Vitamin
Vitamin B7
Vitamin B7 (biotin) helps the body make energy from food. It is found in many foods and also made by gut bacteria, so deficiency is very rare.
What it is
Biotin is a water-soluble B vitamin, sometimes marketed for hair and nails, that is needed only in tiny amounts.
What it does
It helps the body break down fats, carbohydrates and protein to release energy.
Good sources
Found in a wide variety of foods in small amounts, including eggs, liver, some nuts and seeds, and some vegetables; gut bacteria also make some.
Deficiency and who is at risk
Deficiency is very rare and usually linked to specific circumstances, such as certain rare inherited conditions or eating large amounts of raw egg white over a long time. It can cause hair thinning and skin rashes.
Balance
Can you have too much?
Biotin from food and supplements is not known to be harmful, but high-dose supplements can interfere with some blood test results, so tell your doctor if you take them.
Education and reference only. This is general nutrition information, not personal advice, and does not give doses. Ask a pharmacist, GP or registered dietitian before starting supplements, especially with a health condition or in pregnancy.
Answers
Vitamin B7: frequently asked questions
Does biotin improve hair and nails?
Biotin is often marketed for hair and nails, but there is little evidence that supplements help people who are not deficient — and deficiency is very rare. A balanced diet provides what most people need.
Can biotin affect blood tests?
Yes. High-dose biotin supplements can interfere with certain blood tests, including some thyroid and heart tests, so tell your doctor or the laboratory if you take them.
Related
More on vitamins and nutrition
Sources
Where this is drawn from
- NHS — Vitamins and minerals
- British Dietetic Association (BDA)
- UK Scientific Advisory Committee on Nutrition (SACN)
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