LGD-4033 vs Semax
Moderate Research vs Well Studied
monitor Mechanism-based · 51% Both LGD-4033 and Semax can raise blood pressure. Monitor BP regularly and consider adding cardiovascular support (cardarine, telmisartan, or similar).
Molecular Data
LGD-4033 Semax
Weight 338.25 Da 813.93 Da
Half-life ~24-36 hours 0.5-2 hours
Chain — 7 amino acids
Type Nonsteroidal selective androgen receptor modulator (C14H12F6N2O) ACTH(4-10) synthetic analog
Key Benefits
LGD-4033
01 Strongest SARM for lean muscle mass accrual, with clinical trial data supporting dose-dependent increases in lean body mass
02 Tissue-selective action with minimal stimulation of the prostate and other androgen-sensitive tissues
03 Clinical evidence of improved physical function (leg press strength, stair-climbing speed) in hip fracture patients
04 No aromatization to estrogen (no estrogen-related water retention or gynecomastia at the receptor level)
05 No conversion to DHT (reduced risk of androgenic hair loss and prostate stimulation compared to testosterone)
06 Convenient once-daily oral dosing due to 24-36 hour half-life
07 Phase 2 clinical data available, providing a stronger evidence base than most other SARMs
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
LGD-4033
5-10 mg/day / Once daily (oral)
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
LGD-4033
Testosterone suppression (dose-dependent; more suppressive than Ostarine at equivalent doses, occurs in most users by week 4-6)
Water retention (non-estrogenic mechanism, typically mild to moderate, contributes to scale weight increase)
HDL cholesterol reduction (dose-dependent lipid impact observed in clinical trials)
Headaches (most common in the first 1-2 weeks, usually transient)
Fatigue or lethargy (related to testosterone suppression, typically becomes noticeable mid-cycle)
Reduced libido (related to HPG axis suppression, severity varies by dose and individual)
Semax
Mild nasal discomfort (nasal route)
Possible nasal sensation upon administration
Contraindications
Pre-existing liver disease or elevated liver enzymes at baseline
Hormone-sensitive cancers (prostate cancer or other androgen-driven malignancies)
Pregnancy or potential pregnancy (teratogenic risk from androgen receptor agonism)
Breastfeeding
Age under 25 (incomplete endocrine system maturation and higher risk of HPG axis disruption)
Concurrent use of hepatotoxic medications without medical supervision
Known cardiovascular disease (insufficient long-term safety data for this population)
History of significant lipid abnormalities (LGD-4033 suppresses HDL)
Pregnancy or breastfeeding
Known peptide allergies
Do not exceed 4-week continuous use without medical supervision
Research Evidence
LGD-4033 Semax
Status Moderate Research Well Studied
References 5 studies 5 studies
Latest 2018 2025
FDA Approved No No
This comparison is for educational and research purposes only. Consult a healthcare professional before use.