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.1 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.2, 3 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 trial.4
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.5
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,6anemia, and nausea. Long-term use of anti-seizure medications may also lead to biotin deficiency.7Alcoholics and people 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.8 In animals, and possibly in humans, biotin deficiency can cause birth defects.9 As biotin deficiency may occur in as many as 50% of pregnant women,10 it seems reasonable to use a prenatal multiple vitamin and mineral formula that contains biotin.
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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2025.