Biotin, also known as Vitamin B7 or H, is a B vitamin that helps improve and maintain healthy looking hair, skin, and nails. Biotin plays a major role in the natural hair manufacturing process. This vitamin is essential to not only grow new hair, but crucial in improving the overall health of your hair. Biotin also boosts the metabolism, helps maintain healthy muscle tissue, as well as heart and blood sugar function. Since the body does not absorb biotin when it is applied to the skin, many individuals prefer biotin injections.