Biotin, also called vitamin B7 or vitamin H is a water-soluble B complex vitamin, which contains an uredo ring fused by a tetrahydrothiophene ring. It is found in several foods, like whole grains, nuts, legumes, unpolished rice and egg yolk. The normal gut flora also produces this vitamin.

Biotin has been used for labeling the swine anti-rabbit IgG antibody and peroxidase.

Biotin also referred to as vitamin H or vitamin B7 is a water-soluble B-vitamin that induces two to three fold increase in guanylate cyclase activity in rat liver, kidney, colon, cerebellum, and heart. It also stimulates the sperm motility and prolongs the survival of cryopreserved human spermatozoa.

Biotin functions as an important cofactor for carboxylase enzymes in several metabolic pathways. It acts as a coenzyme in the metabolism of fatty acids, isoleucine and valine. Biotin is implicated in gluconeogenesis and citric acid cycle. It is involved in keratin synthesis and hence is used as a supplement for skin, hair and nail growth. Biotin promotes cell growth, production of fatty acids and the metabolism of fats and amino acids. It assists the transfer of carbon dioxide and also sustains a steady blood sugar level.