Vitamin B7 is also known as biotin, which is necessary for energy production, cell growth, production of fatty acids, and the metabolism of fats and amino acids. It plays a primary role in all of our cells’ energy production by being an integral player in the citric acid cycle where biochemical energy is generated as we breathe. Biotin is often recommended for strengthening hair and nails and is therefore found in related products. Little evidence exists that it can deliver on this recommendation unless someone was deficient, which would is rare in developed nations. Full biotin deficiency is rare because in healthy persons our intestinal bacteria produce it in excess of the body's daily requirements, which are only about 30-100mcgs/day. That said, there are individuals with abnormal metabolism of biotin leading to certain metabolic disorders. In this case they may be treated by a qualified physician with biotin therapy. Generally biotin supplementation can correct the related deficiencies. Also diabetics have been treated with supplementation to help improve blood sugar control. Biotin can also play a role in preventing diabetes-related neuropathy, decreasing the numbness and tingling associated with poor glucose control. Since signs and symptoms of biotin deficiency include hair loss including eventual loss of eyelashes/eyebrows and easily breaking nails, biotin supplements are often suggested at a dose of ~5000-7500mcg/day. If to be effective the correction may take months of regular supplement use. If you have symptoms of biotin deficiencies (dermatitis, hair loss, or neuromuscular dysfunction) you should see your doctor for treatment. If you are marginally deficient as some populations can be, such as athletes maintaining low body fat, active dieters, and pregnancy, a daily multivitamin and mineral formula (MVM) containing 100-300mcgs (higher end for active people) of biotin can adequately fill the gap.