I took 900mcg of biotin for about three weeks recently for eyebrow growth. Although I got new eyebrow hair growth, I also developed itchy bumps along my jawline that started to spread to other areas of my face. Not pleasant! I have reduced the dosage to 300-600mcg a day (which I've been doing for a couple weeks) and I have experienced a few bumps here and there but no real itching. No obvious hair growth yet either.