There is no recommended dietary allowance for biotin. Claims of biotin supplements being effective in treating hair loss have not been proven.
Lack of biotin is rare because biotin is readily available in commonly consumed foods, such as bananas, carrots and cereals. Biotin deficiency can, however, be caused by a genetic disorder of biotin deficiency, surgical removal of the stomach, or seborrheic dermatitis in infants. In these cases, hair loss has been observed, leading to the rumor that biotin can grow or regrow hair. While there is no recommended dietary allowance, normal daily recommended biotin intakes range from 30 to 100 micrograms for both adolescents and adults, as stated by the Mayo Clinic.