What is biotin used for and what are the side effects?

Another supplement..: Biotin deficiency is rare, but can occur in persons with genetic mutations, on long-term antibiotics or anti-convulsants, or who eat a lot of raw egg whites. There is no good evidence that this over-the-counter supplement is needed, because normal people eating a regular, balanced diet should get enough of it from their foods.

Vitamin: Mostly used for hair and nails. Most people have no side effects except maybe urine color change or odor.