Minocycline
"This works and works very fast. It clears my acne completely in anywhere from 2-5 days, depending on how bad the outbreak. It's shocking how fast it works. I'm 43 and over the years tried everything to clear up bad cystic acne. My diet is fantastic, lots of fruits and veggies/no processed food. Tried every topical product out there,  vitamins, you name it. I always break out and always get immediately clear with minocycline. I will keep trying non antibiotic approaches,  but so far,  nothing else comes even close. 

I tried doxycycline twice.   As another reviewer said,  it took much longer to do what minocycline does for acne."