At the top of the list is biotin, sometimes called vitamin B7 or H. Biotin is a water-solubleB-vitamin that is necessary for healthy hair, skin, and nail growth. People who become deficient in this one essential vitamin tend to have thinning hair and poor skin. Physicians often prescribe vitamin B7 supplements when they have a patient with a hair disorder or brittle nails.
The most common theory behind biotin’s effectiveness involves the cortex of the hair. A healthy strand of hair is elastic because it has a strong, flexible cortex. Without that elasticity, hair tends to break and split at the ends.
This is one reason that many companies producing hair supplements list biotin as their only ingredient. A more diverse formula, however, is the better option for maximum effectiveness.