Biotin is a water-soluble B vitamin, also called vitamin B7 and formerly known as vitamin H or coenzyme R. It is involved in a wide range of metabolic processes, both in humans and in other organisms, primarily related to the utilization of fats, carbohydrates, and amino acids. Biotin helps your body convert food into energy. It is especially important during pregnancy and breastfeeding. In addition, biotin is important for the health of your hair, skin, and nails. A lack of biotin is rare. However, if it occurs it may lead to skin rash, loss of hair, high blood levels of cholesterol, and heart problems.