Last updated: March 2026
Drostanolone (Masteron) is an injectable DHT derivative originally developed to treat inoperable breast cancer in women. Its unique anti-estrogenic properties, inability to aromatize, and lean-hardening effects made it popular in competitive bodybuilding. This educational reference covers its clinical history, pharmacology, and harm reduction context.
Masteron is a 2α-methylated DHT derivative. The 2α-methyl group prevents inactivation in muscle tissue, making it more anabolic than unmodified DHT while retaining the non-aromatizing, anti-estrogenic properties of DHT.
As a DHT derivative, drostanolone cannot be aromatized to estradiol. Aromatase cannot metabolize DHT-derived structures. This makes Masteron inherently non-estrogenic — no water retention, no gynecomastia risk from the compound itself. At competition prep body fat levels (<10%), this produces the characteristic dry, vascular, dense appearance.
Beyond simply not aromatizing itself, drostanolone competitively inhibits aromatase activity, partially blocking the conversion of other androgens (testosterone, androstenedione) to estrogens. When stacked with testosterone, Masteron can meaningfully reduce the aromatase-mediated estradiol increase from testosterone. This anti-estrogenic activity was the basis of its original breast cancer use.
Unmodified DHT is rapidly inactivated by 3α-hydroxysteroid dehydrogenase (3α-HSD) in muscle tissue. The 2α-methyl group in drostanolone blocks this inactivation, allowing drostanolone to exert androgen receptor activity in muscle. This makes it genuinely anabolic — unlike pure DHT — though its anabolic potency is moderate compared to testosterone.
Like all DHT derivatives, drostanolone has significant SHBG-binding affinity. By occupying SHBG sites, it increases the free fraction of co-administered testosterone, enhancing its bioavailability. When stacked with testosterone (the most common use pattern), this SHBG-mediated testosterone potentiation adds synergistic effect beyond the direct androgenic activity of drostanolone itself.
Data from breast cancer clinical trials, pharmacological research, and comparative AAS studies on drostanolone.
Essential monitoring for injectable AAS — cardiovascular health and hormonal panel tracking.
Dosing schedules, interaction warnings, and cycle protocols for 50+ compounds — all in one place.
This page is for educational and harm reduction purposes only. It is not medical advice. Drostanolone (Masteron) is a Schedule III controlled substance in the United States. While it was historically used medically for breast cancer, it is no longer approved for this use. It is banned by WADA and all major sports organizations. Use carries health risks including androgenic effects, cardiovascular disease, HPTA suppression, and male pattern baldness acceleration. MeetPeptide does not endorse or encourage the use of controlled substances. Consult a qualified physician before any decisions regarding hormone use.