Biotin

Studies in people

• No harm found

  Hair loss in women²

  In women with hair loss, biotin levels in blood and urine were no different from women without it.

• No harm found

  Hair loss after weight-loss surgery³

  In people who had weight-loss surgery, taking biotin made little difference to hair loss.

Animal and lab studies only

• Open question

  Allergy and lab test results⁶

  In lab studies, biotin can interfere with allergy blood tests, causing false positive or false negative results.

Study type not stated

• Open question

  Skin, hair and nail health⁴

  Scientists do not yet know whether biotin supplements help skin, hair or nails, because too few large studies exist.

How it’s made and used

• Vitamin needs in the diet⁵

  Biotin is a vitamin the body cannot make, so people get it from gut bacteria or food.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least two findings in people. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.