Overview
Primobolan Enanthate is a DHT-derivative injectable anabolic-androgenic steroid. It has a half-life of ~10.5 days (252 hours). It is classified under testosterone derivatives in Milligram's compound library, with full pharmacokinetic curve modeling based on its ~10.5 days (252 hours) half-life.
With a half-life of ~10.5 days (252 hours), Primobolan Enanthate supports less frequent dosing schedules. Administered via IM injection, it has a bioavailability of approximately 95% via its primary route.
Half-life approximately 10.5 days. Does not undergo aromatization. Low androgenic rating relative to anabolic rating. One-compartment model.
Mechanism of Action
Primobolan Enanthate's pharmacological activity involves the following key pathways:
Androgen Receptor Binding
Primobolan Enanthate 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
Primobolan Enanthate 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
Once weekly
Duration
8-16 weeks
Dose
750 mg/week
Route
Intramuscular
Frequency
Once weekly
Duration
8-16 weeks
Frequently Asked Questions
What is Primobolan Depot and how does it work?
Primobolan Depot (Methenolone Enanthate) is an injectable anabolic–androgenic steroid derived from dihydrotestosterone (DHT). It binds to androgen receptors in skeletal muscle tissue, stimulating protein synthesis and enhancing nitrogen retention – creating an environment that supports lean tissue preservation even in a caloric deficit. The enanthate ester attached to the methenolone base provides slow, sustained release from the injection depot, with a half-life of approximately 10 days.
What is the half-life of Primobolan Depot and how often should it be injected?
Methenolone Enanthate has a reported half-life of approximately 10–10.5 days. Once-weekly or twice-weekly injections are both observed in community protocols – once weekly is sufficient to maintain relatively stable plasma levels given the long ester, while twice weekly provides slightly smoother concentration curves. Steady state is reached after approximately 50 days (5 half-lives) of consistent dosing.
Does Primobolan Depot aromatise or cause estrogenic side effects?
Methenolone Enanthate does not aromatise – it cannot be converted to estrogen by the aromatase enzyme. This means estrogen-related side effects such as water retention, bloating, and gynecomastia are not directly attributable to Primobolan Depot. This non-estrogenic profile is a primary reason it is favoured for lean mass preservation and cutting phases, and why it is considered one of the milder injectable anabolic steroids in terms of estrogenic burden.
Is Primobolan Depot liver toxic?
Methenolone Enanthate is administered by intramuscular injection and bypasses first-pass hepatic metabolism. It is considered one of the least hepatotoxic anabolic steroids available – clinical and community data consistently report no meaningful liver enzyme elevations at typical doses. This is in contrast to many oral anabolic steroids, which undergo significant hepatic processing and can elevate liver enzymes.
What are the side effects of Primobolan Depot?
As a DHT-derived compound, Primobolan Depot's primary side effect profile is androgenic: scalp hair acceleration in those genetically predisposed, increased body and facial hair, and mild acne. It suppresses endogenous testosterone production via hypothalamic–pituitary axis feedback, making a testosterone base a common addition in longer protocols. Lipid changes are observed, including reduced HDL cholesterol. These effects are generally considered milder in magnitude than more potent anabolic steroids.
What compounds is Primobolan Depot commonly stacked with?
Primobolan Depot is most frequently observed stacked with a testosterone base – Testosterone Enanthate or Testosterone Cypionate – to maintain physiological testosterone levels during suppression. For cutting phases it is combined with compounds such as Masteron Enanthate, Anavar, or Winstrol to stack non-aromatising agents. Some protocols include it as a primary anabolic alongside a low testosterone base for a lean muscle preservation approach.