Injectable Steroid

Drostanolone Propionate

  • CAS 521-12-0
  • Formula C23H36O3
  • Half-life 2.5 days (IM)
  • Detection 3 weeks
Chemical structure of Drostanolone Propionate
PubChem CID 224004 ↗

Clinical Notes

Mechanism, kinetics, and protocol-relevant pharmacology — reviewed by the editorial pharmacology lead.

DHT-derived injectable — 2alpha-methyl modification at the A-ring confers resistance to 3alpha-HSD, allowing intact muscle-cell activity. Cannot aromatise. Weak AR binding in skeletal tissue but displaces estradiol from SHBG, increasing free-testosterone fraction of any concurrent testosterone — this is the mechanism behind the hardening clinical picture at low body-fat percentages. Effect is visibly null above 15% body fat; below 12%, the lean-tissue definition response becomes dose-responsive. Propionate ester mandates EOD injection schedule; PIP is common and dose-dependent — low-viscosity MCT or GSO carrier oil reduces it materially. Androgenic effects (scalp, prostate) occur but are limited to DHT-sensitive populations.

Chemical Identity

CAS Number 521-12-0
IUPAC Name [(2R,5S,8R,9S,10S,13S,14S,17S)-2,10,13-trimethyl-3-oxo-1,2,4,5,6,7,8,9,11,12,14,15,16,17-tetradecahydrocyclopenta[a]phenanthren-17-yl] propanoate
Molecular Formula C23H36O3
Molecular Weight 360.53 g/mol
SMILES CCC(=O)O[C@@H]1CC[C@@H]2[C@H]3CC[C@@H]4CC(=O)[C@@H](C)C[C@]4(C)[C@@H]3CC[C@]12C
InChIKey VDIINQKPRNWKEH-GOGNSEEVSA-N
Melting Point 124-126 °C
Solubility Insoluble in water; soluble in oils
Half-life 2.5 days (IM)

Pharmacological Profile

Anabolic Rating 62
Androgenic Rating 25
Aromatisation None
Hepatotoxicity None
Detection Window 3 weeks

Known trade names

  • Masteron
  • Drostopro
  • Mastabol

External references

Data sourced from peer-reviewed pharmacological literature and authoritative chemical databases (PubChem, DrugBank, ChEBI). Provided for identification and research reference only — not medical advice.