Biotin
Evidence Fact Sheet
Vitamin B7
Biotin (vitamin B7) is a water-soluble B vitamin and cofactor for the four carboxylase enzymes in metabolism. Typical nutritional intake is 30-100 µg/day, with 2.5-10 mg/day used in hair/skin/nail research. GRAS in the US, EFSA-authorized, with FDA warnings on high-dose immunoassay interference.
Also known as: Vitamin B7 · Vitamin H · D-Biotin · Coenzyme R
Overview
Biotin (vitamin B7, also called vitamin H or coenzyme R) is a water-soluble B vitamin that acts as the cofactor for the four biotin-dependent carboxylases (pyruvate carboxylase, acetyl-CoA carboxylase, propionyl-CoA carboxylase and β-methylcrotonyl-CoA carboxylase) central to gluconeogenesis, fatty-acid synthesis and amino-acid catabolism; it is also studied for keratin-synthesis regulation and histone biotinylation. General nutritional supplementation is typically in the 30-100 µg/day adequate-intake range, while 2.5-10 mg/day is used in hair/skin/nail research contexts; 100-300 mg/day pharmaceutical-grade doses studied in multiple sclerosis are far above the supplement range and are not a supplement reference. Regulatory status: GRAS and a lawful dietary-supplement ingredient in the US (with FDA 2017/2019 safety communications on high-dose streptavidin-biotin immunoassay interference), listed in EFSA Directive 2002/46/EC with seven authorized Reg 432/2012 health claims (hair, skin, mucous membranes, energy and macronutrient metabolism, nervous system, psychological function), and permitted under ANVISA RDC 269/2005 and China GB 14880-2012. It is orally well tolerated, with adverse events rare even at 10 mg/day.
Mechanism of Action
Cofactor for the four biotin-dependent carboxylases (PC, ACC, PCC, MCC) in gluconeogenesis, fatty-acid synthesis and amino-acid catabolism · Pyruvate carboxylase (PC) cofactor — key gluconeogenesis step · Acetyl-CoA carboxylase (ACC) cofactor — rate-limiting step of fatty-acid synthesis · Propionyl-CoA carboxylase (PCC) and β-methylcrotonyl-CoA carboxylase (MCC) cofactors — branched-chain/odd-chain and leucine catabolism · Studied for keratin-synthesis regulation in hair and nail structural proteins · Studied for epigenetic gene-expression regulation via histone biotinylation
Body systems: Hair & Nails · Skin & Connective Tissue · Endocrine & Metabolic · Neurological & Cognitive · METABOLISM
Evidence-Based Benefits
Each benefit below is anchored to a specific PubMed-indexed study. Effect sizes, sample sizes, and p-values are reported as published; no values are inferred. Honest negatives and null results are kept alongside the positive findings, and disease-research populations are described as such — Biotin is not characterized as a treatment for any disease.
High-Dose Biotin in Multiple Sclerosis (Pooled Evidence)
Null / no benefit Meta-analysis supported- 3 RCTs · 889 participantspooled MS trials
- RR 2.87improvement · 95% CI 0.29-28.40
- RR 2.06 (95% CI 1.04-4.09)one secondary outcome · low certainty
A systematic review and meta-analyses pooled three randomized trials of pharmaceutical-grade high-dose biotin in multiple sclerosis. For the main disability-improvement outcome the confidence interval was extremely wide and crossed no effect, so the authors judged the evidence insufficient to show benefit; one secondary outcome reached statistical significance but at only moderate-to-low certainty. This is an honest mixed-to-null result, and it concerns 100-300 mg/day pharmaceutical doses far above any supplement range — not nutritional biotin.
Reported effect: three RCTs involving 889 individuals; improvement RR 2.87 (95% CI 0.29-28.40); a separate outcome RR 2.06 (95% CI 1.04-4.09); insufficient evidence that the HDB and placebo arms differed at 12 to 15 months
“Out of 366 records identified, three RCTs involving 889 individuals diagnosed with MS [...] At 12 to 15 months, there is insufficient evidence that the HDB and placebo arms differed (relative risk (RR) 2.87; 95% CI 0.29-28.40; 2 trials; 796 participants; I2 = 66%) [...] (RR 2.06; 95% CI 1.04-4.09; 2 trials; 796 participants; I2 = 0%) [...] A moderate certainty of evidence suggests a potential benefit in favor of HDB”
Source: PMID 34332461 · Espiritu 2021 · Mult Scler Relat Disord
High-Dose Biotin in Progressive MS (Pivotal Phase 3, SPI2)
Null / no benefit RCT supported- 642 randomized326 biotin · 316 placebo
- 12% vs 9%improved at month 12/15
- OR 1.35 (95% CI 0.81-2.26)primary endpoint · NS
The pivotal SPI2 phase 3 trial randomized 642 patients with progressive multiple sclerosis to high-dose (MD1003) biotin or placebo. The proportion improving on the primary disability endpoint was statistically indistinguishable between arms, and the trial did not meet its primary endpoint. This is the largest single trial and a clear honest negative for the pharmaceutical high-dose indication.
