This matrix of compounds including 17a-methyl-baET works by inhibiting a natural enzyme to lower muscle destroying cortisol levels in the muscle tissue. Cortisol is the number one reason for losing muscle mass after an anabolic compound cycle. Retain also increase T-3 production from the thyroid which causes an increase in metabolism and fat-loss. This is the only post cycle product to ever keep your body in an anabolic state while cutting fat, to get you completely shredded. When combined with PCT and proper diet, most users report no post-cycle muscle loss and up to a 3% drop in body fat.