Primobolan vs Semax
Well Studied vs Well Studied
monitor Mechanism-based · 51% Both Primobolan and Semax can raise blood pressure. Monitor BP regularly and consider adding cardiovascular support (cardarine, telmisartan, or similar).
Molecular Data
Primobolan Semax
Weight 302.45 Da (base) 813.93 Da
Half-life ~10 days (enanthate) 0.5-2 hours
Chain — 7 amino acids
Type DHT-derivative steroid (C20H30O2) ACTH(4-10) synthetic analog
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
Semax
01 Rapid brain delivery via intranasal route
02 Rapidly increases BDNF levels
03 Extensive clinical research in Russia
04 Easy self-administration
05 Modulates dopamine and serotonin systems
06 Neuroprotective effects
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
Semax
300-600mcg per dose (up to 1000mcg for intensive use) / 1-2x daily (morning recommended for cognitive boost)
Research protocol 500-750mcg 1x daily
Intensive protocol 750-1000mcg 1-2x 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
Semax
Mild nasal discomfort (nasal route)
Possible nasal sensation upon administration
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
Pregnancy or breastfeeding
Known peptide allergies
Do not exceed 4-week continuous use without medical supervision
Research Evidence
Primobolan Semax
Status Well Studied Well Studied
References 4 studies 5 studies
Latest January 2017 2025
FDA Approved No No
This comparison is for educational and research purposes only. Consult a healthcare professional before use.