P21 vs HGH Fragment 176-191
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 →HGH Fragment 176-191
HGH Fragment 176-191 is the fat-reducing portion of the growth hormone molecule. Unlike AOD-9604 (which has an additional tyrosine), this is the exact fragment of HGH responsible for lipolytic effects.
Full details →Side-by-Side Comparison
| Aspect | P21 | HGH Fragment 176-191 |
|---|---|---|
| Mechanism | Inhibits glycogen synthase kinase-3β (GSK-3β) and activates CREB signaling pathway. This promotes BDNF expression, neurogenesis in the hippocampus, and synaptic plasticity. | Mimics the lipolytic region of growth hormone, stimulating fat breakdown and inhibiting lipogenesis without affecting blood sugar or promoting growth. Works independently of GH receptors. |
| Typical Dosage | Research protocols typically use 1-5mg administered intranasally or subcutaneously. Often used in cycles of 2-4 weeks. | Typical dosing: 250-500mcg daily, often split into 2-3 doses. Usually administered on empty stomach, often with fasted cardio. |
| Administration | Can be administered intranasally for direct CNS access or subcutaneously. Best used cyclically rather than continuously. | Subcutaneous injection. Best results when used fasted and combined with exercise. Avoid eating for 30 minutes post-injection. |
| Side Effects | Limited data. Reported effects include mild headache, temporary brain fog during initial use, and fatigue. | Generally well-tolerated. May cause injection site irritation, temporary lethargy, or headache. Does not affect blood glucose significantly. |
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