Biotin is one of the few oral therapies that has shown promise in the scientific literature for the treatment of brittle nails (weak, peeling nails). Biotin is a B-complex vitamin and because it is water soluble, it is safe because your body will eliminate whatever excess it does not need. The recommended dose for brittle nails is 2.5 mg. daily. Because it takes an average of six months for a fingernail to replace itself, you should be committed to taking biotin for four to six months. Biotin can be found at your local health food store.
— Dana Stern, M.D. is a board-certified dermatologist specializing in nails. She works in private practice in New York City.