Biotin
Also called Vitamin B7 / Vitamin H
Biotin is the standard supplemental form of vitamin B7. It is well absorbed and very safe at the RDA of 30 mcg. Higher doses (2,500–5,000 mcg) are commonly used for brittle nails and hair loss, but benefits are most pronounced when deficiency is present. High-dose biotin can interfere with lab tests, so it should be paused before blood work.
Best for
Brittle nails and hair support when deficient
Absorption
High
Tolerability
Excellent at standard doses; high doses may cause acne
Typical timing
Morning with food; stop 48–72 hours before blood tests
How to take Biotin
A typical dose of Vitamin B7 (Biotin): 30 mcg RDA; 2,500–5,000 mcg for nails/hair (temporary use). Best timing: Morning with food; stop 48–72 hours before blood tests. The form you choose mainly affects absorption and how easily it sits with your stomach, not the overall dose.