P21 vs Mod GRF 1-29
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
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 →Mod GRF 1-29
Mod GRF 1-29 (Modified GRF 1-29, also called CJC-1295 without DAC or Tetrasubstituted GRF 1-29) is a modified growth hormone-releasing hormone analog with improved stability over natural GHRH.
Full details →Side-by-Side Comparison
| Aspect | P21 | Mod GRF 1-29 |
|---|---|---|
| Mechanism | Inhibits glycogen synthase kinase-3β (GSK-3β) and activates CREB signaling pathway. This promotes BDNF expression, neurogenesis in the hippocampus, and synaptic plasticity. | Binds to GHRH receptors in the pituitary gland to stimulate growth hormone release. Four amino acid substitutions improve resistance to enzymatic degradation while maintaining biological activity. |
| Typical Dosage | Research protocols typically use 1-5mg administered intranasally or subcutaneously. Often used in cycles of 2-4 weeks. | Typical dosing: 100-300mcg administered 2-3 times daily, usually combined with a GHRP like Ipamorelin for synergistic effects. |
| Administration | Can be administered intranasally for direct CNS access or subcutaneously. Best used cyclically rather than continuously. | Subcutaneous injection. Best administered on empty stomach. Short half-life (~30 minutes) necessitates multiple daily doses, unlike DAC version. |
| Side Effects | Limited data. Reported effects include mild headache, temporary brain fog during initial use, and fatigue. | Flushing, headache, dizziness, and injection site reactions. Generally well-tolerated. May cause water retention. |
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