Educational reference only. Informational material drawn from peer-reviewed literature. Not medical advice and not a recommendation to use, dose, or modify any therapy. Decisions about hormone therapy should be made with a qualified healthcare provider.
Overview
Overview
Drostanolone is a synthetic anabolic-androgenic steroid (AAS) derived from dihydrotestosterone (DHT). It is best known by the trade name Masteron, originally introduced in the late 1950s and used clinically through the 1980s as a palliative treatment for advanced inoperable breast cancer in postmenopausal women. It is no longer approved for human therapeutic use in the United States and has been discontinued by its original manufacturers, though it remains widely produced through unregulated channels for non-medical use.
Structurally, drostanolone is 2α-methyl-dihydrotestosterone: DHT with a methyl group added at the C2α position. This modification confers two key properties: it cannot be aromatized to estrogen (the structure prevents aromatase from acting on it), and it resists metabolic inactivation by the enzyme 3α-hydroxysteroid dehydrogenase, which normally degrades DHT in muscle tissue.
Once cleaved from the ester, the drostanolone molecule itself has a much shorter half-life, measured in hours rather than days. The ester is purely a release-rate modifier.
Forms
Available forms & half-lives
| Form | Approximate half-life |
|---|---|
| Propionate | ~2 days |
| Enanthate | ~7–10 days |
What it does
Main effects
- Modestly anabolic effect on skeletal muscle; characteristically more androgenic than anabolic relative to testosterone
- No aromatization to estrogen: does not produce water retention, gynecomastia, or other estrogen-mediated effects from itself
- Weak anti-estrogenic activity: competitive binding at the estrogen receptor and modest aromatase inhibition; the original basis of breast-cancer use
- Increased free testosterone fraction via competitive displacement from SHBG when co-administered with testosterone
- Reputation for muscular hardness / density during cutting phases, largely a consequence of reduced water retention rather than direct fat loss
- Resistance to 3α-HSD inactivation in muscle tissue: drostanolone persists at active levels longer than unmodified DHT
What to watch for
Common side effects
- HDL cholesterol reduction: significant and reliable across DHT-derivative AAS; often more pronounced than with testosterone PMC: 2439524
- HPG axis suppression: full suppression of LH, FSH, and endogenous testosterone at typical performance doses; recovery is variable
- Possible accelerated scalp hair loss: hair loss is commonly reported in drostanolone users, but direct attribution to drostanolone itself is not well-established. A likely mechanism is SHBG suppression by drostanolone, which raises free testosterone and increases scalp DHT via 5α-reductase. Under this model, 5α-reductase inhibitors (finasteride, dutasteride) may still be useful for hair-loss control when drostanolone is stacked with testosterone or other aromatizable compounds.
- Acne and oily skin: often more severe than with testosterone due to DHT-derivative androgenic potency
- Prostate growth and PSA elevation: direct DHT-mediated effects
- Severe virilization in women: voice deepening and clitoral enlargement are often partially or fully irreversible
- Unregulated supply chain risks: no FDA-regulated drostanolone product currently exists; underground-lab purity, dosing accuracy, and sterility cannot be assumed
Key facts
Key facts worth knowing
- Drostanolone cannot aromatize to estrogen due to its structural modifications. This is the distinguishing pharmacologic feature that drove its original use in breast cancer and its modern non-medical use as a "dry" compound. ChemicalBook, 2024
- Beyond its inability to aromatize, drostanolone may have weak aromatase-inhibiting activity itself, contributing to the suppression of circulating estrogen in users who are simultaneously running aromatizable compounds.
- The original FDA-approved indication was palliative treatment of inoperable, metastatic breast cancer in postmenopausal women. It was supplanted in the 1990s by more effective and better-tolerated agents (tamoxifen, then the aromatase inhibitors).
- As a DHT derivative, drostanolone carries the androgenic side effect profile typical of DHT compounds: acne, oily skin, accelerated androgenic alopecia in genetically predisposed individuals, and significant virilization risk in women.
- Because drostanolone is no longer manufactured by FDA-regulated pharmaceutical companies for human use, all product encountered in non-medical contexts is from unregulated unregulated producers, with the associated purity, dosing accuracy, and sterility concerns that implies.
Legal status
Legal status
Schedule III controlled substance in the United States (DEA). No current FDA approval for any indication. WADA-prohibited at all times in competitive sport.