"ive been on doxycycline for almost about a month now and over all it did pretty well. i&#039;m 22 years old and i&#039;ve been battling acne since i was 18. i initially had pretty bad cystic acne from 18 to 20 years old. i was on 2 rounds of accutane before i got on doxy. the only real side effects that i experienced were facial redness and dryness. the acne started clearing up 2 weeks in the routine. i was 100mg twice a day going on to 50mg. for the most part the medication works just highly recommend drinking a lot of water and loading up on the sunscreen/moisturizer."