Pentapeptide-18 vs Somatropin (HGH)
Side-by-side comparison of key properties, dosing, and research.
Skin & CosmeticAnti-Aging & Longevity
Pentapeptide-18Growth Hormone PeptidesAnti-Aging & Longevity
Somatropin (HGH)- Summary
- Pentapeptide-18 (Leuphasyl) is a synthetic pentapeptide that mimics the sequence of enkephalin, an endogenous neuropeptide. It acts on neuronal pain receptors in facial muscles to reduce muscle contraction intensity and depth of expression lines, functioning similarly to Argireline (Acetyl Hexapeptide-3) but via a different receptor mechanism.
- Somatropin is recombinant human growth hormone (rhGH), identical in structure to the 191-amino acid pituitary-derived growth hormone. It is FDA-approved for growth hormone deficiency, short stature, and wasting conditions. Off-label, it is widely explored for body composition, anti-aging, and performance enhancement, though significant risks accompany unsupervised use.
- Half-Life
- Not applicable (topical)
- 2-3 hours (subcutaneous); 20-30 minutes (intravenous)
- Admin Route
- Topical
- Subcutaneous, Intramuscular (less common)
- Research
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- Typical Dose
- 0.005–0.05% in formulation
- 0.15-0.3 mg/day (adults); titrated to IGF-1 levels
- Frequency
- Twice daily
- Once daily
- Key Benefits
- Reduces depth of expression lines (forehead, crow's feet, glabellar)
- Inhibits acetylcholine release for muscle-relaxing effect
- Complementary mechanism to Argireline for enhanced anti-wrinkle activity
- Reversible and well-tolerated
- No risk of systemic paralysis at cosmetic concentrations
- Suitable for daily use in serums and creams
- Increases lean muscle mass and reduces body fat (particularly visceral)
- Restores growth hormone deficiency (FDA-approved)
- Improves bone mineral density
- Enhances exercise capacity and recovery
- Supports skin thickness and collagen synthesis
- Improves lipid profile in GHD patients
- Explored for anti-aging and cellular regeneration
- Side Effects
- Generally very well-tolerated topically
- Rare skin sensitivity or mild irritation
- Theoretical opioid receptor desensitization with very prolonged high-dose use (not documented cosmetically)
- Fluid retention and edema (common, dose-dependent)
- Carpal tunnel syndrome
- Joint and muscle pain
- Insulin resistance and elevated blood glucose
- +3 more
- Stacks With
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