Primobolan vs Tamoxifen
Well Studied vs FDA Approved
avoid Mechanism-based · 64% Both Primobolan and Tamoxifen carry hepatotoxic risk. Combining hepatotoxic compounds significantly increases liver damage potential. If unavoidable, include liver support (TUDCA/NAC) and monitor ALT/AST frequently.
Molecular Data
Primobolan Tamoxifen
Weight 302.45 Da (base) 371.51 Da
Half-life ~10 days (enanthate) ~5-7 days
Type DHT-derivative steroid (C20H30O2) Triphenylethylene-derived selective estrogen receptor modulator
Key Benefits
Primobolan
01 Lean muscle mass preservation during caloric deficits with minimal water retention
02 Does not aromatize to estrogen, eliminating estrogen-related side effects
03 One of the mildest androgenic profiles among anabolic steroids, with reduced risk of acne, aggression, and prostate issues
04 Injectable form is non-hepatotoxic, allowing extended cycle durations
05 Strong anti-catabolic properties through glucocorticoid receptor modulation
06 Immune-enhancing effects at moderate therapeutic doses
07 Quality, keepable muscle gains without the bloated appearance common with aromatizing steroids
08 Compatible with long cycle lengths (16-20 weeks) due to mild overall impact on health markers
Tamoxifen
01 Blocks estrogen receptor signaling in breast tissue, preventing and treating gynecomastia
02 Stimulates LH and FSH production by antagonizing hypothalamic estrogen receptors
03 Restores endogenous testosterone production during post-cycle therapy
04 Partial estrogen agonist activity in bone preserves bone mineral density
05 Extremely long half-life allows for flexible dosing schedules
06 Decades of clinical use with a well-characterized safety and efficacy profile
07 Oral administration with no injections or reconstitution required
Dosing Protocols
Primobolan
400-800 mg/week (injectable) or 50-100 mg/day (oral) / 1-2x per week (enanthate) or daily (oral acetate)
Lean Mass Preservation - Cutting 400-600 mg/week 2x per week (split dose)
Lean Bulking 600-800 mg/week 2x per week (split dose)
Female Protocol 50-100 mg/week 1x per week
Tamoxifen
20-40mg oral daily / Once daily
Side Effects
Primobolan
Suppression of natural testosterone production (dose-dependent, less suppressive than many other anabolic steroids but still significant)
Hair thinning or accelerated male pattern baldness (DHT derivative -- this is the most commonly reported side effect in susceptible individuals)
Adverse lipid changes, particularly HDL suppression (moderate compared to other anabolic steroids)
Mild acne or oily skin (less pronounced than testosterone or other androgens)
Injection site discomfort from larger oil volumes required at performance doses
Gradual decline in natural testosterone production requiring post-cycle therapy
Tamoxifen
Hot flashes and night sweats
Nausea or gastrointestinal discomfort
Mood swings, irritability, or emotional lability
Fatigue during initial weeks of use
Headache
Contraindications
Prostate cancer (active or history of hormone-sensitive prostate cancer)
Breast cancer in males or females
Pregnancy or potential for pregnancy (teratogenic risk -- fetal virilization)
Severe hepatic impairment (particularly relevant for oral acetate form)
Known hypersensitivity to metenolone or formulation components
Hypercalcemia
Polycythemia (hematocrit above 54% at baseline)
Uncontrolled cardiovascular disease or severe dyslipidemia
History of deep vein thrombosis, pulmonary embolism, or other thromboembolic events
Known hypersensitivity to tamoxifen citrate or any excipients
Concurrent warfarin or coumarin-type anticoagulant therapy (increased bleeding risk)
Pregnancy or planned pregnancy (category D -- known teratogenic risk)
Pre-existing endometrial hyperplasia or uterine cancer
Severe hepatic impairment
Research Evidence
Primobolan Tamoxifen
Status Well Studied FDA Approved
References 4 studies 5 studies
Latest January 2017 —
FDA Approved No Yes
This comparison is for educational and research purposes only. Consult a healthcare professional before use.