Biotin increases cell growth, and as I have read on nutitional forums, that if you happen to have a tumour, whether it is cancerous or not, biotin will increase that growth of the tumour as well.

I take a high-potency vitamin, 1000 U.I of E, also C, and B, and in addition to my protein shakes, I add Udo's oil to it. I have a friend who doesn't take any vitamins, and we participate in the same races, and I recovery time is quite a bit less than hers. :cool: