Sermorelin and tesamorelin are both synthetic analogs of human growth hormone-releasing hormone (GHRH), and both have, at different times, carried FDA approval — but that is close to where the similarity in their regulatory stories ends. Sermorelin (Geref) was approved for diagnostic use in 1990 and for pediatric growth hormone deficiency in 1997, then discontinued commercially in 2008; the FDA's 2013 review of that withdrawal formally concluded it was "not withdrawn from sale for reasons of safety or effectiveness" [5]. Tesamorelin (Egrifta) was approved in 2010 for a different indication — reducing excess visceral abdominal fat in HIV-associated lipodystrophy — and remains on the market today, reformulated twice since as Egrifta SV (2019) and Egrifta WR (2025) [4][6][7][8]. It is the only GHRH-class peptide with current FDA approval.
This page compares what the published literature reports for each molecule — chemistry, trial evidence, and regulatory history — not which one a researcher should prefer. No randomized trial has ever tested sermorelin against tesamorelin head-to-head, and the two evidence bases come from different eras, different patient populations, and different approved (or formerly approved) indications, so any comparison here draws on separate trial programs rather than a shared experimental design. For full single-compound coverage, see the dedicated articles on sermorelin and tesamorelin.
Side-by-Side Overview
| Sermorelin | Tesamorelin | |
|---|---|---|
| Molecule / backbone | Truncated 29-amino-acid GHRH fragment, GRF(1-29)-NH2, retaining native methionine at position 27 (PubChem) | Full-length 44-amino-acid GHRH backbone with an added N-terminal trans-3-hexenoyl group [4] |
| Stabilization strategy | Amidated amino-terminal 29-residue GHRH fragment; the [Nle27] analog studied in some research is a distinct molecule [2] | Acylation of the intact 44-residue hormone to resist the rapid enzymatic degradation that limits native GHRH, while leaving the core sequence unchanged [4] |
| Regulatory history | Approved as Geref: 1990 (diagnostic), 1997 (pediatric GHD); discontinued commercially 2008; FDA determined in 2013 the withdrawal was not safety- or efficacy-related [2][5] | Approved as Egrifta in 2010; reformulated as Egrifta SV (2019) and Egrifta WR (2025), continuously marketed since [6][7][8] |
| Current FDA status | Not FDA-approved for any indication; contemporary compounded preparations do not inherit Geref’s FDA review | FDA-approved prescription medicine, dispensed through licensed pharmacies under medical supervision |
| Approved indication(s) | Historical: GH-stimulation diagnostic testing; pediatric growth hormone deficiency | Reduction of excess visceral abdominal fat in adults with HIV-associated lipodystrophy |
| Pivotal trial evidence | Pediatric GHD program: sustained height-velocity gains over 12 months, data suggesting persistence to 36 months [2]; GHRH-arginine combined test validated as a practical alternative to insulin tolerance testing [9][10] | Two phase 3 RCTs (n=412, n=404; pooled n=806): VAT −15.2% vs +5.0% placebo at 26 weeks (trial 1); pooled treatment effect −15.4% at week 26, sustained through week 52 [4][15][16] |
| Trial era and scale | Nearly all controlled data from the mid-1980s through late 1990s; sample sizes in the tens of subjects [2][11][12][13] | Phase 3 program 2007–2010; liver-fat, NAFLD, and cognition sub-literatures 2011–2024; two independent meta-analyses published 2026 |
| Half-life / PK | Short-acting fragment; the pediatric and adult trials used once-daily (or single) subcutaneous dosing [2][9] | Short-acting native-length hormone; N-terminal acylation supports once-daily subcutaneous dosing across all phase 3 and mechanistic trials [4][20] |
| Evidence depth today | Frozen at roughly 1999; no dedicated modern RCT program; current clinical use governed by compounding-pharmacy oversight rather than new-drug review [2][5] | Active and expanding: liver-fat, NAFLD, cognition, and INSTI-era sub-literatures plus two 2026 systematic reviews/meta-analyses [17][18] |
The Shared Design Problem: A Hormone That Degrades Too Fast
Both molecules exist because native, full-length GHRH is not a practical drug on its own — a review of GHRH pharmacology across health and disease describes the hormone as subject to rapid enzymatic inactivation in circulation, a constraint that has shaped essentially every attempt to turn it into an injectable therapy [3]. Sermorelin and tesamorelin represent two different engineering answers to that same problem. Sermorelin's approach, worked out through structure-activity studies in the early 1980s, was truncation: the amino-terminal 29 residues of the 44-residue hormone, amidated at the carboxy terminus, retained full GH-releasing potency in early comparative work, while the norleucine-substituted analog used in some studies is chemically distinct from sermorelin [1][2]. Tesamorelin took the opposite path: keep the entire 44-residue native sequence, and instead attach a trans-3-hexenoyl group to the amino-terminal tyrosine to slow the degradation process directly, without shortening the hormone at all [4]. Both modifications were built for the same practical end — a molecule stable enough to support once-daily subcutaneous dosing in a clinical trial — but they arrived there by essentially opposite chemistry.
