I took perfectil and 6500 mcg biotin and I didn't have any adverse reactions. Perfectil is a hair, skin and nail supplement. Now I'm taking prenatals because I'm getting ready to get pregnant and also perfectil is like $17.00 a month so right now I can't afford it. I really liked it when I was taking it. I only took it for one month but I could already see a difference in my hair and my nails were really hard and grew really fast. I would've loved to see what would've happened if I took it for months. Let us know how you like it!!!