"i have been using doxycycline for moderate and persistent acne for two weeks and have noticed a slight difference. i seem to have less breakouts than before taking this medication. i haven&#039;t seen any dramatic results though and i didn&#039;t expect to in such a short space of time. hopefully after another month or so on the medication i&#039;ll see better results. i haven&#039;t got any side effects other than a slight stomach cramp when i take the medication without food. i am waiting for a referral to see a dermatologist so hopefully i will get this problem sorted."