Ghrelin vs GHRP-2
A neutral, side-by-side comparison of two performance & growth hormone peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
Ghrelin
Endogenous 28-amino acid peptide secreted primarily by the stomach that functions as both the primary hunger signal and a potent growth hormone secretagogue. The n-octanoyl modification at Ser-3 (acylated form) is required for GHS-R1a receptor binding and GH-stimulating activity. Understanding ghrelin explains the mechanism behind the entire GHRP class of research peptides.
Full profileGHRP-2
GHRP-2 is a synthetic hexapeptide that acts as a ghrelin mimetic, stimulating the pituitary gland to secrete growth hormone (GH). It is one of the most potent GH secretagogues studied, producing stronger GH pulses than GHRP-6 with comparatively less appetite stimulation.
Full profile| Ghrelin | GHRP-2 | |
|---|---|---|
| Category | Performance & Growth Hormone | Performance & Growth Hormone |
| Also known as | GHRL, growth hormone-releasing peptide endogenous, ghrelinergic peptide, acyl ghrelin | Growth Hormone Releasing Peptide-2, Pralmorelin, KP 102 |
| Evidence | Investigational (in trials) | Preclinical only |
| Dosing range | 0.5mcg/kg–2mcg/kg mcg/kg, IV or SC bolus; endogenous levels peak pre-meal | 100mcg–300mcg mcg, 1–3 times daily, on an empty stomach |
| Administration | Intravenous (research), Subcutaneous injection | Subcutaneous injection, Intramuscular injection |
| Key side effects | Appetite stimulation, Transient hyperglycemia, Water retention, GH pulse stimulation | Increased hunger (less than GHRP-6), Elevated cortisol and prolactin at high doses, Water retention, Injection site irritation |
| Cited sources | 2 references | 3 references |
Key differences
- Evidence level differs: Ghrelin is investigational (in trials), while GHRP-2 is preclinical only.
- Administration: Ghrelin — Intravenous (research), Subcutaneous injection; GHRP-2 — Subcutaneous injection, Intramuscular injection.
- Dosing units differ: Ghrelin is dosed in mcg/kg, GHRP-2 in mcg — they operate at different scales.
- Frequency: Ghrelin is typically IV or SC bolus; endogenous levels peak pre-meal; GHRP-2 is 1–3 times daily, on an empty stomach.
- Research depth: this profile cites 2 sources for Ghrelin vs 3 for GHRP-2.
How each works
Ghrelin
Ghrelin was discovered in 1999 as the endogenous ligand for the GHS-R1a receptor. Its acylated form activates GH release from the pituitary, stimulates appetite via NPY/AgRP hypothalamic neurons, and modulates energy homeostasis and fat storage. The des-acyl form (majority of circulating ghrelin) lacks GHS-R1a activity but has independent cardiovascular and cellular effects.
GHRP-2
GHRP-2 has been extensively studied in both animal and human subjects. Clinical trials have demonstrated significant GH elevation in healthy adults, with a peak GH pulse occurring 15–30 minutes post-injection. Studies show it increases IGF-1 levels with chronic use and may have mild cardioprotective properties. Unlike GHRP-6, it has a lower propensity to stimulate cortisol and prolactin at standard doses.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.