Biotin is a B vitamin that plays an essential role in many metabolic reactions ranging from oxidation of fatty acids and carbohydrates to glucose metabolism. Biotin can be useful for preventing and/or treating thinning hair, brittle nails, and even diabetes. Those who are pregnant and those rapidly losing weight are at greater risk for deficiency. Dr. Sue's Biotin tablets not only contain Biotin, but also contain vitamin C and calcium for optimal absorption.