Summary
Biotin for hair works best for people who are actually low in biotin, which is uncommon but not rare in women with hair loss.
For healthy people with normal levels, trials show little extra benefit for hair growth. Small studies suggest brittle nails may improve, and high doses can upset some blood tests.
You notice more hair in the brush, or your nails split every time you open a can. Biotin is on almost every hair, skin and nails label. This guide looks at biotin for hair honestly: who it helps, what studies found, how much is enough and the safety issue few people hear about.
| At a glance | Biotin (vitamin B7) |
|---|---|
| What it is | A water soluble B vitamin that helps enzymes turn food into energy |
| Authorised roles (EU) | Maintenance of normal hair, skin and mucous membranes; normal energy metabolism and nervous system |
| Food sources | Eggs, meat, poultry, fish, cheese, nuts, some vegetables and cereals |
| Daily need | EU reference value 50 µg; EFSA adequate intake 40 µg for adults |
| Amounts studied | 2.5 mg a day for brittle nails; 5 to 10 mg in short studies |
| Who benefits most | People with low biotin status or a known risk factor |
What is biotin and why do we need it?
Biotin is a B vitamin that helps five enzymes build fats, break down certain amino acids and make glucose. Fast growing tissues such as hair roots and skin depend on that work.
Biotin contributes to the maintenance of normal hair and normal skin, and to normal energy yielding metabolism. Most people get enough from a mixed diet. For a wider look at how vitamins work together, see our guide to multivitamins for energy and immunity.
Who needs biotin for hair and skin the most?
Dermatology reviews list these risk factors for low biotin:
- People with gut absorption problems, such as inflammatory bowel disease.
- People who eat a lot of raw egg white, which contains avidin, a protein that binds biotin.
- Smokers.
- People on some anticonvulsant medicines or long courses of broad spectrum antibiotics.
- People with biotinidase deficiency, a rare inherited condition managed by doctors.
- Breastfeeding women, whose needs rise slightly to 45 µg a day.
How biotin may help
Thinning hair and hair loss
If hair loss is caused by low biotin, correcting it makes sense. With normal levels, research does not show extra biotin makes hair grow faster or thicker.
Brittle, splitting nails
Here the evidence is most encouraging, though studies are small and old. Zinc and selenium are the nutrients with an authorised EU claim for normal nails; we cover zinc in our article on zinc and recovery.
Skin health
Reviews suggest biotin may help flaky, oily skin linked to low biotin. Vitamin C matters for collagen too; see liposomal vitamin C vs regular vitamin C.
What the research shows on biotin for hair and nails
Brittle nails (1990, Journal of the American Academy of Dermatology). Under an electron microscope, nails of 8 patients with brittle nails became 25% thicker after biotin, with less splitting.
In a Swiss study, 38% of women complaining of hair loss had low biotin levels. That is why testing comes before supplementing.
Women with hair loss (2016, International Journal of Trichology). Biotin deficiency was found in 38% of women who came to a hair clinic with hair loss. Only about 11% had a known risk factor.
Review of reported cases (2017, Skin Appendage Disorders). In all 18 published cases where biotin improved hair or nails, the person had an underlying problem such as deficiency. The authors found no good evidence for healthy people.
Review of controlled studies (2024, Journal of Clinical and Aesthetic Dermatology). Only three studies qualified. The best, a placebo controlled trial, found no difference in hair growth.
Blood test interference (2017, JAMA). Six healthy adults took 10 mg of biotin a day for a week. Results were distorted in 9 of 23 lab tests that use biotin based technology, including thyroid tests.
| Study | Who | What was found |
|---|---|---|
| Colombo, 1990 | Women with brittle nails | Thicker nails, less splitting |
| Trüeb, 2016 | Women with hair loss | 38% had low biotin |
| Patel, 2017 | 18 published cases | Benefit only with an underlying problem |
| Yelich, 2024 | 3 controlled studies | No clear hair benefit in healthy people |
| Li, 2017 | 6 healthy adults, 10 mg daily | Some blood tests gave false results |
How much biotin do you need?
The EU nutrient reference value for labels is 50 µg a day, and EFSA sets an adequate intake of 40 µg for adults, including during pregnancy. No tolerable upper intake level has been set, because no harmful dose has been identified in humans.
- Studied doses: brittle nail studies used 2.5 mg a day, and in one study 91% of 45 people had firmer, harder nails after about five and a half months.
- Timing: biotin can be taken with or without food; judge nail changes over months.
- Raw egg white: large amounts can block biotin; cooked eggs are fine.
Forms of biotin
In food, most biotin is bound to protein and released during digestion. Supplements contain free biotin, which is generally well absorbed. Liposomal delivery matters most for nutrients that dissolve poorly in water, which we explain in which vitamins actually need to be liposomal.
Safety and blood tests
- Biotin is well tolerated, but high levels can make thyroid results look like an overactive thyroid and heart attack markers look falsely low.
