Natural Factors Biotin - 1000 mcg - Promotes strong, healthy nails, hair, and skin. Biotin is a B-complex vitamin (B7) that is vital for the metabolism of carbohydrates, fats, and proteins, helping to convert food into energy. It also supports healthy blood sugar regulation. Biotin has been shown to improve the appearance of nails by increasing nail thickness by approximately 25% and reducing brittleness and nail splitting. Biotin also encourages the growth of strong, thick, healthy-looking hair and can help reverse the loss of hair and hair colour that may result from a biotin deficiency.