Primobolan (Methenolone Enanthate) — Dosing, Cycles, Half-Life & Side Effects
Primobolan (Methenolone Enanthate) is a DHT-derived anabolic-androgenic steroid with a half-life of ~10.5 days. Mild injectable DHT derivative known for lean tissue preservation with an excellent safety profile. Non-17α-alkylated, no aromatization. One of the safest anabolic steroids available, commonly counterfeited due to high demand. This page is educational harm-reduction reference compiled from peer-reviewed literature — not medical advice, not an endorsement, not a recommendation to use. Consult a licensed clinician before any decision.
Quick Facts
| Class | DHT Derivatives |
|---|---|
| Half-life | ~10.5 days |
| Detection window | 45 days |
| Aromatization | No |
| Hepatotoxicity | None |
| Suppression | 5/10 |
| 17α-alkylated | No |
| Administration | injectable |
Typical Dosing Ranges
Common dose range: 300-800mg/week (males), 50-100mg/week (females)
Cycle length: 10-16 weeks
Time to steady state: ~53 days
Dose ranges are compiled from published pharmacokinetic studies and community-reported usage. Where a value is community-reported rather than clinically studied, this page and its structured data flag it. Lower end of any range is always the safer starting point.
Stacking Considerations
- No structural stacking blockers. Standard harm-reduction rules apply: minimize total androgen load, minimize oral exposure, and monitor bloodwork.
PCT Requirements
- This compound causes clinically meaningful HPTA suppression. Post-cycle therapy is recommended.
- Depot clearance estimate: ~53 days post-last-dose before SERM start (5 × apparent depot half-life of 252h).
- Never stack two SERMs. Extend a single SERM (tamoxifen OR enclomiphene/clomiphene) rather than combining.
- Use the cycle planner to generate a full protocol based on your complete stack, not this compound alone.
Side Effect Profile
- Very expensive
- Commonly counterfeited
- Mild anabolic effects - high doses needed
- Hair loss risk (DHT derivative)
- Significant HDL suppression
Known Interactions
Testosterone Cypionate + Primobolan (Methenolone Enanthate)
minor — synergisticGood synergy with low sides. Common stack.
Recommendation: Generally well-tolerated combination.
Monitor: Standard bloodwork
Related compounds
Anadrol (Oxymetholone)
Orals · t½ 8-9 hours
Anavar (Oxandrolone)
Orals · t½ 8-9 hours
Deca Durabolin (Nandrolone Decanoate)
19-nor · t½ 6-12 days (apparent depot terminal half-life; free nandrolone elimination ~4.3h after de-esterification; Minto CF et al. 1997 PMID 9103484)
Dianabol (Methandrostenolone)
Orals · t½ 3-6 hours
Monitoring (Bloodwork & Vitals)
- Comprehensive metabolic panel (baseline, mid-cycle, post-cycle)
- Lipid panel (total cholesterol, HDL, LDL, triglycerides)
- CBC (hemoglobin, hematocrit — watch for erythrocytosis)
- Sex-hormone panel (Total T, Free T, Estradiol sensitive, SHBG, LH, FSH)
- Blood pressure (weekly self-check; flag systolic >140 or diastolic >90)
Baseline bloodwork is recommended before any cycle. Discontinue if liver enzymes exceed 3× upper limit of normal or if hematocrit exceeds 54%.
Frequently Asked Questions
What is the half-life of Primobolan (Methenolone Enanthate)?
Primobolan (Methenolone Enanthate) has a half-life of approximately ~10.5 days. Clearance estimate: 252h × 5 = 1260h = 52.5 days. This figure is used to determine injection frequency (for esters) and post-cycle clearance timing.
What is the typical dose range for Primobolan (Methenolone Enanthate)?
Commonly reported ranges for Primobolan (Methenolone Enanthate): 300-800mg/week (males), 50-100mg/week (females). Cycle length: 10-16 weeks. These are compiled from published studies and community-reported usage — individual response varies and lower end is always preferred.
Does Primobolan (Methenolone Enanthate) suppress natural testosterone?
Primobolan (Methenolone Enanthate) causes moderate suppression of the HPTA axis (score 5/10). Post-cycle therapy (PCT) is recommended after use.
Does Primobolan (Methenolone Enanthate) aromatize to estrogen?
Aromatization profile: No. Minimal to no aromatization expected, so aromatase inhibitors are not typically indicated for this compound alone.
What is Primobolan (Methenolone Enanthate) typically used for?
Primobolan (Methenolone Enanthate) is commonly used for: Cutting, Lean bulking, Female cycles, Intermediate to advanced users. Intended-use context does not imply safety — every use case carries the same underlying pharmacological risks.
Citations
- Llewellyn W. 2011. ANABOLICS 11th ed (Tier-2 community-curated reference) — Methenolone enanthate t½ 10.5 days. NO PEER-REVIEWED PK STUDY EXISTS — Schering withdrew Primobolan Depot before modern PK methodology was applied. Llewellyn is the best available source. This figure is weaker-sourced than testosterone esters (Tier-1 PK studies) and should be interpreted with that caveat.
- Liu et al.. 2025. Substance Use & Misuse — AAS meta-analysis: SBP +12.43 mmHg (95% CI: 9.59-15.26), LDL-C +9.12 mg/dL (95% CI: 6.75-11.49)
- Hartgens F, Kuipers H. Effects of androgenic-anabolic steroids in athletes. Sports Med 2004
- Kicman AT. Pharmacology of anabolic steroids. Br J Pharmacol. 2008;154(3):502-21. PMID: 18500378
Disclaimer
StackItSmart is an independent harm-reduction reference. The content above is compiled from peer-reviewed literature and is not medical advice, not an endorsement, and not a recommendation to use Primobolan (Methenolone Enanthate). Performance-enhancing compounds carry legal, endocrine, cardiovascular, and hepatic risks. Consult a licensed clinician before any decision. StackItSmart does not provide sourcing, procurement, or dosing prescriptions.