- Always tell your doctor or the lab that you take biotin before a blood test. They may ask you to pause it beforehand.
- If you take anticonvulsants, are pregnant or breastfeeding, ask your doctor before supplementing.
- Sudden or patchy hair loss needs a medical check; thyroid, iron and hormones are common causes.
Biotin in FOOON VIT & MIN + CoQ10
VIT & MIN + CoQ10 includes biotin alongside zinc, selenium, copper, iron, vitamin C and a broad range of other vitamins and minerals in slow release liposomal capsules made with sunflower lecithin. That fits the research: hair and nails rely on several nutrients, not one vitamin. The formula is produced in Greece in an ISO certified facility; take up to 2 capsules daily after your main meal, and mention it before any blood test.
Frequently asked questions
Does biotin really help hair growth?
Mainly in people who are low in biotin. With normal levels, controlled studies have not shown faster or thicker hair.
How long does biotin take to work for hair and nails?
Hair and nails grow slowly, so changes take months. In brittle nail studies, people were followed for around five to six months.
How much biotin should I take a day?
The EU reference value is 50 µg a day, and EFSA's adequate intake for adults is 40 µg. Brittle nail studies used 2.5 mg a day, which is best discussed with a doctor.
Can biotin affect blood test results?
Yes. High biotin intake can distort some thyroid, hormone and heart tests, so always tell your doctor or the lab that you take it.
What are the signs of biotin deficiency?
Thinning hair and a scaly red rash around the eyes, nose and mouth are classic signs. A doctor can confirm low levels with a blood test.
Is biotin good for skin?
Biotin contributes to the maintenance of normal skin. Extra biotin is most likely to help when skin problems are linked to low biotin status.
Bottom line
Biotin for hair is not a magic fix, but it matters if you are low. Check for deficiency and other causes of hair loss first, expect slow changes in nails, keep your intake sensible and always mention biotin before blood tests.
Explore VIT & MIN + CoQ10 →Sources
- Colombo VE, Gerber F, Bronhofer M, Floersheim GL. Treatment of brittle fingernails and onychoschizia with biotin: scanning electron microscopy. Journal of the American Academy of Dermatology. 1990. PMID 2273113. doi.org/10.1016/0190-9622(90)70345-i
- Floersheim GL. Treatment of brittle fingernails with biotin. Zeitschrift für Hautkrankheiten. 1989. PMID 2648686. pubmed.ncbi.nlm.nih.gov/2648686
- Trüeb RM. Serum Biotin Levels in Women Complaining of Hair Loss. International Journal of Trichology. 2016. PMID 27601860. doi.org/10.4103/0974-7753.188040
- Patel DP, Swink SM, Castelo-Soccio L. A Review of the Use of Biotin for Hair Loss. Skin Appendage Disorders. 2017. PMID 28879195. doi.org/10.1159/000462981
- Yelich A, Jenkins H, Holt S, Miller R. Biotin for Hair Loss: Teasing Out the Evidence. Journal of Clinical and Aesthetic Dermatology. 2024. PMID 39148962. pubmed.ncbi.nlm.nih.gov/39148962
- Li D, Radulescu A, Shrestha RT, et al. Association of Biotin Ingestion With Performance of Hormone and Nonhormone Assays in Healthy Adults. JAMA. 2017. PMID 28973622. doi.org/10.1001/jama.2017.13705
- Valentim FO, Miola AC, Miot HA, Schmitt JV. 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. Anais Brasileiros de Dermatologia. 2024. PMID 38688776. doi.org/10.1016/j.abd.2023.07.008
- Lipner SR, Scher RK. Biotin for the treatment of nail disease: what is the evidence? Journal of Dermatological Treatment. 2018. PMID 29057689. doi.org/10.1080/09546634.2017.1395799
- Piraccini BM, Berardesca E, Fabbrocini G, Micali G, Tosti A. Biotin: overview of the treatment of diseases of cutaneous appendages and of hyperseborrhea. Giornale Italiano di Dermatologia e Venereologia. 2019. PMID 31638351. doi.org/10.23736/S0392-0488.19.06434-4
- Mock DM. Skin manifestations of biotin deficiency. Seminars in Dermatology. 1991. PMID 1764357. pubmed.ncbi.nlm.nih.gov/1764357
- Dasgupta A. Immunoassay design and biotin interference. Advances in Clinical Chemistry. 2022. PMID 35953126. doi.org/10.1016/bs.acc.2022.03.005
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on Dietary Reference Values for biotin. EFSA Journal. 2014. EFSA Journal 2014
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the substantiation of health claims related to biotin. EFSA Journal. 2009. efsa.europa.eu
- Regulation (EU) No 1169/2011, Annex XIII: nutrient reference values. legislation.gov.uk
- German Federal Institute for Risk Assessment (BfR). Proposed maximum levels for the addition of biotin to foods including food supplements. bfr.bund.de