Reported effect: 642 randomized (MD1003 n=326; placebo n=316); 39 (12%) vs 29 (9%) improved at month 12 confirmed at month 15; odds ratio 1.35 (95% CI 0.81-2.26); did not significantly improve disability or walking speed
“39 (12%) of 326 patients in the MD1003 group compared with 29 (9%) of 316 in the placebo group improved at month 12, with confirmation at month 15 (odds ratio 1·35 [95% CI 0·81-2·26]) [...] MD1003 did not significantly improve disability or walking speed in patients with progressive multiple sclerosis.”
Source: PMID 33222767 · Cree 2020 · Lancet Neurol
High-Dose Biotin in Progressive MS (Earlier Positive Trial)
RCT supported- 154 randomizedprogressive MS
- 12.6% vs 0%disability reversal · p=0.005
An earlier, smaller randomized trial of MD1003 high-dose biotin reported that 12.6% of treated patients achieved sustained disability reversal versus none on placebo. This positive signal in a 154-patient study was not reproduced in the larger SPI2 phase 3 trial, illustrating why the pooled meta-analytic verdict is mixed-to-null. Doses studied are pharmaceutical-grade, not nutritional.
Reported effect: 154 patients randomized; 13 (12.6%) MD1003-treated patients achieved the primary endpoint (disability reversal) versus none of the placebo-treated patients (p = 0.005)
“13 (12.6%) MD1003-treated patients achieved the primary endpoint versus none of the placebo-treated patients (p = 0.005) [...] MD1003 achieves sustained reversal of MS-related disability in a subset of patients with progressive MS and is well tolerated.”
Source: PMID 27589059 · Tourbah 2016 · Mult Scler
Marginal Biotin Deficiency in Normal Pregnancy
RCT supported- −11.7 ± 3.6 mmol/mol createarly pregnancy · P<0.006
- −7.1 ± 1.2 mmol/mol creatlate pregnancy · P<0.002
In a biotin-supplementation study during normal pregnancy, the elevated urinary 3-hydroxyisovaleric acid (3-HIA) excretion frequently seen in pregnant women fell significantly after biotin, whereas placebo did not. The authors interpreted this as evidence that marginal biotin deficiency occurs commonly in early pregnancy, supporting biotin's role as an essential nutrient in this population rather than as a treatment.
Reported effect: early-pregnancy group 3-HIA excretion decreased by 11.7 ± 3.6 mmol/mol creatinine (P < 0.006); late-pregnancy group decreased by 7.1 ± 1.2 mmol/mol creatinine (P < 0.002)
“3-HIA excretion decreased (P < 0.006) by 11.7 +/- 3.6 mmol/mol creatinine [...] 3-HIA excretion decreased (P < 0.002) by 7.1 +/- 1.2 mmol/mol creatinine [...] marginal biotin deficiency occurs frequently in the first trimester”
Source: PMID 11815321 · Mock 2002 · Am J Clin Nutr
Sensitive Biomarkers of Marginal Biotin Status (Depletion Model)
RCT supported- 7 adults · 28 degg-white depletion
- P < 0.0001PCC activity ↓ by day 14
- 6 of 7 subjectsabnormal activation coefficient · day 28
Marginal biotin deficiency was experimentally induced in 7 adults by 28 days of raw-egg-white (avidin) feeding. Lymphocyte propionyl-CoA carboxylase (PCC) activity dropped below normal in all subjects within 14 days and its activation coefficient rose abnormally in most by day 28, identifying PCC activity as the most sensitive validated indicator of biotin status. This establishes the biomarker methodology behind biotin-deficiency research rather than a supplementation benefit.
