Biotin can be completely absorbed by the body. The member of the B-vitamin family, often referred to as B7, is available in small amounts in a variety of foods, although the highest quantities can be found in brewer's yeast, egg yolk, liver, kidney, pancreas, milk, soya, and barley. Biotin is involved in the metabolization, tolerance, and utilization of glucose. It also works to decrease the resistance of insulin. Biotin function is necessary for fatty acid synthesis and the metabolism of propionate. There is also evidence of antioxidant capability. It is believed that biotin can be stored in the mitochondria. Biotin is active throughout the body and is rarely deficient.
Biotin absorption and effectiveness can be decreased when combined with various drugs such as antibiotics and anticonvulsants (carbamazepine, phenobarbital, phenytoin, and primidone). Pantothenic Acid and Biotin use the same carrier; as a result, when used together, they hinder the absorption and function of one another.
Biotin, when taken in the recommended dosage (typically around 10 mg per day) has seen no adverse side effects. There has been one reported incident of eosinophilic pleuropericardial effusion when high doses of biotin and pantothenic acid were taken simultaneously for an extended period of time. There was no conclusive evidence to indicate whether the high dosage of biotin alone was the cause.