GHRP-2 vs P21
Side-by-side comparison of key properties, dosing, and research.
- Summary
- GHRP-2 is a potent synthetic hexapeptide that stimulates growth hormone release by activating ghrelin receptors in the pituitary and hypothalamus. It produces one of the strongest GH pulses among GHRPs, though unlike Ipamorelin it does cause modest increases in cortisol and prolactin.
- 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
- 15–60 minutes
- Not well characterized; likely short, but neurogenic effects persist long after administration
- Admin Route
- SubQ, Intranasal
- SubQ, Intranasal
- Research
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- Typical Dose
- 100–300 mcg
- 100–500 mcg
- Frequency
- 2–3 times daily
- Once daily
- Key Benefits
- Strong GH pulse stimulation
- Increased IGF-1 levels
- Enhanced muscle growth and recovery
- Improved fat metabolism
- Better sleep quality
- Increased bone density
- Enhanced appetite (less pronounced than GHRP-6)
- Anti-aging effects via GH axis optimization
- 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
- Increased appetite
- Water retention
- Elevated cortisol (modest)
- Elevated prolactin (modest)
- +2 more
- Generally well tolerated in animal studies
- Limited human clinical data
- Injection site reactions
- Potential mild fatigue at initiation
- Stacks With
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