Vitamin B7 (biotin) is a water-soluble vitamin that helps maintain normal hair, normal skin, and normal mucous membranes. Biotin also plays an important role in the normal functioning of the nervous system and contributes to normal psychological function. It is a popular vitamin in hair supplements.

Additionally, biotin participates in the body's energy metabolism by contributing to the metabolism of carbohydrates, fats, and proteins. The vitamin is important for cellular energy production and is involved in several processes where the body converts nutrients into energy.