Biotin, also known as vitamin B7 or vitamin H, is a water-soluble vitamin that is essential for the health of the skin, hair, nails, and nervous system. Biotin is found naturally in a variety of foods, including eggs, nuts, whole grains, and leafy green vegetables. Biotin is often used as a dietary supplement to improve the health of the skin, hair, and nails, and it is also used to support the nervous system and maintain healthy metabolism. It is important for the production of keratin, a protein that makes up the structure of the hair, skin, and nails. It metabolises carbohydrates, fats, and proteins, which are important for maintaining energy levels and supporting overall health. Biotin deficiency is rare, but it can occur in individuals who have poor diets or certain medical conditions. Symptoms of biotin deficiency may include hair loss, skin rash, and neurological symptoms such as depression and fatigue.  The caveat is that most people are not truly deficient in biotin, but people have found it to be helpful even without being truly deficient.