Vitamins
Biotin (vitamin B7)
Also called: biotin, vitamin H, vitamin B7
A B vitamin needed to use fats and proteins.
- Why people take it
- Hair, skin and nails.
- What the evidence says
- Only helps hair or nails in the rare people who lack it.
- How it is usually taken
- Usually 30 mcg to 5 mg a day; many hair products contain 5,000 to 10,000 mcg. Found in eggs, nuts and seeds.
- Be careful
- High doses interfere with many blood tests, including heart (troponin) and thyroid tests, giving false results. Tell the lab you take it.
- Medicines it can interact with
- High doses give falsely high or low results in thyroid, troponin (heart attack) and hormone blood tests; stop 2 to 3 days before tests.
Other vitamins
Common questions
What is Biotin?
A B vitamin needed to use fats and proteins.
Why do people take Biotin?
Hair, skin and nails.
Does Biotin work?
Only helps hair or nails in the rare people who lack it.
How much Biotin do people take?
Usually 30 mcg to 5 mg a day; many hair products contain 5,000 to 10,000 mcg. Found in eggs, nuts and seeds.
Is Biotin safe?
High doses interfere with many blood tests, including heart (troponin) and thyroid tests, giving false results. Tell the lab you take it.
Does Biotin interact with medicines?
High doses give falsely high or low results in thyroid, troponin (heart attack) and hormone blood tests; stop 2 to 3 days before tests.
Sources and further reading
Last reviewed 31 October 2026. Written by Satya Babu.
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