Doxycycline
"A year ago my doctor prescribed Doxine (doxycycline) and I found that after about 2 weeks of taking a tablet a day and increasing my usual water consumption, my skin started getting better and much more clear. A relief after struggling with mid-teen acne. Eventually my skin was fine (3 months after starting) and I stopped, thinking that it was now my body and not the medicine that was healing my skin. But soon afterwards my acne started appearing once more, and so I began taking doxycycline again about 2 months ago. It's been great and I've really got my confidence back as my skin naturally is quite oily and acne prone. Note that while taking the medicine it is still common to get a tiny pimple or two sometimes as the drying process of the skin isn't so intense on this medication. My only side effects were my increased desire for water and a slight aversion to strong sunlight."