Hexarelin vs P21
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
Hexarelin
Hexarelin is a potent synthetic hexapeptide growth hormone secretagogue. It provides the strongest GH release among GHRPs but is associated with rapid desensitization of receptors.
Full details →P21
P21 is a synthetic peptide derived from Cerebrolysin, specifically designed to mimic the neurotrophic effects of the parent compound. It promotes neurogenesis and has shown cognitive-enhancing properties in research.
Full details →Side-by-Side Comparison
| Aspect | Hexarelin | P21 |
|---|---|---|
| Mechanism | Acts as a ghrelin mimetic with high potency at the GHS receptor. Provides powerful GH release but receptor desensitization occurs faster than with other GHRPs, requiring cycling. | Inhibits glycogen synthase kinase-3β (GSK-3β) and activates CREB signaling pathway. This promotes BDNF expression, neurogenesis in the hippocampus, and synaptic plasticity. |
| Typical Dosage | Typical dosing: 100-200mcg administered 2-3 times daily for 4-6 weeks, followed by an equal off period to allow receptor resensitization. | Research protocols typically use 1-5mg administered intranasally or subcutaneously. Often used in cycles of 2-4 weeks. |
| Administration | Subcutaneous injection. Cycling is essential to maintain effectiveness. Often used in short bursts rather than continuous protocols. | Can be administered intranasally for direct CNS access or subcutaneously. Best used cyclically rather than continuously. |
| Side Effects | Water retention, cortisol and prolactin increase, hunger (moderate), tingling, and potential blood pressure effects. | Limited data. Reported effects include mild headache, temporary brain fog during initial use, and fatigue. |
| Best For |