Biotin

AEMPS

Vitamin B7 (H). Water-soluble vitamin, cofactor of four carboxylases. AEMPS registers biotin as a medicine for treating confirmed deficiency; in multivitamins and mono-supplements – dietary supplement

ATC code: A11HA05 (Biotin (vitamin B7, H))

Brand names – supplements

Sports Research Biotin 5000 mcg, Pure Encapsulations Biotin 8 mg, Nature's Bounty Biotin 10 000 mcg, Jarrow Formulas Biotin 5000 mcg

Supplements are not tested in clinical trials and are not registered as medications.

Mechanism of action

Biotin is a water-soluble B vitamin. It works as a prosthetic group in four mitochondrial carboxylases: pyruvate carboxylase (gluconeogenesis), acetyl-CoA carboxylase (fatty acid synthesis), propionyl-CoA carboxylase (branched-chain amino acid catabolism) and 3-methylcrotonyl-CoA carboxylase (leucine catabolism). Adequate intake is 30 mcg/day for adults ( AI, NIH ODS), achieved by a normal diet (liver, egg yolk, nuts, whole grains); gut microbiota partially synthesises biotin. True deficiency is rare: prolonged raw egg white intake (avidin binds biotin), chronic malabsorption, congenital biotinidase defects, prolonged anticonvulsant use (phenytoin, carbamazepine, valproate). EFSA Reg 432/2012 approved the claim «contributes to normal hair and skin» at adequate intake – this is a maintenance-of-normal-state claim, not a treatment claim for hair loss or skin aging. Biotin in immunoassays interferes with biotin-streptavidin-based tests (troponin, TSH, T4, hCG, PTH) – Safety Communication 2017/2019.

Indications

Biotin deficiency

First line

Confirmed biotin deficiency is the only evidence-based indication. True deficiency is rare and presents with periorificial dermatitis, hair loss, conjunctivitis and neurological symptoms (ataxia, depression). Possible causes: prolonged biotin-free parenteral nutrition, chronic malabsorption, congenital biotinidase deficiency (newborns, diagnosed via neonatal screening), prolonged anticonvulsant use. AEMPS registered Medebiotin 5 mg for treatment of confirmed deficiency. Laboratory confirmation is advisable before prescribing: urinary 3-hydroxyisovaleric acid or serum biotin. Dose for adult deficiency is 1-10 mg/day orally; in newborns with biotinidase deficiency – 5-10 mg/day lifelong.

Sources

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Chronic fatigue

Not recommended

Biotin (vitamin B7) is a water-soluble vitamin marketed as a supplement for energy and against fatigue. There is no convincing evidence that biotin helps with chronic fatigue – the data for this use are lacking, and biotin deficiency is very rare in people on a normal diet. For persistent fatigue it makes more sense to look for the cause with a doctor: check sleep, thyroid function, iron and B12 levels, and emotional state.

Sources

Skin, hair and nails (supplement marketing)

Not recommended

Biotin is widely sold «for hair growth and nail beauty». approved the claim «contributes to normal hair and skin» at adequate intake – this is a MAINTENANCE-of-normal-state claim, not a TREATMENT claim for hair loss in non-deficient individuals. Patel 2017 systematic review (18 cases) showed clinical improvement in hair loss ONLY in patients with confirmed biotin deficiency or rare congenital syndromes. In healthy adults without deficiency, RCTs with clinical endpoints for biotin 1-10 mg/day did not show meaningful effect on hair or nails. 2022 does not include biotin in hair loss recommendations. Doses in commercial supplements reach 5000-10000 mcg (100-300 times the adequate intake of 30 mcg/day) – such doses do not benefit healthy individuals but create a serious analytical risk (see below). Hair loss workup matters: ferritin, TSH, scalp examination, ruling out androgenetic alopecia. If biotin was recommended without blood work and examination, consider seeking a second opinion from a dermatologist.

Sources

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Official sources

Direct links to regulator labels. Open in a new tab.

