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Compound comparison
Ipamorelin set against tesamorelin, CJC-1295, sermorelin, GHRP-2, GHRP-6 and MK-677 on target, mechanism, human evidence and regulatory status.
By the Ipamorelin Research editorial team · Last reviewed · Scientific review: pending
Short answer
The compounds ipamorelin is compared with fall into two groups that act at two different receptors. GHRP-2, GHRP-6 and MK-677 act at GHSR-1a, the same receptor as ipamorelin. Sermorelin, CJC-1295 and tesamorelin are GHRH analogues acting at the GHRH receptor. Only one of the seven, tesamorelin, is an approved drug.
Select up to three compounds to set against ipamorelin. Chemistry comes from PubChem and approval status from FDA Drugs@FDA; fields that could not be verified from a primary source say so rather than being filled in.
| Field | Ipamorelin(this site) | Tesamorelin | CJC-1295 |
|---|---|---|---|
| Classification | Synthetic pentapeptide growth hormone secretagogue | Synthetic GHRH analogue (stabilised GHRH 1-44) | GHRH analogue, supplied with or without a drug affinity complex |
| Receptor target | GHSR-1a | GHRH receptor | GHRH receptor |
| Mechanism | Agonist at the growth hormone secretagogue receptor GHSR-1a, the receptor for endogenous ghrelin. Antagonist profiling showed it acts through a GHRP-like receptor and not the GHRH receptor. | Binds the growth hormone-releasing hormone receptor on pituitary somatotrophs, a different receptor from the one ipamorelin acts on. The two compounds reach GH release by separate routes. | A GHRH (1-29) analogue acting at the GHRH receptor. The version with a drug affinity complex binds albumin to extend circulation time. Because it acts at a different receptor from ipamorelin, the two are often marketed as complementary; no controlled human trial of the combination is indexed in this database. |
| Molecular formula | C38H49N9O5 | C221H366N72O67S | C165H269N47O46 |
| Molecular weight | 711.9 | 5136 | 3647.2 |
| Size | 5 residues, C-terminal amide; three non-standard residues | 44 residues, roughly seven times the mass of ipamorelin | 29-residue analogue, about five times the mass of ipamorelin |
| Research history | Described in 1998 at Novo Nordisk. Preclinical work through the 2000s covered GH release, bone, body composition and metabolism. A clinical programme in postoperative ileus ran from 2008 to 2014. | Developed as a GHRH analogue and taken through a full clinical development programme, including phase 3 trials in HIV-associated lipodystrophy. | A glycine-extended analogue of modified GRF (1-29) was among the compounds identified in material seized by Danish customs authorities in 2019. |
| Human clinical evidence | One randomised controlled trial (n = 117) in postoperative ileus, published in 2014, which found no significant difference from placebo on its efficacy endpoints. One 1999 dose-escalation pharmacodynamic study in 40 healthy men. One single-subject intranasal excretion study. A larger phase 2 dose-finding trial (n = 320) completed in 2014 and has never been reported. | Phase 3 randomised controlled trials supporting an approved indication. This is a categorically larger and more rigorous human evidence base than exists for ipamorelin. | No randomised controlled human trial of CJC-1295 is indexed in this database, which searches for ipamorelin rather than CJC-1295. No controlled human trial of CJC-1295 combined with ipamorelin is indexed here. |
| Regulatory status | Not an approved drug in the United States. FDA placed ipamorelin acetate in Category 2 for 503B compounding in September 2023, and in October 2024 an advisory committee voted 12 to 0 against adding either form to the 503A Bulks List. | Approved by FDA. A Drugs@FDA query returns BLA 022505 with the brand names EGRIFTA SV and EGRIFTA WR, marketing status prescription. | Not an approved drug. A Drugs@FDA query returns no match. |
| Known safety concerns | FDA cited immunogenicity risk from aggregation or peptide-related impurities, complexity of characterisation from unnatural amino acids, and serious adverse events including two deaths in the published trial, while stating it is unclear whether those deaths were related to ipamorelin. | Has FDA-approved labelling, which carries the full approved safety information. That labelling, not this site, is the reference for its risks. | This database holds no primary safety study of CJC-1295. The product-identity findings for seized material apply to this compound as well as to ipamorelin. |
| Evidence gaps | No human study has measured body composition, muscle mass or strength, athletic recovery, sleep or any ageing endpoint. No human IGF-1 measurement is indexed. Long-term human safety data do not exist. | Approval covers a specific indication and population. Its approval says nothing about ipamorelin, and does not transfer to it. | The pairing of a GHRH analogue with a ghrelin-receptor agonist is a pharmacological rationale, not a demonstrated outcome. The search volume for the combination is very large; the controlled human evidence for it is absent. |
| Half-life | About 2 hoursHealthy human males, intravenous infusion (PMID 10496658) | Not verified for this siteNot retrieved from a primary source | Not verified for this siteNot retrieved from a primary source |
Chemistry was retrieved from PubChem and approval status checked against FDA Drugs@FDA. Fields reading “not verified for this site” were not confirmed from a primary source, and are left blank rather than filled from memory. This table makes no recommendation and describes no combination.
