Mastabol 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. Mastabol 100 Depot combines the fast-acting propionate form with the longer acting enanthate form.