Reported effect: marginal deficiency induced in 7 adults by 28-d egg-white feeding; by day 14 PCC activity decreased (P < 0.0001) below normal in all subjects; by day 28 the activation coefficient was abnormal in 6 of 7 subjects (P = 0.003)
“Marginal biotin deficiency was induced in 7 adults (3 women) by egg-white feeding for 28 d. [...] By day 14, PCC activity had decreased (P < 0.0001) to below the lower limit of normal in all subjects. [...] By day 28, the activation coefficient of PCC had increased significantly (P = 0.003) and was above the upper limit of normal in 6 of 7 subjects.”
Source: PMID 16895887 · Stratton 2006 · Am J Clin Nutr
Chromium Picolinate + Biotin Combination and Glycemic Control
RCT supported- 43 subjectspoorly controlled T2DM
- −9.7% vs +5.1%glucose AUC · P<0.03
A randomized placebo-controlled trial tested a chromium picolinate plus biotin combination (not biotin alone) in 43 patients with poorly controlled type 2 diabetes. The combination produced a significantly greater reduction in the glucose area-under-the-curve during an oral glucose tolerance test versus placebo, alongside fructosamine and triglyceride changes. Because biotin was co-administered with chromium, this trial cannot isolate a biotin-specific effect.
Reported effect: 43 subjects; total area under the curve for glucose during 2-h OGTT changed −9.7% (chromium-biotin) versus +5.1% (placebo), P < 0.03
“significantly greater reduction in the total area under the curve for glucose during the 2-h oral glucose tolerance test [...] mean change -9.7% [...] +5.1%, P < 0.03”
Source: PMID 17109595 · Singer 2006 · Diabetes Technol Ther
Oral Biotin for Hair Growth (Androgenetic Alopecia)
Null / no benefit Emerging / indexed- 5 mg/day oral biotinvs 5% topical minoxidil
Despite biotin's popularity for hair, randomized evidence in people without deficiency is weak. The most recent randomized crossover trial compared 5 mg/day oral biotin against 5% topical minoxidil for male hair growth; the PubMed record carries no abstract, so a verified effect size could not be extracted (RCT exists; effect size not extracted). Biotin's authorized EFSA hair claim reflects its role in maintenance of normal hair as a nutrient, not a demonstrated treatment for hair loss.
Effect size: this study reports the direction of the finding but does not state a specific numeric effect size, so none is given here rather than estimated.
“Efficacy of 5% topical minoxidil versus 5 mg oral biotin versus topical minoxidil and oral biotin on hair growth in men: randomized, crossover, clinical trial”
Source: PMID 38688776 · Valentim 2024 · An Bras Dermatol
Dosage (research context · not a recommendation)
30-100 µg/day adequate-intake (general nutritional supplementation; no IOM upper limit set) · 2.5-10 mg/day used in hair/skin/nail research contexts (clinical trials to 10 mg/day showed no adverse events) · 100-300 mg/day = pharmaceutical-grade MS research dose, far above supplement range and NOT a supplement reference
Regulatory Status · 4 Markets
- US · FDA
- GRAS · lawful dietary-supplement ingredient · structure/function claims (hair/skin/nails/energy metabolism) permissible. FDA 2017/2019 Safety Communications: high-dose biotin interferes with immunoassays (troponin/TSH/BNP) — high-dose products should carry a warning.
- EU · EFSA
- Listed in Directive 2002/46/EC Annex I permitted vitamins. Reg 432/2012 Art.13(1) authorizes 7 biotin health claims: normal energy-yielding metabolism · normal macronutrient metabolism · normal functioning of the nervous system · normal psychological function · maintenance of normal hair · maintenance of normal skin · maintenance of normal mucous membranes. Claims may be used only for food that is at least a SOURCE OF biotin per Reg 1924/2006 (≥15% of the 50 µg NRV per 100 g/ml or per portion).
- CN · China
- Listed as a permitted food nutrition fortifier under GB 14880-2012 and usable in health foods; products may carry the supplement claim 'supplements B-group vitamins', and health-food registrations may apply for related function claims. SAMR recognized.
- BR · ANVISA
- Listed in RDC 269/2005 permitted-vitamins list (biotina). ANVISA functional-claim framework (IN 28/2018) available subject to minimum-quantity thresholds.
