I'm very late to this Biotin party, but I wanted to say that I started taking a hair and nail supplement that contains Biotin at the beginning of Dec. In Aug, about 12 months into hrt I noticed that my hair started shedding. My T and E levels were fine, and I was considering going on Finasteride. About 10 days to two weeks into taking the supplement, I noticed that my hair loss was appreciably slowing. Now, it seems to have stopped altogether. It could be coincidence. I had just separated from my spouse in Aug., and stress might have caused the hair loss. But I'm not going to stop taking the supplement anytime soon.
I'm not sure if it will help with regrowth, but not shedding will give cycling hair a chance to catch up.
Oh, and I'm only taking 2000 mcg a day. I only take 2/3 the recommended dose.