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Molecular structurePubMed
injectableanabolic
Methenolone Enanthate
PrimobolanPrimoPrimobol
88
Anabolic Ratio
57
Androgenic Ratio
10d
Half-Life
One of the mildest and most tolerable anabolic steroids. No aromatization, very low androgenic effect. Mild suppression. Ideal for women or those sensitive to side effects. Weak mass builder alone — best combined.
Mechanism of Action
Does not aromatize. Does not 5α-reduce significantly. Mild AR binding. Notable for uniquely low hepatotoxicity despite oral availability. Immune-modulating effects documented in HIV patients.
Typical Dosing
200 mg
low / week
400 mg
moderate / week
800 mg
high / week
⚠ Warning Flags
- •Very expensive and heavily counterfeited
Effect Profile
Muscle Protein Synthesis4Low
Nitrogen Retention5Moderate
Strength Gains4Low
Red Blood Cell Production3Low
Fat Loss5Moderate
Glycogen Storage3Low
Recovery Speed5Moderate
Collagen Synthesis4Low
Side Effect Profile
Hormonal Suppression3Low
Estrogenic Effects1Minimal
Androgenic Effects3Low
Cardiovascular Strain3Low
Liver Stress2Minimal
Insulin Resistance1Minimal
Mood Changes2Minimal
Prostate Risk2Minimal
Research Studies
Methenolone in HIV wasting: effects on weight and lean body mass
Porro LJ, et al. · 1995
Methenolone (Primobolan) preserved lean mass in HIV wasting patients with minimal androgenic side effects, supporting its clinical use as a mild anabolic.