GHRP-2 vs Ipamorelin
Two ghrelin-receptor secretagogues separated by selectivity. GHRP-2 pulls cortisol, prolactin and appetite along with the GH pulse; ipamorelin was engineered to leave those alone.
Short answer
GHRP-2 and ipamorelin both have human clinical data, so the deciding factor is what you want them for. GHRP-2 suits someone focused on muscle, while ipamorelin is aimed at muscle and fat loss. For GHRP-2, five days of daily injections in healthy men did not raise IGF-1, and the GH response faded.
GHRP-2
Pralmorelin
Genuinely raises GH (and is an approved diagnostic in Japan), but the same dose lifts cortisol, prolactin and appetite, and desensitizes — no anti-aging outcomes.
Full GHRP-2 evidence reviewIpamorelin
Raises GH, but failed its one rigorous human efficacy RCT; no body-composition outcome data.
Full Ipamorelin evidence reviewGHRP-2 vs Ipamorelin: head to head
- FDA status / approved use
GHRP-2
Approved in Japan only as a growth-hormone diagnostic; not FDA-approved; sold as gray-market research peptideIpamorelin
Not approved for its marketed uses; sold as unregulated research-use-only products- Marketed for
GHRP-2
Muscle, 'anti-aging'Ipamorelin
Muscle, fat loss, 'anti-aging'- Outcome areas
GHRP-2
Muscle / strength / lean mass; Longevity / lifespanIpamorelin
Muscle / strength / lean mass; Weight loss / appetite; Longevity / lifespan- Evidence grade
GHRP-2
Clinical dataIpamorelin
Clinical data- How it works
GHRP-2
Activates the ghrelin receptor to trigger a pulse of growth hormone from the pituitaryIpamorelin
Selective ghrelin mimetic that triggers a growth hormone pulse- Route and dosing
GHRP-2
Subcutaneous injectionIpamorelin
Injection, usually sold together with CJC-1295- Headline human result
GHRP-2
Five days of daily injections in healthy men did not raise IGF-1, and the GH response fadedIpamorelin
Failed its primary endpoint in a randomized trial for bowel recovery after surgery; no muscle or fat-loss outcome trials- Strongest evidence
GHRP-2
Bowers, Endocrine 2001GHRP-2 evidence reviewPubMed 11322505Ipamorelin
Beck RCT, 2014Ipamorelin evidence reviewPubMed 25331030- Key safety signal
GHRP-2
Also raises cortisol, ACTH and prolactin and increases appetiteIpamorelin
Unverified dose, purity and identity; chronic GH/IGF-1 stimulation raises unaddressed safety concerns- How it is obtained
GHRP-2
Sold gray-market as a research chemical; no approved or legitimately compounded human productIpamorelin
Sold gray-market as a research chemical; no approved or legitimately compounded human product
| GHRP-2 | Ipamorelin | |
|---|---|---|
| FDA status / approved use | Approved in Japan only as a growth-hormone diagnostic; not FDA-approved; sold as gray-market research peptide | Not approved for its marketed uses; sold as unregulated research-use-only products |
| Marketed for | Muscle, 'anti-aging' | Muscle, fat loss, 'anti-aging' |
| Outcome areas | Muscle / strength / lean mass; Longevity / lifespan | Muscle / strength / lean mass; Weight loss / appetite; Longevity / lifespan |
| Evidence grade | Clinical data | Clinical data |
| How it works | Activates the ghrelin receptor to trigger a pulse of growth hormone from the pituitary | Selective ghrelin mimetic that triggers a growth hormone pulse |
| Route and dosing | Subcutaneous injection | Injection, usually sold together with CJC-1295 |
| Headline human result | Five days of daily injections in healthy men did not raise IGF-1, and the GH response faded | Failed its primary endpoint in a randomized trial for bowel recovery after surgery; no muscle or fat-loss outcome trials |
| Strongest evidence | Bowers, Endocrine 2001GHRP-2 evidence reviewPubMed 11322505 | Beck RCT, 2014Ipamorelin evidence reviewPubMed 25331030 |
| Key safety signal | Also raises cortisol, ACTH and prolactin and increases appetite | Unverified dose, purity and identity; chronic GH/IGF-1 stimulation raises unaddressed safety concerns |
| How it is obtained | Sold gray-market as a research chemical; no approved or legitimately compounded human product | Sold gray-market as a research chemical; no approved or legitimately compounded human product |
marks a row where the two differ. “Not established” marks a cell the available evidence does not answer. Evidence grades come from our evidence matrix, which grades each molecule on the human data for the use it is marketed for.
