Biotin is a member of the B-complex group of water-soluble vitamins. Water-soluble vitamins are stored in the body in very limited amounts and are excreted through the urine. Biotin can be found in two natural forms—the free vitamin form and biocytin, which is composed of biotin attached to the amino acid lysine. Biocytin is an inactive form of the vitamin. The lysine must be removed before it can be used by the body.
Biotin is present naturally in a wide variety of foods. It is also made by the bacteria that normally live in our intestines.
Biotin's main function is to help your body's cells produce energy. It does this by working with four essential enzymes that break down fat, carbohydrate, and protein to yield energy. Biotin also plays a role in the synthesis and function of DNA.
A biotin deficiency is rare in healthy people who eat a healthful diet, since we usually get enough from the bacteria living in our digestive tracts.
However, certain conditions and life stages can increase the risk of a deficiency. For example, an enzyme called biotinidase is essential to convert biocytin into biotin. Though both biocytin and biotin are easily absorbed in the small intestines, the body can only use the biotin form. If biotinidase is lacking or not working properly, a biotin deficiency can result.
Some people who may be at risk for a biotin deficiency include the following:
Clinical symptoms of a biotin deficiency include:
There have been no reports of adverse effects due to eating too much biotin. Maximum dosages have not been established.
Major Food Sources
Biotin can be found in a wide variety of foods including eggs, liver, yeast breads, whole grains, sardines, legumes, and mushrooms.
This table lists common foods and their biotin contents.
There is some highly preliminary evidence suggesting supplemental biotin can help to reduce blood sugar levels in people with diabetes. Biotin may also reduce the symptoms of diabetic neuropathy, though other supplements have much stronger evidence. Even weaker evidence suggests that biotin supplements can promote healthy nails and eliminate cradle cap, a scaly head rash often found in infants.
Tips for Increasing Your Biotin Intake
To increase your intake of biotin, try the following:
Academy of Nutrition and Dietetics
United States Department of Agriculture
Dietitians of Canada
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Biotinidase deficiency. Illinois Department of Public Health website. Available at: http://www.idph.state.il.us/HealthWellness/fs/biotinidase.htm. Accessed April 8, 2013.
Coretta C, Bowers E, Cox T, et al. Biotin. North Carolina State University website. Available at: http://www4.ncsu.edu/~knopp/BCH451/Biotin.htm. Accessed April 8, 2013.
Mock DM. Biotin. In: Rucker B, Suttie J, McCormick D, Machlin L, eds. Handbook of Vitamins. New York, NY: Marcel Dekker; 2001:397-426.
Sealey WM, Teague AM, Stratton SL, et al. Smoking accelerates biotin catabolism in women. Am J Clin Nutr. 2004;4:932-935.
Last reviewed April 2013 by Brian Randall, MD