Biotin is a water-soluble B vitamin that plays an important role in metabolizing the energy we get from food. Biotin assists four essential enzymes that break down fats, carbohydrates, and proteins.

Biotin deficiency is rare, except, possibly, among pregnant women. All proposed therapeutic uses of biotin supplements are highly speculative.

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* Requirements/Sources  

Although biotin is a necessary nutrient, we usually get enough from bacteria living in the digestive tract. Severe biotin deficiency has been seen in people who frequently eat large quantities of raw egg white. Raw egg white contains a protein that blocks the absorption of biotin. Fortunately, cooked egg white does not present this problem.

The official US and Canadian recommendations for daily intake of biotin are as follows:

  • Infants
    • 0-5 months: 5 mcg
    • 6-11 months: 6 mcg
  • Children
    • 1-3 years: 8 mcg
    • 4-8 years: 12 mcg
    • 9-13 years: 20 mcg
  • Males and Females
    • 14-18 years: 25 mcg
    • 19 years and older: 30 mcg
  • Pregnant Women: 30 mcg
  • Nursing Women: 35 mcg

Good dietary sources of biotin include brewer's yeast, nutritional (torula) yeast, whole grains, nuts, egg yolks, sardines, legumes, liver, cauliflower, bananas, and mushrooms.

There is some evidence that slight biotin deficiency may tend to occur during normal pregnancy. 9 For this reason, pregnant women are advised to take a prenatal vitamin that contains the recommended amount of biotin.

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Therapeutic Dosages  

For people with diabetes, the usual recommended dosage of biotin is 7,000 to 15,000 mcg daily.

For treating "cradle cap" (a scaly head rash often found in infants), the usual dosage of biotin is 6,000 mcg daily, given to the nursing mother (not the child). A lower dosage of 3,000 mcg daily is used to treat brittle fingernails and toenails.

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Therapeutic Uses  

All the proposed uses of biotin discussed here are speculative, based on highly incomplete evidence.

Preliminary research suggests that supplemental biotin might help reduce blood sugar levels in people with either type 1 (childhood onset) or type 2 (adult onset) diabetes , 1,2 and possibly reduce the symptoms of diabetic neuropathy . 3 However, no double-blind, placebo-controlled studies have been reported on these potential uses of biotin. (For why double-blind trials are so important, see Why Does This Database Rely on Double-blind Studies? ) Two double-blind studies have found benefit for diabetes with a mixture of biotin and chromium10,11 ; however, it is not clear how much the biotin in this combination contributed.

Very weak evidence, too weak to rely upon at all, has been used to support that theory that biotin supplements are helpful for brittle nails . 4,5,6

On the basis of virtually no evidence at all, biotin has been proposed for treating cradle cap in infants.

There are indirect indications that individuals taking antiseizure medications might benefit from biotin supplementation at nutritional doses. 7,8 However, it has been suggested that biotin should be taken at least 2 hours before or after the medication dose, to avoid potential interference with the medication's absorption. In addition, excessive biotin supplementation (above nutritional needs) should be avoided, because it might possibly interfere with seizure control. Note: All these proposed interactions are quite speculative, and even if they do exist, may not be important enough to make a difference in real life.

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Safety Issues  

Biotin appears to be quite safe. However, maximum safe dosages for young children, pregnant or nursing women, or those with severe liver or kidney disease have not been established.

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Interactions You Should Know About  

If you are taking:

  • Anticonvulsant medications : You may need extra biotin, but do not take more than the dosage recommendations listed in the Requirements/Sources section. In addition, take the vitamin 2 to 3 hours apart from the medication.