Biotin (vitamin B7) is present in foods such as eggs, milk, and bananas. A lack of biotin can result in hair loss and a rash on the face. Biotin is prescribed to treat biotin deficiency. It is also often used to treat hair loss, brittle nails, and other problems. If you are using biotin supplements and require blood testing, consult your doctor. Biotin is probably safe for most individuals when used at amounts of up to 300 mg daily for up to 6 months. However, it is more typically taken in smaller dosages of 2.5 mg daily. If you are allergic to biotin, do not use this product. If you are pregnant or breast – feeding, consult your doctor before using biotin. Your dosage requirements may alter during pregnancy or while breastfeeding.