How come there's always much less than the recommended dose of Biotin in multivitamins?

Answer 1

Biotin is expensive. The cheap vitamins like B1 and B2 get used to make the vitamin pill look complete, but then the manufacturers skimp on the higher-cost vitamins. However, biotin, unlike many of the other vitamins, is also normally manufactured by the beneficial bacteria in your intestines, so it's not absolutely necessary to get all you need from pills or food, as long as your intestinal flora is in good shape. Antibiotics can wipe out this beneficial bacteria, and biotin deficiences, although rare, can develop if the bacteria do not re-colonize the intestines.