Drostanolone Propionate Product name: Drostanolone Propionate Synomym: dromostanolone propionate;Masteron prop CAS Registry Number: 521-12-0 Molecular Formula: C23H36O3 Molecular Weight: 360.53 Packing: foil bag Assay: 99% Appearance: White or white crystalline powder by Bill Roberts - Masteron (dromostanolone propionate, also known as drostanolone propionate) had formerly been a rare drug in the United States and was enjoyed principally by our European friends. This was due to never been produced in great quantity by Syntex and never being marketed in the United States.