Drostanolone (Masteron)

Drostanolone (dromostanolone) is a synthetic anabolic–androgenic steroid derived from dihydrotestosterone (DHT). Chemically, it is DHT with a methyl group at the 2α position. It acts as an androgen receptor (AR) agonist, stimulating protein synthesis in muscle. Unlike testosterone, drostanolone does not aromatize into estrogen, so it produces no estrogenic effects (no gynecomastia or water retention). It also is not a substrate for 5α-reductase or 3α-HSD enzymes, giving it a high anabolic-to-androgenic ratio. In practice, drostanolone is moderately anabolic and weakly androgenic (animal studies suggest an anabolic:androgenic ratio around 3–4:1). Because it is already a DHT derivative, its androgenic potency is relatively strong, but its overall muscle-building effect is milder than testosterone. Drostanolone also lowers SHBG, increasing free testosterone levels.

Drostanolone is usually administered as the propionate ester by intramuscular injection. The elimination half-life of drostanolone propionate is about 2 days. It has essentially 100% bioavailability by IM injection and undergoes hepatic metabolism before renal excretion. Because drostanolone is not 17α-alkylated, it is not inherently hepatotoxic.

Drostanolone propionate was first described in 1959 and introduced medically in 1961. Under brand names like Drolban, Masteril, and Masteron, it was used as hormonal therapy for advanced breast cancer in women. It was approved as an antiestrogenic agent because it binds AR in tumor cells and interferes with estrogen-driven growth. Drostanolone’s relatively lower virilizing effect (vs. testosterone) made it preferable for female cancer patients. However, with newer treatments available, Masteron was eventually discontinued and is no longer marketed for clinical use. Today it has no approved medical indication.

In bodybuilding, Masteron is prized for its ability to yield a very hard, dry, and “ripped” physique. Since it does not convert to estrogen, muscles appear denser and more vascular. Athletes report it gives a “chiseled” look by reducing water retention and enhancing definition. Masteron is most often used during cutting cycles (fat loss phases) or late in a contest-prep cycle to preserve muscle while dieting. Its effects include moderate lean muscle gain and noticeably improved muscle hardness, rather than big size increases.

Key points about performance use include:
- DHT-derived, non-aromatizing: no estrogenic effects means no water weight or gyno.
- Dry, hard look: enhances vascularity and definition when body fat is low.
- Moderate anabolism: not as bulky as other steroids, but refines existing muscle mass.
- High androgenicity: produces pronounced strength and density gains without softness.

Masteron is available with short (propionate) or long (enanthate) esters. The propionate form requires frequent injections (due to its ~2-day half-life) while the enanthate form lasts ~7–10 days per injection. Bodybuilders often stack Masteron with other steroids. Common combinations are adding it to testosterone or trenbolone during a cut to increase hardness and offset estrogenic side effects. It is also paired with other “cutting” drugs like Winstrol or Anavar to maximize muscle definition. Users find that Masteron can make a “dry stack” (testosterone + Masteron) particularly effective.

Anecdotally, users report that Masteron produces lean gains of quality muscle rather than large bulk. Strength may increase moderately, but the main benefit is the sculpted, vascular appearance. Many note a surge in confidence and intensity during workouts. Effects on libido and mood vary. Some bodybuilders feel increased aggression or drive, while others experience mood swings or irritability. Libido often goes “either way”: it can increase (due to strong androgenic action) or decrease (especially if stacked with aromatase inhibitors or used at high dose). Vascularity typically improves; veins often appear more prominent on Masteron. Recovery from training is somewhat enhanced (like most steroids), but Masteron is not known primarily as a “recovery” drug.

Masteron’s side effects mainly reflect its androgenic nature. Common androgenic and general side effects include:
- Hair loss: It can accelerate male-pattern baldness in genetically susceptible users.
- Acne and oily skin: Increased sebum production often causes acne outbreaks.
- Virilization (in women): Females may develop facial hair, deepen their voice, and experience other masculinizing effects.
- Mood changes: Many users report increased aggression or mood swings on Masteron.
- Prostate effects: As a DHT-derivative, it may enlarge the prostate in men, potentially worsening benign prostatic hyperplasia.

Cardiovascular: Like other injectable AAS, drostanolone can unfavorably alter cholesterol: it typically lowers HDL (“good” cholesterol) and raises LDL (“bad” cholesterol), increasing atherosclerosis risk. It may also mildly raise blood pressure in some users.

Estrogenic profile: Drostanolone does not aromatize, so it has virtually no estrogenic side effects (no gynecomastia or bloat). In fact, it can suppress overall estrogen levels. Low estrogen can cause issues like joint stiffness, low sex drive, or mood lability if not managed.

Liver toxicity: Because Masteron is not 17α-alkylated, it is not highly hepatotoxic. Unlike oral AAS, it does not cause major liver damage. However, heavy or long-term abuse can still strain the liver, and cases of mild enzyme elevations have been reported.

Hormonal suppression: As with any AAS, Masteron strongly suppresses endogenous testosterone. Long-term use can lead to testicular atrophy, infertility, and hypogonadism after the cycle ends. Reduced natural testosterone production causes post-cycle libido drop and fatigue. Proper post-cycle therapy is needed to help recover normal hormone levels.

Typical masculine dosing of Masteron propionate is about 200–400 mg per week, split into 2–3 injections (e.g. 100 mg every other day). For the enanthate form (less common), users might take 300–500 mg weekly in 1–2 doses. Female athletes (who face high virilization risk) might use only about 50–100 mg/week, though use by women is generally discouraged. A standard Masteron cycle lasts 4–8 weeks, often aligned with contest preparation or the latter part of a cutting cycle. Longer use is possible but increases side effect risk. Because of its short half-life, propionate dosing requires frequent shots, whereas the enanthate ester can be injected weekly.

Drostanolone and its esters are controlled substances in most countries. In the United States, drostanolone is a Schedule III anabolic steroid under the Controlled Substances Act. In Canada, it is listed as Schedule IV. In the United Kingdom, drostanolone (and all AAS) is a Class C drug (Schedule 4, Part II of the Misuse of Drugs Act), meaning possession without prescription is illegal. In Australia, drostanolone is regulated by the Office of Drug Control and requires special import licensing even for medical use. The EU has no approved Masteron medicines; possession or supply without authorization is prohibited in EU countries. All major sports authorities ban drostanolone under anti-doping rules.