What does it do?
Biotin, a water-soluble B vitamin, acts as a coenzyme during 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 produce significant amounts of
biotin, which is probably available for absorption and use by the
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, anemia, and nausea. Long-term use of anti-seizure medications
may also lead to biotin deficiency. 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 individuals remains
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
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
by lowering blood glucose levels and preventing diabetic
neuropathy.Biotin in the amount of 2.5 mg per day strengthened the fingernails of
two-thirds of the individuals with brittle
nails, according to one clinical trial.
Are there any side effects or
interactions? Excess intake of biotin is excreted in the urine; no
toxicity symptoms have been reported.
works with some other B vitamins, such as folic
acid (also known as vitamin B5), and vitamin
B12; however, no solid evidence indicates that people supplementing
with biotin need to also take these other vitamins. Symptoms of
pantothenic acid or zinc
deficiency have been reported to be lessened with biotin, though people with these
deficiencies should supplement with the nutrients they are deficient in.
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