P21 vs Pal-GHK
Side-by-side comparison of key properties, dosing, and research.
- Summary
- 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.
- Pal-GHK is the palmitoylated form of the GHK tripeptide without a copper ion. By conjugating palmitic acid to glycine-histidine-lysine, skin penetration is substantially enhanced, enabling deeper dermal collagen stimulation. It is commonly paired with Pal-GHK-Cu or GHK-Cu in anti-aging formulations.
- Half-Life
- Not well characterized; likely short, but neurogenic effects persist long after administration
- Extended (lipid depot in stratum corneum)
- Admin Route
- SubQ, Intranasal
- Topical
- Research
- —
- —
- Typical Dose
- 100–500 mcg
- 0.005–0.1% in formulation
- Frequency
- Once daily
- Once or twice daily
- Key Benefits
- 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
- Stimulates collagen I and III synthesis in dermis
- Reduces the appearance of fine lines and wrinkles
- Improves skin elasticity and firmness
- Inhibits collagenase (MMP-1) to preserve existing collagen
- Enhances wound healing and skin repair
- Well-tolerated in anti-aging serums and creams
- Side Effects
- Generally well tolerated in animal studies
- Limited human clinical data
- Injection site reactions
- Potential mild fatigue at initiation
- Generally very well-tolerated
- Rare skin irritation at very high concentrations
- Possible formulation-dependent comedogenicity
- Stacks With
- —
- —