Two Regulatory Arcs, One Drug Class
Sermorelin's regulatory arc ran its full course and then reversed: an approved drug (Geref) that a manufacturer voluntarily discontinued for commercial reasons — competition from recombinant human growth hormone — after which the FDA, responding to a generic-manufacturer petition, reviewed its safety and adverse-event record and found no safety or efficacy basis for the withdrawal [5]. That determination did not restore approval; no sermorelin product has held FDA approval since 2009, and contemporary compounded preparations are subject to a different framework from new-drug review [2][5]. Tesamorelin's arc has moved only one direction since 2010: an initial approval, then two reformulations (Egrifta SV in 2019, cutting injection volume; Egrifta WR in 2025, cutting volume further and reducing reconstitution to weekly) that replaced rather than supplemented the prior version, keeping one FDA-approved tesamorelin product continuously on the market [6][7][8]. The two histories together show that "GHRH analog" is not itself a regulatory category — each molecule was reviewed, approved, and, in sermorelin's case, discontinued on its own separate record.
Comparing the Trial Evidence: Different Populations, Different Eras
The two compounds' clinical trial bases barely overlap in subject matter. Sermorelin's strongest evidence, and the basis for its original approval, is the pediatric growth hormone deficiency program: once-daily subcutaneous dosing produced sustained increases in height velocity over 12 months (a subset followed to 36 months), though the effect was generally smaller than equivalent-dose recombinant somatropin produced [2]. Its second body of evidence is diagnostic: GHRH combined with arginine became a standard, better-tolerated alternative to the insulin tolerance test for adult GH-axis testing, with BMI-adjusted peak-GH cutoffs established across multiple centers [9][10]. Beyond those two areas, sermorelin's adult evidence shrinks to two small 1990s aging-population trials — an uncontrolled GHRH(1-29) study reporting some strength changes from baseline, and a separate study of the distinct [Nle27]GHRH(1-29)-NH2 analog reporting sex-differentiated metabolic findings — plus a distinct line of research showing pulsatile GHRH dosing increases slow-wave sleep relative to continuous infusion [11][12][13].
Tesamorelin's evidence base is larger and sits in a different population: two independent, multicenter, placebo-controlled phase 3 trials in HIV-infected adults with lipodystrophy (n=412 and n=404), pooled (n=806) to a 15.4% VAT reduction versus placebo sustained through 52 weeks, plus follow-on trials adding liver-fat and NAFLD endpoints in smaller cohorts (n=50 and n=61) [4][15][16][17]. A separate research thread probed tesamorelin's effect on cognition, reporting improved executive function in older adults with and without mild cognitive impairment at a lower dose (1 mg/day) than the lipodystrophy trials used (2 mg/day) [19] — a research finding about the GHRH axis, not an approved use, just as sermorelin's aging studies are. Any comparison of trial numbers has to hold onto that population-and-era mismatch: sermorelin's pediatric-GHD and diagnostic data come from a different decade, population, and clinical question than tesamorelin's HIV-lipodystrophy program, and neither compound's aging- or cognition-related research constitutes an approved indication.
