Hexarelin vs P21
Side-by-side comparison of key properties, dosing, and research.
- Summary
- Hexarelin is a potent synthetic GHRP and the strongest GH secretagogue in its class per unit dose. It also exhibits unique cardioprotective properties through direct binding to cardiac CD36 receptors, independent of GH release. Its potency is balanced by a tendency to desensitize GH release with prolonged use, making cycling important.
- 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
- ~70 minutes
- Not well characterized; likely short, but neurogenic effects persist long after administration
- Admin Route
- SubQ
- SubQ, Intranasal
- Research
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- Typical Dose
- 100–200 mcg
- 100–500 mcg
- Frequency
- 2–3 times daily
- Once daily
- Key Benefits
- Strongest GH pulse per mcg among GHRPs
- Unique direct cardioprotective effects via CD36
- Increased IGF-1 and muscle anabolism
- Accelerated recovery from training
- Bone density support
- Anti-aging via GH axis
- Potential cardiac rehabilitation 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
- Side Effects
- Water retention
- Elevated cortisol
- Elevated prolactin (more pronounced than other GHRPs)
- Receptor desensitization with continuous use
- +1 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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