MK-677 (Ibutamoren) vs P21
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
MK-677 (Ibutamoren)
MK-677, also known as Ibutamoren, is an orally active growth hormone secretagogue. Unlike peptides, it can be taken orally and has a long half-life, providing 24-hour GH elevation.
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 | MK-677 (Ibutamoren) | P21 |
|---|---|---|
| Mechanism | Acts as a potent, selective agonist of the ghrelin receptor (GHS-R1a). Increases GH and IGF-1 levels without affecting cortisol. Mimics ghrelin's GH-releasing effects. | 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: 10-25mg taken orally once daily. Often taken at night due to sleep benefits and appetite increase. | Research protocols typically use 1-5mg administered intranasally or subcutaneously. Often used in cycles of 2-4 weeks. |
| Administration | Oral administration (capsule or liquid). Can be taken with or without food. Long half-life allows once-daily dosing. | Can be administered intranasally for direct CNS access or subcutaneously. Best used cyclically rather than continuously. |
| Side Effects | Increased appetite and water retention are most common. May cause lethargy, vivid dreams, and mild numbness. Can affect blood glucose and insulin sensitivity. | Limited data. Reported effects include mild headache, temporary brain fog during initial use, and fatigue. |
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