The Point Both Articles Share: Working With, Not Around, the GH Axis
Despite their different indications, sermorelin and tesamorelin share a mechanistic feature that recurs in both source literatures: each stimulates the pituitary's own GH-secreting machinery through the GHRH receptor rather than substituting for it, leaving the hypothalamic-pituitary-IGF-1 feedback loop intact [3]. A pharmacodynamic study of tesamorelin in healthy men found two weeks of dosing increased GH pulse area and basal secretion without significantly affecting fasting glucose or insulin-stimulated glucose uptake, and the authors proposed that acting upstream of GH limits the risk of supraphysiologic GH/IGF-1 elevation compared with direct GH administration [20]. Reviews of the broader GHRH/GH axis describe this as preserving pulsatile GH release and somatostatin-mediated restraint, in contrast to the flatter, sustained elevation produced by exogenous GH [3]. That is a mechanistic description reported for both compounds, not a demonstrated clinical-outcome advantage over GH therapy, and a 2025 clinical review notes that whether restoring GH/IGF-1 activity toward youthful levels produces net clinical benefit remains an open question across this drug class generally [14].
No Head-to-Head Trial Exists
Unlike some compound pairs in this library, sermorelin and tesamorelin have never been tested against each other in a randomized trial, and given their non-overlapping approved (and formerly approved) indications — pediatric GHD and diagnostic testing versus HIV-associated lipodystrophy — there is no obvious shared population or endpoint such a trial would use. Every comparison above rests on separate trial programs run decades apart, in different patients, for different regulatory purposes, and should be read with that limitation in mind rather than as evidence of one compound outperforming the other.
References
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- 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):139-157. doi:10.2165/00063030-199912020-00007 — PMID: 18031173
- Granata R, Leone S, Zhang X, et al. Growth hormone-releasing hormone and its analogues in health and disease. Nat Rev Endocrinol. 2025;21(3):180-195. doi:10.1038/s41574-024-01052-1 — PMID: 39537825
- Falutz J, Allas S, Blot K, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med. 2007;357(23):2359-2370. doi:10.1056/NEJMoa072375 — PMID: 18057338
- U.S. Food and Drug Administration. Determination That GEREF (Sermorelin Acetate) Injection, 0.5 Milligrams Base/Vial and 1.0 Milligrams Base/Vial, and GEREF (Sermorelin Acetate) Injection, 0.05 Milligrams Base/Amp, Were Not Withdrawn From Sale for Reasons of Safety or Effectiveness. Federal Register, 78 FR 14304, March 4, 2013. govinfo.gov
- U.S. Food and Drug Administration. Approval letter for NDA 22-505 (Egrifta, tesamorelin for injection). November 10, 2010. accessdata.fda.gov
- U.S. Food and Drug Administration. Egrifta SV prescribing information, supplement approvals s012/s013. 2019. accessdata.fda.gov
- Theratechnologies Inc. Theratechnologies Receives FDA Approval for EGRIFTA WR (Tesamorelin F8) to Treat Excess Visceral Abdominal Fat in Adults with HIV and Lipodystrophy. Press release, March 25, 2025. globenewswire.com
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- Corneli G, Di Somma C, Baldelli R, et al. The cut-off limits of the GH response to GH-releasing hormone-arginine test related to body mass index. Eur J Endocrinol. 2005;153(2):257-264. doi:10.1530/eje.1.01967 — PMID: 16061832
- Vittone J, Blackman MR, Busby-Whitehead J, et al. Effects of single nightly injections of growth hormone-releasing hormone (GHRH 1-29) in healthy elderly men. Metabolism. 1997;46(1):89-96. doi:10.1016/S0026-0495(97)90174-8 — PMID: 9005976
- Khorram O, Laughlin GA, Yen SSC. Endocrine and metabolic effects of long-term administration of [Nle27]growth hormone-releasing hormone-(1-29)-NH2 in age-advanced men and women. J Clin Endocrinol Metab. 1997;82(5):1472-1479. doi:10.1210/jcem.82.5.3943 — PMID: 9141536
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This article summarizes published scientific literature and public regulatory records for educational purposes only. Tesamorelin is a currently FDA-approved prescription medicine (Egrifta/Egrifta SV/Egrifta WR), indicated specifically for reducing excess visceral abdominal fat in adults with HIV-associated lipodystrophy and available only through licensed pharmacies under medical supervision. Sermorelin was formerly FDA-approved as the drug Geref; that approval was discontinued in 2009 for commercial, not safety or efficacy, reasons, and no sermorelin product currently holds FDA approval for any indication in the United States. Research-grade material for either compound sold as a laboratory reference standard is a separate category, is not a drug product, and is not for human use. Nothing here constitutes medical advice, and no statement about research materials has been evaluated by the FDA.