- Clinical data:
- Tested in humans — but investigational, discontinued, or proven only on a surrogate marker (not the marketed outcome).
Our verdict
GHRP-2 has the deeper human pharmacology; it reliably raises GH and is an approved GH-stimulation diagnostic in Japan. But the same dose raises ACTH, cortisol and prolactin, increases food intake, and in healthy young men five days of daily dosing attenuated the GH response without raising IGF-1. Ipamorelin is the selective alternative on paper, with little effect on cortisol or prolactin, but its one rigorous human efficacy trial, for recovery of bowel function after surgery, failed its primary endpoint and the program did not advance. Neither is approved for body composition or anti-aging; both are sold research-only, and they have not been compared head to head.
GHRP-2 fits if
GHRP-2 is the better-characterized molecule for anyone whose interest is GH secretion itself, since it has a validated stimulation-test literature behind it.
Ipamorelin fits if
Ipamorelin is the one to read about if selectivity is the question, since it is the agent designed to raise GH with minimal cortisol, prolactin or appetite spillover.
GHRP-2 vs Ipamorelin: common questions
- Is either GHRP-2 or ipamorelin FDA-approved?
- No. GHRP-2 is approved in Japan only as a growth-hormone diagnostic; not FDA-approved; sold as gray-market research peptide. Ipamorelin is not approved for its marketed uses; sold as unregulated research-use-only products.
- Which has stronger human evidence, GHRP-2 or ipamorelin?
- Neither clearly. Both have human clinical data. The key source for GHRP-2 is Bowers, Endocrine 2001; for ipamorelin, it is Beck RCT, 2014.
- What are the main safety concerns with GHRP-2 and ipamorelin?
- GHRP-2 also raises cortisol, ACTH and prolactin and increases appetite. For ipamorelin, watch for unverified dose, purity and identity; chronic GH/IGF-1 stimulation raises unaddressed safety concerns.
Key studies behind each
GHRP-2
- Arvat E, di Vito L, Maccagno B, Broglio F, Boghen MF, Deghenghi R, Camanni F, Ghigo E. (1997). Effects of GHRP-2 and hexarelin, two synthetic GH-releasing peptides, on GH, prolactin, ACTH and cortisol levels in man. Comparison with the effects of GHRH, TRH and hCRH. Peptides. PubMed 9285939
- Bowers CY, Granda-Ayala R. (2001). Growth hormone/insulin-like growth factor-1 response to acute and chronic growth hormone-releasing peptide-2, growth hormone-releasing hormone 1-44NH2 and in combination in older men and women with decreased growth hormone secretion. Endocrine. PubMed 11322505
- Chihara K, Shimatsu A, Hizuka N, Tanaka T, Seino Y, Katofor Y; KP-102 Study Group. (2007). A simple diagnostic test using GH-releasing peptide-2 in adult GH deficiency. Eur J Endocrinol. PubMed 17609397
- Laferrère B, Abraham C, Russell CD, Bowers CY. (2005). Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. J Clin Endocrinol Metab. PubMed 15699539
Ipamorelin
- Raun K, Hansen BS, Johansen NL, et al. (1998). Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. PubMed 9849822
- Teichman SL, Neale A, Lawrence B, et al. (2006). Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab. PubMed 16352683
- Venkova K, Mann W, Nelson R, Greenwood-Van Meerveld B. (2009). Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus. J Pharmacol Exp Ther. PubMed 19289567
- Beck DE, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group. (2014). Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Int J Colorectal Dis. PubMed 25331030
The full evidence reviews
- GHRP-2: a real GH secretagogue, marketed for things it hasn't been shown to do
GHRP-2 (pralmorelin) genuinely raises growth hormone and is an approved diagnostic agent in Japan — but the same dose lifts cortisol, ACTH and prolactin, drives appetite, and desensitizes with daily use. A straight read of the human data behind the anti-aging marketing.
Updated August 2026
- Ipamorelin & CJC-1295: the honest evidence on GH secretagogue peptides
They reliably raise growth hormone, and that part is real. The muscle, fat-loss and anti-aging claims are not supported by human outcome data. A straight read.
Updated October 2026
Where to get it
Where to get peptide therapy
Clinician-led telehealth services that prescribe compounded peptides. The specific peptides offered vary by provider — confirm GHRP-2 availability before ordering.
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