Not really, masteron is “anabolic” whilst proviron isn’t. Inactivation by 3b-HSD within skeletal muscle renders mesterolone inactive with regards to anabolic activity. Furthermore the oral bioavailability of mesterolone is rather low (around 3%) as it isn’t c-17 alpha alkylated.
Mesterolone’s benefits are
- cosmetic
- based upon neurological alteration
Drostanolone fits 1 + 2 and (directly) adds lean tissue.
They’re structurally similar though (2a methyl dihydrotestostosterone vs 1a methyl dihydrotestosterone). Slight alterations in hormonal structure can make a HUGE difference. Good example would be EQ (dehydrotestosterone) vs dbol (dehydromethyltestosterone).