Sermorelin vs Tesamorelin: Differences, Evidence and Status

By Editorial team. Updated Oct 15, 2026. Awaiting expert review

Sermorelin and tesamorelin are both copies of growth hormone-releasing hormone (GHRH), and both prompt the pituitary gland to release the body’s own growth hormone [1, 7]. Sermorelin is a shortened, 29-amino-acid version; tesamorelin is the full 44-amino-acid hormone with a small chemical group added that slows its breakdown [1, 3, 4]. The bigger difference is regulatory. Tesamorelin is a current US prescription medicine, Egrifta, for one condition: excess abdominal fat in people with HIV [5, 7]. Sermorelin was approved in the US as Geref, but the products were discontinued in 2008 [2].

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 [1]. A 2026 review describes it as GHRH(1–29) and as short-acting, with a disappearance half-time of about four minutes [13]. FDA approved it as Geref: in 1990 as a test of the pituitary’s ability to release growth hormone, and in 1997 to treat idiopathic growth hormone deficiency in children with growth failure [2]. EMD Serono, which held both applications, discontinued the products in 2008, and in 2013 FDA determined that they had not been withdrawn for reasons of safety or effectiveness [2].

Tesamorelin, developed under the code TH9507, is GHRH(1–44), the full-length hormone [4]. Its one change is a trans-3-hexenoyl group attached to the first amino acid [3, 13]. In laboratory and animal tests, this made it resistant to DPP-4, an enzyme that inactivates natural GHRH, and slowed its breakdown in plasma [3].

How the evidence compares

Tesamorelin has the stronger human evidence, for a narrow use. In a 26-week trial of 412 people with HIV and excess abdominal fat, visceral (deep abdominal) fat fell by 15.2% with tesamorelin and rose by 5.0% with placebo [6]. A pooled analysis of two phase 3 trials with 806 patients found that the reduction was maintained for up to 52 weeks in those who continued treatment [4], and a review found that the fat came back after treatment stopped [7]. Reviewers found only limited data supporting uses beyond HIV-associated fat accumulation [8], and a 2026 review for sports-medicine physicians found no orthopedic evidence for tesamorelin [10].

Sermorelin’s human data are older and mostly in children. It was used as a diagnostic test for growth hormone deficiency and, based on limited data, to treat some children with idiopathic growth hormone deficiency [1]. The 1999 review noted that the recommended sermorelin regimen hadn’t been compared directly with somatropin (growth hormone itself), and that growth gains with some other ways of giving sermorelin were smaller than with somatropin [1]. In adults, a 2020 review of growth hormone secretagogues, sermorelin among them, found clinical data on men with low testosterone largely lacking [9].

Regulation and sport

Today tesamorelin is an approved prescription medicine in the US [5], while sermorelin’s products were discontinued in 2008 and FDA withdrew both approvals effective June 18, 2009 [2]. WADA prohibits both at all times as growth hormone-releasing hormone analogues [11].

Quality risks when buying

In the US, Egrifta is available only on prescription [5]. Vials sold as research-grade tesamorelin or sermorelin come from unregulated supply chains, where a 2026 review notes uncertain quality and composition [13]. Anti-doping laboratories testing black-market growth-promoting products have found modified versions of known peptides, identified using high-resolution mass spectrometry [12].

So a batch certificate of analysis (COA) should confirm the molecule’s identity by mass spectrometry and give a measured purity, not just a label claim. Our guides explain how to read a COA, how to check a vendor and what “research use only” means.

For more detail, see our sermorelin overview and tesamorelin overview, and today’s prices for sermorelin and tesamorelin. Related comparisons: CJC-1295 vs sermorelin and ipamorelin vs sermorelin.