i began taking 3,000mcg biotin, but when the bottle ran out, i mistakenly purchased a 300mcg bottle and my hair shed like crazy after a month on them...i'm talking so bad, i had to chop it off to the shoulders and begin again...
now its been a year on 5,000 biotin and its so thick and course i have to leave the relaxer on longer to get it to straighten. i also use more of the relaxer than i normally would.
and my nails are hard and thick.
i dont think it makes the hair grow faster, but definitely thicker. great for retention!