Biotin, a water-soluble B vitamin, acts as a coenzyme in the metabolism of protein, fats, and carbohydrates.
Where is it found?
Good dietary sources of biotin include organ
meats, oatmeal, egg yolk,
soy, mushrooms, bananas,
peanuts, and brewer’s yeast.
Bacteria in the intestine also produce significant amounts of biotin, but evidence is
conflicting as to whether biotin produced by intestinal bacteria is present at a location or
is in a form that permits significant absorption by the body.1
Biotin has been used in
connection with the following conditions (refer to the individual
health concern for complete information):
Who is likely to be deficient?
Certain rare inborn diseases can leave people with depletion of biotin due to the inability
to metabolize the vitamin normally. A dietary deficiency of biotin, however, is quite
uncommon, even in those consuming a diet low in this B vitamin. Nonetheless, if someone eats
large quantities of raw egg whites, a biotin
deficiency can develop, because a protein in the raw egg white inhibits the absorption of
biotin. Cooked eggs do not present this problem. Long-term antibiotic use can interfere with biotin production in
the intestine and increase the risk of deficiency symptoms, such as dermatitis, depression, hair loss,2 anemia, and nausea. Long-term use of anti-seizure
medications may also lead to biotin deficiency.3 Alcoholics, people with inflammatory bowel disease, and those with diseases of
the stomach have been reported to show evidence of poor biotin status. However, the usefulness
of biotin supplementation for these people remains unclear.4 In animals, and
possibly in humans, biotin deficiency can cause
birth defects.5 As biotin deficiency may occur in as many as 50% of pregnant
women,6 it seems reasonable to use a prenatal multiple vitamin and mineral formula
that contains biotin.
How much is usually taken?
The ideal intake of biotin is unknown. However, the amount of biotin found in most diets,
combined with intestinal production, appears to be adequate for preventing deficiency
symptoms. Researchers have estimated that 30 mcg per day appears to be an adequate intake for
adults.7 Typically, consumption from a Western diet has been estimated to be
30–70 mcg per day. Larger amounts of biotin (8–16 mg per day) may be supportive
for people with diabetes by lowering blood
glucose levels and by preventing diabetic neuropathy.8 9 Biotin in the
amount of 2.5 mg per day strengthened the fingernails of two-thirds of a group of people with
brittle nails, according to one clinical
Are there any side effects or interactions?
Excess intake of biotin is excreted in the urine; no toxicity symptoms have been
Biotin works with some other B vitamins, such as folic acid, pantothenic acid (vitamin B5), and vitamin B12. However, no solid evidence indicates that
people supplementing with biotin also need to take these other vitamins. Symptoms of
pantothenic acid or zinc deficiency have been
reported to be lessened with biotin,11 though people with these deficiencies should
supplement with the nutrients in which they are deficient. Researchers have speculated that
biotin and alpha lipoic acid may compete with
each other for absorption or uptake into cells; but little is known about the importance of
these interactions in humans.12
There is one report of a 76-year-old woman who developed a life-threatening condition
(eosinophilic pleuropericardial effusion) while taking 10 mg of biotin per day and 300 mg of
pantothenic acid per day.13 However, it is not clear whether the vitamins caused
Are there any drug
Certain medicines may interact with biotin. Refer to drug interactions for a list of those medicines.
1. Mock DM. Biotin. In: Shils ME, Olson JA, Shike M, Ross, AC (eds).
Modern Nutrition in Health and Disease. Baltimore: Williams and Wilkins, 1999,
2. Mock DM. Skin manifestations of biotin deficiency. Semin
3. Said HM, Redha R, Nylander W. Biotin transport in the human intestine:
inhibition by anticonvulsant drugs. Am J Clin Nutr 1989;49:127–31.
4. Zempleni J, Mock DM. Biotin biochemistry and human requirements. J
Nutr Biochem 1999;10:128–38 [review].
5. Zempleni J, Mock DM. Marginal biotin deficiency is teratogenic.
Proc Soc Exp Biol Med 2000;223:14–21 [review].
6. Mock DM, Quirk JG, Mock NI. Marginal biotin deficiency during normal
pregnancy. Am J Clin Nutr 2002;75:295–9.
7. Zempleni J, Mock DM. Biotin biochemistry and human requirements. J
Nutr Biochem 1999;10:128–38 [review].
8. Coggeshall JC, Heggers JP, Robson MC, Baker H. Biotin status and
plasma glucose in diabetics. Ann NY Acad Sci 1985;447:389–93.
9. Koutsikos D, Agroyannis B, Tzanatos-Exarchou H. Biotin for diabetic
peripheral neuropathy. Biomed Pharmacother 1990;44:511–4.
10. Hochman LG, Scher RK, Meyerson MS. Brittle nails: response to daily
biotin supplementation. Cutis 1993;51:303–5.
11. Somer E. The Essential Guide to Vitamins and Minerals. New
York: Harper, 1995, 70–2.
12. Zempleni J, Mock DM. Biotin biochemistry and human requirements.
J Nutr Biochem 1999;10:128–38 [review].
13. Debourdeau PM, Djezzar S, Estival JL, et al. Life-threatening
eosinophilic pleuropericardial effusion related to vitamins B5 and H. Ann