Mastaplex 100 (Drostanolone Enanthate and Propionate) is a synthetic derivative of dihydrotestosterone, displaying a potent androgenic effect that is responsible for increases in muscle density and hardness and a moderate anabolic effect that creates a positive nitrogen balance in humans and promotes protein synthesis. Since it is a derivative of dihydrotestosterone, dromastolone does not aromatize in any dosage and thus it cannot be converted into estrogen. Therefore, estrogen-related water retention is eliminated. Mastaplex 100(Drostanolone Enanthate and Propionate) combines the fast-acting propionate form with the longer acting enanthate form. Drostanolone (trade name Masteron) is an anabolic/androgenic steroid. It is known to be highly androgenic and mildly anabolic. It is incapable of aromatization and has similar properties to dihydrotestosterone. It has been successfully used as a breast cancer drug but because of the high risk of virilization safer options are prescribed. Use in sports Masteron is used primarily by athletes who need to retain strength while losing mass. It is beneficial to runners and athletes who must remain in a certain weight class. It has gained popularity in the bodybuilding community as a diuretic and muscle defining drug. Trivia Ultimate Fighting Championship athlete Hermes Franca tested positive for use of Drostanolone following his July 7th 2007 lightweight championship bout against title holder Sean Sherk.