Pentapeptide-18 vs P21
Side-by-side comparison of key properties, dosing, and research.
Skin & CosmeticAnti-Aging & Longevity
Pentapeptide-18Cognitive EnhancementAnti-Aging & Longevity
P21- 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.
- P21 is a synthetic peptide derived from CNTF (ciliary neurotrophic factor) that promotes hippocampal neurogenesis, enhances memory and spatial learning, and may reduce amyloid-beta pathology. It is used as a neurogenic and cognitive enhancer with potential anti-Alzheimer's applications.
- Half-Life
- Not applicable (topical)
- Not well characterized; likely short, but neurogenic effects persist long after administration
- Admin Route
- Topical
- SubQ, Intranasal
- Research
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- Typical Dose
- 0.005–0.05% in formulation
- 100–500 mcg
- 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
- Promotes hippocampal neurogenesis
- Enhances spatial memory and learning
- Increases BDNF expression
- Reduces amyloid-beta plaque formation (animal models)
- Anti-tau pathology potential
- Cognitive enhancement without stimulant effects
- Potential therapeutic for Alzheimer's and cognitive aging
- 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)
- Generally well tolerated in animal studies
- Limited human clinical data
- Injection site reactions
- Potential mild fatigue at initiation
- Stacks With
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