Overview
Masteron Propionate is a DHT-derivative injectable anabolic-androgenic steroid. It has a half-life of ~2.5 days (60 hours). It is classified under testosterone derivatives in Milligram's compound library, with full pharmacokinetic curve modeling based on its ~2.5 days (60 hours) half-life.
With a half-life of ~2.5 days (60 hours), Masteron Propionate supports less frequent dosing schedules. Administered via IM injection, it has a bioavailability of approximately 95% via its primary route.
Half-life approximately 60 hours. Does not undergo aromatization. One-compartment model. Peak plasma at ~18 hours.
Mechanism of Action
Masteron Propionate's pharmacological activity involves the following key pathways:
Androgen Receptor Binding
Masteron Propionate binds to androgen receptors in skeletal muscle and other tissues, initiating transcription of androgen-responsive genes involved in protein synthesis and nitrogen retention.
Non-Aromatizing
Masteron Propionate does not undergo aromatization to estrogen, which is a distinguishing pharmacological property among anabolic compounds.
Ester Hydrolysis
After injection, the ester bond is cleaved by esterase enzymes, releasing free testosterone into circulation. The ester length determines the rate of release and thus the half-life.
Dosing Protocols
The following protocols represent commonly observed dosing patterns. These are observational summaries, not recommendations.
Dose
150 mg/week
Route
Intramuscular
Frequency
Every other day
Duration
8-16 weeks
Dose
500 mg/week
Route
Intramuscular
Frequency
Every other day
Duration
8-16 weeks
Frequently Asked Questions
What is Masteron (Drostanolone Propionate) and what is it used for?
Masteron is the trade name for drostanolone propionate – a synthetic anabolic–androgenic steroid derived from dihydrotestosterone (DHT). Originally developed as a treatment for inoperable breast cancer in women due to its anti-estrogenic properties, it became widely used in competitive bodybuilding for its ability to produce a hard, dry, vascular physique without contributing to estrogenic side effects. Because it is already a 5α-reduced compound, it does not convert to estrogen or to a more potent androgen via 5α-reductase.
What is the half-life of Masteron Propionate and how often does it need to be injected?
Drostanolone propionate has a short elimination half-life of approximately 2–3 days. This requires frequent injections – every other day (EOD) is the standard protocol – to maintain stable plasma levels and avoid wide peak-to-trough swings. Users who find EOD dosing impractical sometimes opt for Masteron Enanthate, which shares the same active compound but requires only 1–2 injections per week.
How does Masteron reduce estrogenic effects?
Drostanolone acts as a mild competitive inhibitor of the aromatase enzyme, reducing the conversion of testosterone and other aromatizable androgens to estrogen. It also strongly binds to sex hormone-binding globulin (SHBG), displacing testosterone and increasing the proportion of free, biologically active testosterone in circulation. These two mechanisms work together to produce a drier, harder appearance and help buffer estrogen-related effects when stacked with aromatizing compounds.
What compounds is Masteron Propionate commonly stacked with?
Masteron Propionate is most frequently used in cutting or recomposition phases alongside Testosterone Propionate (for matching injection schedules), Trenbolone Acetate, Anavar, and Winstrol. It is rarely run as a solo compound due to its suppressive nature and moderate anabolic activity on its own. When paired with testosterone, Masteron's SHBG-binding action increases the effective free testosterone concentration from the base dose.
Does Masteron cause hair loss?
Because drostanolone is a DHT derivative – and already in its most potent androgenic form – it can accelerate hair loss in individuals genetically predisposed to androgenic alopecia. Unlike testosterone, there is no upstream conversion step to block: 5α-reductase inhibitors such as finasteride or dutasteride are ineffective against Masteron-induced scalp androgenic activity. The compound interacts directly with follicular androgen receptors in susceptible individuals.
What is the typical dose and cycle length for Masteron Propionate?
Community-reported dosing ranges from 300–500 mg per week, typically structured as 100 mg injected every other day. Cycle duration is generally 8–12 weeks. Because of its 2–3 day half-life, steady state is reached within approximately 10 days of starting – meaning effects become apparent relatively quickly compared to longer-ester compounds.