1-ad is the only prohormone that works, i've got a sensitive stomache, have taken about 4 bottles of 1-ad, sometimes 2 or 3 at a time and never had any stomache problems. I did have urine burn a couple times but nothing unbearable for sure. I would never ditch my 1-ad for another product. The results i've gotten have been dramatic to say the least. It's well worth it in my book.