By doing so, you'll restore your hormones and maintain the gains you've gotten. The stack contains Rebirth and Enhance, two massively stacked products designed to boost test levels, what is 99 sarms. Rebirth also contains Arimistane, a potent anti-estrogen compound that can be used as PCT. You can purchase the PCT stack by clicking here. Please note that ignoring the use of post cycle therapy could result in low testosterone, which is associated with fatigue, loss of muscle mass, and decreased sexual desire.However, bodybuilders are using them in a big way these days since they are supposed to be relatively safer as compared to steroids, what is 99 sarms.