lactate, or lipids in diabetic or nondiabetic groups.