We use essential cookies (authentication, your saved goals/stack) by default. With your permission we'll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies
Drs3.1
Drostanolone (Masteron) Research
Mostly mechanism / observationalLimited safety
6 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most Drostanolone (Masteron) studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality studies published 1975–1995.
Based on 6 studies
Confidence
Low
By outcome
Men's vitality
Mostly mechanism / observational6 studies
Breast cancer (historical/obsolete)
Mostly mechanism / observational3 studies
Lean mass & physique (claimed, unproven)
Too few graded studies2 studies
Older research base
Newest study from 1995
197519851995
1Open-Label1975
In the premenopausal group, 44% responded to Masteril and 22% to oophorectomy... In the postmenopausal group, 57% responded to oestrogens and 38,5% to Masteril... Masteril has been shown to be a useful and safe agent for all age groups, even though it may appear to be less effective than oestrogens in the postmenopausal patients.
Bennett MB, Helman P, Palmer P. · S Afr Med J (1975)
Pivotal human outcome anchor for the only validated (now obsolete) indication: a 1968-1972 trial of drostanolone propionate (Masteril) in breast cancer across pre-, peri- and postmenopausal women
Premenopausal: 44% responded to Masteril vs 22% to oophorectomy; perimenopausal: 34.5% vs 39% for nandrolone phenylpropionate; postmenopausal: 38.5% vs 57% for ethinyl estradiol
Authors called it 'useful and safe' but explicitly LESS effective than estrogens in postmenopausal disease — an honest, mixed result
2In Vitro1983
These data demonstrate significant additive growth-inhibitory activity of 5-FU and MDTP in combination against MCF-7 in vitro, thus affirming their antitumor effects in vivo.
Fujita H, Teller MN, Green S, Kreis W. · Eur J Cancer Clin Oncol (1983)
Mechanistic/outcome anchor for the anti-estrogenic anti-tumour signal: 2α-methyl-DHT propionate (drostanolone propionate, 'MDTP') inhibited growth of human MCF-7 breast-carcinoma cells in vitro
MDTP produced 16-94% growth inhibition over its tested dose range and was additive/synergistic with 5-fluorouracil
Demonstrates a direct anti-proliferative effect on a human estrogen-responsive breast-cancer line, consistent with its non-aromatizable, anti-estrogenic DHT pharmacology
Administration of MDTP at 1.25 to 5 mg/kg/day yielded 15 to 48% tumor CR [complete remission]... Therapy with the cytotoxic drug 5-FUra in combination with the androgen analog MDTP is highly efficacious against induced mammary carcinomas.
Teller MN, Stock CC, Bowie M, Chou TC, Budinger JM. · Cancer Res (1982)
Foundational animal-efficacy study: drostanolone propionate ('MDTP') induced 15-48% complete remissions of carcinogen-induced rat mammary carcinomas as a single agent
Combined with 5-fluorouracil it produced 75-96% complete remissions with marked synergism, controlling new-tumour appearance
Establishes the in-vivo anti-mammary-tumour activity of the DHT-class androgen that underpinned its clinical breast-cancer use
4In Vitro1992
The major metabolites of mesterolone and drostanolone were identified as 1 alpha-methyl-androsterone and 2 alpha-methyl-androsterone, respectively.
de Boer D, de Jong EG, Maes RA, van Rossum JM. · J Steroid Biochem Mol Biol (1992)
Foundational pharmacology/identity anchor: characterizes drostanolone as 2α-methyl-17β-hydroxy-5α-androstan-3-one — a methyl-DHT, confirming the non-aromatizable DHT-derivative chemistry
Defines its urinary metabolites (chiefly 2α-methyl-androsterone) for anti-doping detection
The compound was characterized specifically to add it to doping-control procedures — underscoring that it is a doping agent, not a therapeutic
A comparison of drostanolone propionate (Masteril) and nandrolone decanoate (Deca-durabolin) in the treatment of breast carcinoma.
Chowdhury MS, Banks AJ, Bond WH, Jones WG, Ward HW. · Clin Oncol (1976)
Randomized comparative trial placing drostanolone propionate (Masteril) against another anabolic-androgenic steroid, nandrolone decanoate, in breast carcinoma
Represents the era's androgen-vs-androgen comparisons before tamoxifen/aromatase inhibitors became standard — the obsolete therapeutic context
Confirms drostanolone propionate was a genuine, trialled hormonal cancer therapy, not a modern physique compound
6Observational1995
From 1990 on, a wide range of mostly injectable steroids including nandrolone, metenolone, drostanolone and testosterone were administered. Polydrug abuse including several anabolics in combination with stimulants and diuretics was also widespread.
Delbeke FT, Desmet N, Debackere M. · Int J Sports Med (1995)
Mandatory counter-evidence on the modern use: doping-control surveillance of competing bodybuilders found drostanolone among the injectable steroids abused — documenting the off-label physique use WITHOUT any evidence of benefit
Up to 38-58% of controlled athletes in some federations tested positive; polydrug abuse (anabolics + stimulants + diuretics) was widespread
Confirms that drostanolone's contemporary life is illicit doping, not a trialled physique intervention — there are no human performance or body-composition trials to cite