I have normal skin, I'm not acne prone. I started taking biotin supplements and then hair/nail growth supplements with a large amount of biotin and had no adverse reactions for about 3 months. And then all holy h*ll broke out on my face! Even though I immediately stopped taking the supplements I went through the worst bout of acne I've ever had for a little over 6 months. At any given time I could point out 3 large pimples on my forehead. One would heal and another popped up. I tried every product on the market and nothing helped until I started using Proactive (that stuff worked like a charm, too bad it took so long to buy it). I guess it took a long time for it to get out of my system because it has taken about a year for my skin to go back to normal and I have just recently stopped using Proactive and successfully went back to CeraVe. Now just the ocassional aunt flo blemish. I wonder if this happened to anyone else?