Ipamorelin vs Sermorelin: Differences, Evidence and Status
Ipamorelin vs Sermorelin at a glance
| Fact | Ipamorelin | Sermorelin |
|---|---|---|
| Also known as | Ipamorelin acetate | GRF (1-29), Geref, Sermorelin acetate |
| What it is | Synthetic growth hormone secretagogue (pentapeptide) | Synthetic GHRH(1-29) analogue (formerly approved in the US) |
| Evidence level | Early human trials | Formerly approved drug (approvals withdrawn) |
| Approved products | None | Geref (discontinued) (US, 1990); Geref (discontinued) (US, 1997) |
| United States | Not FDA-approved; FDA lists ipamorelin acetate in Category 2 (significant safety risks) for outsourcing-facility compounding, and its nomination for pharmacy compounding was withdrawn [11][4]. | Approved by the FDA as Geref in 1990 and 1997; both products were discontinued in 2008, and FDA withdrew both approvals effective June 18, 2009 [20][21][6]. |
| United Kingdom | No UK-licensed medicine containing ipamorelin appears in the MHRA products database [13]. | No UK-licensed medicine containing sermorelin appears in the MHRA products database [22]. |
| European Union | No medicine containing ipamorelin is authorized in the EU, according to EMA's central and Article 57 product data [14][15]. | No medicine containing sermorelin is authorized in the EU, according to EMA's central and Article 57 product data [14][15]. |
| Canada | No product containing ipamorelin appears in Health Canada's Drug Product Database [16]. | No product containing sermorelin appears in Health Canada's Drug Product Database [16]. |
| Australia | Schedule 4 (prescription-only) in Australia's Poisons Standard, with possession without authority prohibited under Appendix D [17]. | Schedule 4 (prescription-only) in Australia's Poisons Standard, which also lists growth hormone releasing hormones (GHRHs), including those named separately in Schedule 4, among poisons that must not be possessed without authority (Appendix D) [17]. |
| Sport (WADA) | Named as a prohibited growth hormone secretagogue under S2 [9]. | Named as a prohibited growth hormone-releasing hormone analogue under S2 [9]. |
| Vendors we track | 77 vendors | 62 vendors |
| Our lab tests | None yet | None yet |
Ipamorelin and sermorelin both make the pituitary gland release growth hormone, but they work through different receptors. Sermorelin is a shortened version of growth hormone-releasing hormone (GHRH) with the hormone’s full activity [5]. Ipamorelin is a small synthetic peptide that acts on the ghrelin receptor [2], the receptor used by the growth hormone-releasing peptides (GHRPs) such as GHRP-6 [1]. A 2026 review accordingly groups sermorelin with the GHRH analogues and ipamorelin with the growth hormone secretagogues [8]. Sermorelin was an FDA-approved drug until 2009: its products were discontinued in 2008, and FDA withdrew both approvals effective June 18, 2009 [6]; ipamorelin reached a phase 2 trial but has never been FDA-approved [2, 11].
What each one is
Sermorelin is a 29-amino-acid analogue of human GHRH and the shortest synthetic peptide with the hormone’s full biological activity [5]. It stimulates growth hormone secretion from the anterior pituitary [5].
Ipamorelin is a five-amino-acid peptide, Aib-His-D-2-Nal-D-Phe-Lys-NH2 [1], and FDA notes that it contains unnatural amino acids [4]. Its developers used receptor-blocking drugs to show that, like GHRP-6, it releases growth hormone through a GHRP-type receptor [1]. In pigs, GHRP-6 and GHRP-2 raised the hormones ACTH and cortisol, while ipamorelin raised them no more than GHRH did [1].
How the evidence compares
Sermorelin. FDA approved it as Geref in 1990 to test the pituitary’s ability to release growth hormone, and in 1997 to treat idiopathic growth hormone deficiency in children with growth failure [6]. A 1999 review described limited treatment data in children and well-tolerated use, with facial flushing and injection-site pain the most common adverse events [5].
Ipamorelin. In healthy male volunteers it had a terminal half-life of about two hours and produced a single pulse of growth hormone, and responses varied more between people than drug levels did [3]. Its main clinical test was in postoperative ileus, slow bowel recovery after surgery: in a phase 2 trial of 117 bowel-resection patients, it did not significantly shorten the time to tolerating a solid meal compared with placebo [2]. FDA notes that a published study identified serious adverse events, including death, when ipamorelin was given intravenously to improve gastric motility [4].
Both. A 2020 review of growth hormone secretagogues, including sermorelin and ipamorelin, found clinical data on body composition in men with low testosterone largely lacking [7]. A 2026 sports-medicine review lists both among peptides marketed directly to patients for injury recovery and athletic performance, and notes that rigorous human safety data for unapproved peptides are scarce [12].
Regulation and sport
Ipamorelin has never been FDA-approved, and FDA lists ipamorelin acetate among bulk substances that may present significant safety risks in compounding [11, 4]. WADA prohibits both at all times: sermorelin as a GHRH analogue and ipamorelin as a growth hormone secretagogue [9].
Quality risks when buying
Neither is sold as an approved medicine in the US today [6, 11], and research-grade vials are unregulated [8]. FDA says compounded ipamorelin may cause immune reactions because of aggregation or peptide-related impurities, and that its unnatural amino acids make it harder to characterize [4]. Analysis of products seized by Danish customs found ipamorelin with an extra glycine added, alongside similar variants of other growth hormone secretagogues [10].
So a batch certificate of analysis (COA) should confirm identity by mass spectrometry, not just report purity. Our guides explain how to read a COA, how to check a vendor and what “research use only” means.
For more detail, see our ipamorelin overview and sermorelin overview, and today’s prices for ipamorelin and sermorelin. Related: sermorelin vs tesamorelin and CJC-1295 vs sermorelin.
Frequently asked questions
What is the difference between ipamorelin and sermorelin?
Both make the pituitary gland release growth hormone, but through different receptors. Sermorelin is a 29-amino-acid version of growth hormone-releasing hormone and acts like that hormone. Ipamorelin is a five-amino-acid peptide that acts on the ghrelin receptor, like the growth hormone-releasing peptides.
Is ipamorelin FDA-approved?
No. It reached a phase 2 trial for slow bowel recovery after surgery, which found no significant difference from placebo, and it has never been FDA-approved.
Was sermorelin ever approved?
Yes, as Geref, from 1990. Both Geref products were discontinued in 2008, and FDA determined in 2013 that they were not withdrawn for reasons of safety or effectiveness.