"i love doxycycline for acne. it is the only thing that gave me clear skin. i wish i was okay with taking it daily for the rest of my life. but taking any antibiotic long term is bad for both the body and environment.  i did for vanity purposes, take doxycycline for a year. my skin looked amazing the entire time i was on it.  when i quit taking it, all my adult acne came back. if you are considering it for acne, i can you it was incredibly effective.  my face misses it greatly. i started out taking 100 mg in the am and 100 mg in the pm. that upset my tummy, so i went down to just 100 my once a day and it worked great."