Biotin, otherwise known as Vitamin H or B7, is a water-soluble vitamin which plays a vital role in metabolizing fats, proteins and carbohydrates. It assists in the growth of hair, skin, nails, sexual organs, blood cells and bone marrow; and at a more basic level, biotin is necessary for gene replication.
True biotin deficiency is very rare, as B7 is fairly bioavailable in foods, and exists in bacteria which live in the human gut. Nutritional sources of biotin include milk, Brewer's yeast, organ meats, soy and egg yolk. Large quantities of egg white, consumed raw, will bind to biotin and prevent it from being absorbed by the body. Signs of biotin deficiency include lack of growth and progressive hair loss, worsening in severe cases to the loss of eyebrows and eyelashes.
Marginal or functional biotin deficiency occasionally occurs in pregnant women, athletes, people with type 2 diabetes and those with alcoholism. Biotin supplements are readily available from supermarkets and health food stores.
Biotin supplements are generally unnecessary unless used for therapeutic purposes; however, the vitamin is considered non-toxic even in high doses, and no serious toxicity due to high consumption has been recorded. Many countries do not recommend a daily intake of the vitamin, as sufficient quantities are generally obtained through diet; however, the United States' AI (Adequate Intake) is set at 30 micrograms a day, while the RDA (Recommended Daily Intake) for supplementation is 300 micrograms a day. Biotin works most effectively in combination with other B vitamins, particularly B5 (pantothenic acid).
Biotin supplements have been used to treat a range of conditions: