"i started taking this when i was 17 years old (now almost 22) and ordinary antibiotics weren&#039;t helping my acne problems. before, i had unpredictable periods (often skipping once every several months for no reason), painful cramps, and a period lasting up to 7 whole days. now i have a 99% clear face, a regular light-medium period lasting 4-5 days and no cramps! i am not sexually active (never have been), so i&#039;m not sure how effective it is for me actual birth control-wise, but my sex drive is much lower. i may end up finding a new brand once i get married later this year because of this side effect alone."