Drostanolone (Masteron) for Anti-Estrogenic Anabolic Support — Anabolic Steroids

DHT-derived injectable AAS with anti-estrogenic properties. Originally developed for breast cancer treatment.

Overview

Drostanolone (Masteron) is a DHT-derived injectable anabolic steroid originally developed by Syntex in the 1950s and marketed as Dromostanolone Propionate (Masteron) for the treatment of inoperable breast cancer in postmenopausal women. It possesses inherent anti-estrogenic properties due to its DHT backbone, acting as a mild aromatase inhibitor without being an AI drug. Available in two ester forms - propionate (short-acting, 2-3 day half-life) and enanthate (longer-acting, 7-10 day half-life) - Masteron produces a lean, hard, dry appearance due to its non-aromatizing nature and anti-estrogenic effects. It is NOT 17-alpha-alkylated, making it non-hepatotoxic. Masteron has moderate anabolic potency (62:25 anabolic-to-androgenic ratio) and is most effective in already-lean individuals. It has been largely discontinued from pharmaceutical production for breast cancer due to the availability of better anti-estrogen drugs.

Indications

  • Inoperable breast cancer in postmenopausal women (historical medical use)
  • Anti-estrogenic anabolic support without aromatase inhibitor drugs
  • Lean physique refinement and muscle hardening
  • Estrogen management adjunct during testosterone therapy
  • Strength enhancement without water retention
  • Body composition optimization in lean individuals

Mechanism of Action

Desire for lean muscle hardening with estrogen management properties, or historical breast cancer treatment

Dosing

CompoundDoseFrequencyNotes
Drostanolone Propionate100 mgEvery other dayShort-acting propionate ester; provides anti-estrogenic and hardening effects
Drostanolone Enanthate200-400 mgOnce or twice weeklyLonger-acting enanthate ester for weekly dosing convenience

Evidence Grade

GRADE D

Safety & Contraindications

  • Not 17-alpha-alkylated - NOT hepatotoxic (advantage over oral AAS)
  • Schedule III controlled substance
  • Androgenic side effects: hair loss acceleration, acne, body hair growth
  • Virilization risk in females (was used medically but at low doses)
  • Does NOT aromatize - no estrogenic side effects
  • Anti-estrogenic properties may lower estradiol - monitor for low-E2 symptoms
  • Suppresses natural testosterone production
  • Less effective in individuals with higher body fat percentage
  • Propionate ester causes more injection site discomfort than enanthate
  • Monitor lipid profile - can adversely affect cholesterol