AEMPS / CIMA

Spanish Medicines Information Centre (CIMA)

Label dated: 10/24/2024

FDA / DailyMed

FDA — DailyMed Drug Labels

Label dated: 03/07/2026

Safety

Contraindications

Established hypersensitivity to product components
Intake within 8 hours of troponin, TSH, T4, T3, hCG, PTH, cortisol, ferritin testing (risk of falsely low or falsely high results; discontinue 48-72 hours before testing at doses ≥5 mg/day)

Serious adverse effects

Interference with biotin-streptavidin immunoassays: falsely low troponin (risk of missed myocardial infarction), falsely low TSH with falsely high T4 (mimicking hyperthyroidism), falsely high hCG (FDA Safety Communication 2017/2019). Cardiology cases: in acute coronary syndrome in a patient taking biotin 10 mg/day, troponin was falsely low – diagnostic delay and death in one reported case
False hyperthyroid pattern on labs in euthyroid patient – erroneous thyrostatic prescription

Common adverse effects

Skin rash with individual intolerance (rare)
Mild dyspepsia at high doses

PregnancyFDA N

Biotin at adequate intake (30-35 mcg/day, including prenatal multivitamins) is safe. AEMPS Medebiotin 5 mg permits use in pregnancy with clear clinical need (confirmed deficiency). High doses of 5-10 mg/day in non-deficient pregnant women are not studied and not recommended. Before blood tests (including TSH, hCG screening) inform the laboratory about biotin intake.

Breastfeeding

Compatible with breastfeeding. Biotin is naturally present in breast milk.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Biotin used for?

Biotin is evaluated for the following indications with varying evidence strength: Biotin deficiency (evidence tier A), Skin, hair and nails (supplement marketing) (evidence tier D), Chronic fatigue (evidence tier D). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Biotin?

Common side effects of Biotin (≥ 1 in 100): Skin rash with individual intolerance (rare), Mild dyspepsia at high doses. See the Safety section for uncommon and serious reactions.

Is Biotin safe during pregnancy?

FDA category N. Biotin at adequate intake (30-35 mcg/day, including prenatal multivitamins) is safe. AEMPS Medebiotin 5 mg permits use in pregnancy with clear clinical need (confirmed deficiency). High doses of 5-10 mg/day in non-deficient pregnant women are not studied and not recommended. Before blood tests (including TSH, hCG screening) inform the laboratory about biotin intake.

Is Biotin compatible with breastfeeding?

Compatible with breastfeeding. Biotin is naturally present in breast milk.

Who should not take Biotin?

Biotin is contraindicated in: Established hypersensitivity to product components; Intake within 8 hours of troponin, TSH, T4, T3, hCG, PTH, cortisol, ferritin testing (risk of falsely low or falsely high results; discontinue 48-72 hours before testing at doses ≥5 mg/day). Full list in the Safety section.

Mechanism of action

Indications

Biotin deficiency

First line

Sources

Safety

Contraindications

Established hypersensitivity to product components
Intake within 8 hours of troponin, TSH, T4, T3, hCG, PTH, cortisol, ferritin testing (risk of falsely low or falsely high results; discontinue 48-72 hours before testing at doses ≥5 mg/day)

Serious adverse effects

Interference with biotin-streptavidin immunoassays: falsely low troponin (risk of missed myocardial infarction), falsely low TSH with falsely high T4 (mimicking hyperthyroidism), falsely high hCG (FDA Safety Communication 2017/2019). Cardiology cases: in acute coronary syndrome in a patient taking biotin 10 mg/day, troponin was falsely low – diagnostic delay and death in one reported case
False hyperthyroid pattern on labs in euthyroid patient – erroneous thyrostatic prescription

Common adverse effects

Skin rash with individual intolerance (rare)
Mild dyspepsia at high doses

PregnancyFDA N

Breastfeeding

Compatible with breastfeeding. Biotin is naturally present in breast milk.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Biotin used for?

What are the side effects of Biotin?

Common side effects of Biotin (≥ 1 in 100): Skin rash with individual intolerance (rare), Mild dyspepsia at high doses. See the Safety section for uncommon and serious reactions.

Is Biotin safe during pregnancy?

Is Biotin compatible with breastfeeding?

Compatible with breastfeeding. Biotin is naturally present in breast milk.

Who should not take Biotin?