Biotin (vitamin B7) helps your body turn food into energy. It is popular in hair and nail supplements, but the NIH warns that high doses can give false results in some lab tests.
Here are the facts on daily needs, food sources and safety.
Daily biotin requirement
Average daily recommended amount (mcg):
- Children 1 to 3 years: 8 mcg
- Children 4 to 8 years: 12 mcg
- Children 9 to 13 years: 20 mcg
- Teens 14 to 18 years: 25 mcg
- Adults: 30 mcg
- Pregnant women: 30 mcg, breastfeeding women: 35 mcg
No upper limit is stated, and the NIH says biotin has not been shown to cause harm.
Best food sources of biotin
Good sources include:
- Meat, fish, eggs and organ meats such as liver
- Seeds and nuts
- Sweet potatoes, spinach and broccoli
Biotin deficiency
Deficiency is very rare in the US. Signs include thinning hair, loss of body hair, rash around the eyes, nose and mouth, brittle nails, skin infection and, in severe cases, seizures. In infants it can cause weak muscle tone and delayed development.
Higher risk: people with biotinidase deficiency (a rare genetic disorder), people with alcohol dependence, and pregnant or breastfeeding women. At least a year of antiseizure medicine can also lower biotin levels.
Biotin supplements and lab tests
Supplements with more biotin than the recommended amount can cause false results in some lab tests, including thyroid hormone tests. If you take biotin for hair or nails, tell your doctor before any blood test. Biotin is sold in multivitamins, B-complex and biotin-only products.
Frequently Asked Questions
How much biotin do adults need per day?
Adults need 30 mcg per day. Breastfeeding women need 35 mcg.
Can biotin affect blood test results?
Yes. High-dose biotin can give false results in some lab tests, including thyroid hormone tests, so tell your doctor you take it.
Which foods are rich in biotin?
Eggs, meat, fish, organ meats, seeds, nuts, sweet potatoes, spinach and broccoli.
Is biotin deficiency common?
No. It is very rare in the US, mostly seen in biotinidase deficiency, alcohol dependence or long antiseizure medicine use.
Does biotin make hair grow?
The NIH lists hair thinning as a sign of deficiency, but this guide does not claim supplements help people who are not deficient.
Related reading: Vitamin B12 deficiency symptoms | Vitamin B5 (pantothenic acid) daily needs | Vitamin B6 daily needs
Sources
Medical disclaimer: this article is for general information and does not replace advice from a qualified doctor. Do not start, stop or change any supplement or medicine without medical advice.
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