Authorized Claims
EFSA — “Biotin contributes to the maintenance of normal hair” (Reg (EU) 432/2012 Annex (Art. 13(1)))
EFSA — “Biotin contributes to normal energy-yielding metabolism” (Reg 432/2012)
EFSA — “Biotin contributes to normal macronutrient metabolism” (Reg 432/2012)
EFSA — “Biotin contributes to the normal functioning of the nervous system” (Reg 432/2012)
EFSA — “Biotin contributes to normal psychological function” (Reg 432/2012)
EFSA — “Biotin contributes to the maintenance of normal hair” (Reg 432/2012)
EFSA — “Biotin contributes to the maintenance of normal skin” (Reg 432/2012)
EFSA — “Biotin contributes to the maintenance of normal mucous membranes” (Reg 432/2012)
Safety
Orally very well tolerated; adverse events rare even at 10 mg/day. CRITICAL ASSAY INTERFERENCE: intake ≥1 mg/day can interfere with streptavidin-biotin immunoassays (troponin, TSH, BNP and others), producing falsely high or low results — FDA issued 2017/2019 safety communications and at least one death has been linked to biotin-confounded troponin testing. Patients on high-dose biotin should inform their clinician and consider stopping ≥72 h before laboratory testing. Marginal deficiency may occur in pregnancy; supplementation in pregnancy is a matter for medical supervision. Long-term high-dose safety data are limited.
Related
Goals: hair-nail · skin-beauty
Lifestyles: senior-60-plus
References
PubMed-indexed citations anchoring the benefit findings above. Effect sizes are reported as published.
- PMID 34332461 · Espiritu 2021 · Mult Scler Relat Disord — High-Dose Biotin in Multiple Sclerosis (Pooled Evidence)
- PMID 33222767 · Cree 2020 · Lancet Neurol — High-Dose Biotin in Progressive MS (Pivotal Phase 3, SPI2)
- PMID 27589059 · Tourbah 2016 · Mult Scler — High-Dose Biotin in Progressive MS (Earlier Positive Trial)
- PMID 11815321 · Mock 2002 · Am J Clin Nutr — Marginal Biotin Deficiency in Normal Pregnancy
- PMID 16895887 · Stratton 2006 · Am J Clin Nutr — Sensitive Biomarkers of Marginal Biotin Status (Depletion Model)
- PMID 17109595 · Singer 2006 · Diabetes Technol Ther — Chromium Picolinate + Biotin Combination and Glycemic Control
- PMID 38688776 · Valentim 2024 · An Bras Dermatol — Oral Biotin for Hair Growth (Androgenetic Alopecia)
Frequently Asked Questions
1. Does high-dose biotin work for multiple sclerosis?
The pooled randomized evidence is mixed-to-null. A meta-analysis of three RCTs (889 participants) found insufficient evidence of benefit on the main disability outcome (improvement RR 2.87, 95% CI 0.29-28.40), and the pivotal phase 3 SPI2 trial (642 patients) did not meet its primary endpoint (12% vs 9% improved, OR 1.35, 95% CI 0.81-2.26). An earlier smaller trial was positive (12.6% vs 0%, p=0.005) but was not reproduced. Importantly, these trials used pharmaceutical-grade doses (roughly 100-300 mg/day) far above any nutritional supplement range.
2. Will biotin supplements make my hair grow?
For people who are not biotin-deficient, the randomized evidence is weak and a verified effect size could not be extracted from the most recent trial (5 mg/day oral biotin vs 5% topical minoxidil; abstract not available). EFSA authorizes the claim that biotin contributes to the maintenance of normal hair, which reflects its role as an essential nutrient rather than a proven treatment for hair loss. This page reports research findings and does not provide dosing or treatment advice.
3. Why does biotin status matter in pregnancy?
Biomarker research suggests marginal biotin deficiency is common in normal pregnancy. In a supplementation study (26 pregnant women), elevated urinary 3-hydroxyisovaleric acid fell significantly after biotin (early pregnancy −11.7 ± 3.6, P<0.006; late pregnancy −7.1 ± 1.2 mmol/mol creatinine, P<0.002), interpreted as reduced biotin status. This is a research finding about nutrient status; supplementation in pregnancy is a matter for medical supervision, not something this evidence page advises on.
4. Is biotin safe, and are there any cautions?
Oral biotin is very well tolerated, with adverse events rare even at 10 mg/day. The main documented caution is laboratory, not toxicity: high-dose biotin can interfere with streptavidin-biotin immunoassays (such as troponin, TSH and BNP), producing falsely high or low results — the FDA issued 2017 and 2019 safety communications on this. The chromium-biotin diabetes data (glucose AUC −9.7% vs +5.1%, P<0.03) come from a combination product and cannot isolate a biotin-specific effect.
Last evidence review: 2026-06-13