The distinction that matters most
Comparisons in this area usually get framed as potency or duration, but the first question is which receptor a compound acts on. Ipamorelin, GHRP-2, GHRP-6 and MK-677 act at GHSR-1a, the ghrelin receptor. Sermorelin, CJC-1295 and tesamorelin act at the GHRH receptor. Both routes end at growth hormone release, but they are separate systems, and that is why a GHRH analogue and a ghrelin-receptor agonist are often described as complementary rather than interchangeable. Ipamorelin's own receptor was established pharmacologically, with GHRP and GHRH antagonists showing it works through a GHRP-like receptor and not the GHRH receptor[Raun 1998].
Where ipamorelin genuinely differs
- From GHRP-2 and GHRP-6: the selectivity finding. In conscious swine, GHRP-6 and GHRP-2 raised ACTH and cortisol while ipamorelin did not, at doses more than 200-fold above its growth hormone ED50 [Raun 1998]. Separately, ipamorelin's plasma clearance in rats was five-fold lower than GHRP-6's, and it was excreted mainly in urine where GHRP-6 went predominantly to bile[Johansen 1998].
- From MK-677: route and persistence. MK-677 is not a peptide and is orally active; ipamorelin is an injectable peptide with a two-hour half-life. They share a receptor, and radiolabelled MK-677 is the ligand used in the binding assays that characterise this class [Hansen 1999].
- From tesamorelin: evidence base. Tesamorelin has an approved application and a phase 3 programme behind it [openFDA]. Ipamorelin has one published randomised trial, whose primary efficacy result was null.
Dedicated comparisons
Three comparisons have enough search demand and enough substantive difference to warrant their own page:
- Ipamorelin vs CJC-1295 — different receptors, and the pairing most often discussed.
- Ipamorelin vs tesamorelin — an unapproved compound against an approved one.
- Ipamorelin vs sermorelin — the GHSR-1a and GHRH receptor distinction at its clearest.
GHRP-2, GHRP-6 and MK-677 are covered in the tool above rather than on separate pages, because the searches for them are comparatively small and the substantive content is the receptor and route distinction already set out here.
References
- Raun K, Hansen BS, Johansen NL et al. (1998). Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. PubMed 9849822 · doi:10.1530/eje.0.1390552[Animal, grade C]
- Johansen PB, Hansen KT, Andersen JV et al. (1998). Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues with emphasis on nasal absorption. Xenobiotica. PubMed 9879640 · doi:10.1080/004982598238976[Animal, grade C]
- Ahnfelt-Rønne I, Nowak J, Olsen UB (2001). Do growth hormone-releasing peptides act as ghrelin secretagogues?. Endocrine. PubMed 11322495 · doi:10.1385/ENDO:14:1:133[Animal, grade C]
- Hansen BS, Raun K, Nielsen KK et al. (1999). Pharmacological characterisation of a new oral GH secretagogue, NN703. Eur J Endocrinol. PubMed 10427162 · doi:10.1530/eje.0.1410180[Animal, grade C]
- Gajda PM, Holm NB, Hoej LJ et al. (2019). Glycine-modified growth hormone secretagogues identified in seized doping material. Drug Test Anal. PubMed 30136411 · doi:10.1002/dta.2489[Analytical, grade D]
- Sinha DK, Balasubramanian A, Tatem AJ et al. (2020). Beyond the androgen receptor: the role of growth hormone secretagogues in the modern management of body composition in hypogonadal males. Transl Androl Urol. PubMed 32257855 · doi:10.21037/tau.2019.11.30[Review, grade R]
- PubChem, National Library of Medicine. Ipamorelin (CID 9831659). Source[retrieved 2026-11-11]
- U.S. Food and Drug Administration, openFDA. openFDA Drugs@FDA and NDC directory queries for ipamorelin. Source[retrieved 2026-11-11]
- U.S. Food and Drug Administration (2024-10-29). October 29, 2024: Meeting of the Pharmacy Compounding Advisory Committee. Source[retrieved 2026-11-11]