Biotin, also known as vitamin B7, helps breakdown fat, protein, and carbohydrates in the body. Biotin plays an essential role as an enzyme to help during metabolism to make food into fuel. Biotin is found naturally in foods like eggs, milk, and even bananas. Not enough biotin in your diet can lead to brittle nails and can impact hair and skin. A biotin supplement can help you meet your daily biotin needs and support healthy skin, hair, and nails.