Two classic growth-hormone-releasing peptides, compared.
| Attribute | GHRP-2 Research use only | GHRP-6 Research use only |
|---|---|---|
| Class / type | GH secretagogue / ghrelin mimetic (hexapeptide) | GH secretagogue / ghrelin mimetic (the original GHRP) |
| How it works | Agonist at GHS-R1a on pituitary and hypothalamic neurons; strong GH release with comparatively less appetite, cortisol and prolactin than GHRP-6. | Non-selective GHS-R1a agonist; besides GH release it activates hypothalamic NPY/AgRP feeding neurons (intense hunger) and raises cortisol/prolactin. |
| Known / used for | No approved use; off-label/research for GH stimulation, body composition, recovery; studied as a GH-secretion diagnostic. | No approved use; off-label/research for GH stimulation and appetite stimulation. |
| Positives | High peak GH release; less appetite stimulation than GHRP-6; short-acting pulse. | Robust GH release; pronounced appetite boost can help hard-gainers/bulking; short-acting. |
| Negatives & risks | Can still raise cortisol/prolactin (dose-dependent); water retention/bloating, fatigue, injection-site reactions; no long-term human data; purity concerns. | Intense hunger; greater cortisol/prolactin rise (gynecomastia risk in sensitive users); water retention, bloating, fatigue, injection-site reactions; no long-term data; purity concerns. |
| Legal status (Jul 2026) | NOT FDA-approved; research-use-only; not compounding-approved. WADA-banned. | NOT FDA-approved; research-use-only; not compounding-approved. WADA-banned. |