Sermorelin vs ipamorelin

What each one is

Sermorelin is a 29-amino-acid analog of human growth-hormone-releasing hormone (GHRH). Given into a vein or under the skin, it stimulates the pituitary gland to secrete growth hormone.¹

Ipamorelin is a five-amino-acid peptide that releases growth hormone through a different receptor, the one used by growth-hormone-releasing peptides (GHRPs). Its developers described it in 1998 as the first agonist of that receptor with a selectivity for growth hormone release similar to that of GHRH: in pigs it did not raise ACTH or cortisol, unlike two older GHRPs.² That paper reports laboratory and animal work.

A 2026 review classes sermorelin among GHRH analogs and ipamorelin among growth hormone secretagogues.³

Regulatory status in the United States

Sermorelin was the active ingredient of an FDA-approved injection, Geref, approved in 1990 and 1997. The manufacturer discontinued it in 2008, and the FDA determined that it had not been withdrawn for reasons of safety or effectiveness.⁴

The FDA lists ipamorelin acetate among the bulk drug substances that may present significant safety risks when used in compounding. The agency cites a risk of immune reactions for certain routes of administration, and a published study that "identified serious adverse events including death when ipamorelin was administered intravenously" to improve gastric motility. It adds that it lacks information to know whether the substance would cause harm by other injectable routes.⁵

Sermorelin does not appear on that FDA page, which we read on November 12, 2026.⁵

Both are sold online as compounded drugs. Compounded drugs are not FDA-approved.⁶

Human studies

Ipamorelin was tested in a phase 2 trial in 117 adults recovering from bowel surgery, given into a vein twice a day for up to seven days. It was well tolerated, and there were no significant differences from placebo on the main or secondary measures of efficacy.⁷

For sermorelin, the studies in adults are small and short. They are summarized in what the studies report.

What this means when you compare providers

Our comparison covers sermorelin only. If a provider offers a blend that adds ipamorelin, the price and the terms on its sermorelin page do not apply to the blend, and the FDA's statement about ipamorelin above does.

Sources

1. Prakash A, Goa KL. Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency. BioDrugs. 1999;12(2):139-57. Read November 12, 2026.
2. Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998;139(5):552-61. Read November 12, 2026.
3. Dominikowski A, et al. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis. Front Endocrinol (Lausanne). 2026;17:1822475. Read November 12, 2026.
4. FDA, Federal Register, March 4, 2013: Determination that Geref (sermorelin acetate) injection was not withdrawn from sale for reasons of safety or effectiveness. Read November 12, 2026.
5. FDA, Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of April 22, 2026). Read November 12, 2026.
6. FDA, Compounding and the FDA: Questions and Answers. Read November 12, 2026.
7. Beck DE, et al. 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. 2014;29(12):1527-34. Read November 12, 2026.