Androsta-3,5-diene-7,17-dione occurs naturally in the human body. Its trade name is "arimistane." Androsta-3,5-diene-7,17-dione is a metabolite of 7-Keto DHEA, which does not convert into testosterone or estrogen. It permanently binds to the aromatase enzyme (part of a class of compounds called "suicide inhibitors") and prevents any estrogen rebound by destroying the actual enzyme that converts testosterone to estrogen. Without this enzyme (aromatase), your body cannot physiologically convert testosterone to estrogen. Arimistane is very effective for both on-cycle support AND PCT, and can even be used off-cycle to shed excess water weight and bloat and maintain a leaner physique. Furthermore, it has also been shown to reduce cortisol, raise LH (luteinizing hormone), and increase testosterone levels.