"i have had moderate acne since i was 16 (now 23) and i have tried just about everything i can think of and i was finally put on doxycycline 100mg to take once a day for 3 months. although i experienced headaches and nausea in the first week, it has since stopped and i feel no side effects (so stick it out for at least a week to see if they stop). i am now in the middle of the second month and although my acne has diminished a little bit, i am still getting some new pimples pop up (smaller than usual which is good), but my skin has not completely cleared. i am also on this medication for extremely bad ingrown hairs in the groin area and although the medication is helping, it hasn&#039;t stopped those either. it definitely helped though."