Biotin also called vitamin H (the H represents Haar und Haut, German words for “hair and skin”), vitamin B7 or vitamin B8 (in many countries like France, where vitamin B7 is used for Inositol) is a water-soluble B vitamin. It is involved in a wide range of metabolic processes, both in humans and in other organisms, primarily related to the utilization of fats, carbohydrates, and amino acids.
Biotin deficiency can be caused by inadequate dietary intake or inheritance of one or more inborn genetic disorders that affect biotin metabolism. Subclinical deficiency can cause mild symptoms, such as hair thinning, brittle fingernails, or skin rash, typically on the face. Neonatal screening for biotinidase deficiency started in the United States in 1984, with many countries testing for this disorder at birth. Individuals born prior to 1984 are unlikely to have been screened, obscuring the true prevalence of the disorder.