Drostanolone (also known as dromostanolone) is a modified form of dihydrotestosterone. It differs by the introduction of a methyl group at carbon-2 (alpha), which considerably increases the anabolic strength of the steroid by heightening its resistance to metabolism by the 3-hydroxysteoid dehydrogenase enzyme in skeletal muscle tissue. Drostanolone enenthate is a modified form of drostanolone, where a carboxylic acid ester (propionic acid) has been attached to the 17-beta hydroxyl group. Esterified steroids are less polar than free steroid, and are absorbed more slowly from the area of injection. Once in the bloodstream, the ester is removed to yield free (active) drostanolone. Esterified steroids are designed to prolong the window of therapeutic effect following administration, allowing for a less frequent injection schedule compared to injections of free (unesterified) steroid. The half-life of drostanolone enanthate is approximately 8 days after injection. Drostnolone is most often used by bodybuilders and athletes in speed sports, where it is highly favored for its ability to produce solid increases in lean muscle mass and strength, which are usually accompanied by reductions in body fat level and minimal side effects. For physique or performance-enhancing purposes, this drug is usually injected three times per week and dosages in the range of 200-600mg per week are sufficient to provide measurable gains in lean muscle mass and strength.