# Sermorelin vs tesamorelin: what separates two copies of the same hormone

> Source: https://peptidewellnessusa.com/peptides/compare/sermorelin-vs-tesamorelin/
> Compare · Growth hormone
> By PeptideWellness Editorial Team · Medically reviewed by Ksenia Petrushkina, PA-C, MPAS · Updated October 22, 2026 · 6 min read

Both molecules copy the hormone the hypothalamus uses to switch on growth hormone, and both act on the same receptor. Tesamorelin has two Phase 3 trials and a current FDA label for one narrow use. Sermorelin has a withdrawn approval, very little adult data, and the one thing tesamorelin lacks: a legal route through a compounding pharmacy.

Sermorelin and tesamorelin are both versions of growth hormone-releasing hormone, GHRH, the signal the hypothalamus sends to the pituitary when it is time to release growth hormone. Neither is growth hormone. Both ask the pituitary to make its own.

That is where the similarity ends. One has a current FDA label backed by two large randomised trials, for a single use in people with HIV. The other lost its approval for business reasons in 2008 and is now prepared by compounding pharmacies for uses nobody has tested properly. And because of a 2020 change in how FDA classifies large peptides, the better-studied of the two is the one a pharmacy cannot legally compound.

No trial has compared them directly. A PubMed search on 22 October 2026 for papers naming both returns reviews and doping-control methods, no head-to-head study, and ClinicalTrials.gov lists none either. Everything below compares each drug's own evidence.

## Same receptor, different length

Native GHRH is a chain of 44 amino acids. [Sermorelin](https://peptidewellnessusa.com/peptides/sermorelin/) is its first 29, the shortest fragment that keeps full activity at the GHRH receptor [1]. [Tesamorelin](https://peptidewellnessusa.com/peptides/tesamorelin/) is the full 44-amino-acid sequence with a six-carbon hexenoyl group attached to the first amino acid [2]. In the developer's laboratory work that one addition made the molecule resistant to DPP-4, the enzyme that inactivates native GHRH, and slowed its breakdown in plasma [3].

Both bind the same receptor on the somatotroph cells of the anterior pituitary, and both leave the body's brakes in place: somatostatin still shuts the pulse down when growth hormone and IGF-1 rise. That is the shared argument for this whole class over injecting growth hormone itself.

Neither stays in the blood long. Native GHRH has an intravenous half-life of under seven minutes [4]. The Egrifta WR label gives tesamorelin an elimination half-life of 11 minutes after a subcutaneous dose [2]. The hexenoyl group makes tesamorelin harder to break down, but neither is a long-acting drug.

## What tesamorelin's trials showed

Tesamorelin was approved in 2010 as Egrifta for one indication: reducing excess abdominal fat in adults with HIV who have lipodystrophy, a redistribution of fat that some antiretroviral regimens cause [5]. The current product, Egrifta WR, was approved in March 2025 at 1.28 mg injected once a day [2].

The approval rests on two 26-week placebo-controlled trials, both measuring visceral fat, the fat around the organs, by CT scan [2][6][7]:

|  | Study 1 | Study 2 |
| --- | --- | --- |
| Patients on tesamorelin / placebo | 273 / 137 | 270 / 126 |
| Visceral fat change, tesamorelin | −18% | −14% |
| Visceral fat change, placebo | +2% | −2% |
| Difference | −20% (95% CI −24 to −15) | −12% (95% CI −16 to −7) |
| Body weight change, tesamorelin | −0.4 kg | +0.5 kg |

The last row matters as much as the first. Tesamorelin moved fat out of the abdomen without changing body weight in either trial, and its label says plainly that it is not indicated for weight loss [2]. Waist circumference fell by one to two centimetres more than with placebo.

Outside HIV, the strongest data is a 20-week randomised trial in 152 adults aged 55 to 87, with and without mild cognitive impairment, which found improved executive function on tesamorelin against placebo [8]. A trial in people with HIV and fatty liver disease found a reduction in liver fat [9]. Neither led to a new indication.

## What sermorelin's trials showed

Sermorelin's approval, as Geref, was for children with idiopathic growth hormone deficiency [10]. The paediatric trials supported that use, and the drug was on the market for over a decade.

The adult evidence is thin. The most cited study measured 9 young and 10 older men, then gave the older men GHRH(1-29) twice daily for 14 days at two doses; the higher dose brought their growth hormone and IGF-1 up toward the levels of the younger group [11]. The longest controlled study used a close analogue of sermorelin in 19 adults aged 55 to 71, with four weeks of placebo followed by 16 weeks of treatment, and again measured hormone levels [12]. There is no Phase 3 trial of sermorelin in adults, and a PubMed search for randomised trials of sermorelin in adults returns nothing.

So the two drugs are not on the same evidential footing. Tesamorelin has 806 patients across two controlled trials with an imaging endpoint. Sermorelin has a few dozen adults, short follow-up, and blood tests.

## Why the approvals ended up where they are

Sermorelin's maker, EMD Serono, stopped selling Geref in 2008 and asked FDA to withdraw the approvals, which it did in 2009 [13]. In 2013 FDA published a determination that Geref was not withdrawn for reasons of safety or effectiveness [14]. That determination is what allows compounding pharmacies to prepare sermorelin today under section 503A, for an individual patient with a prescription.

Tesamorelin went the other way. In February 2020 FDA defined a protein as any chain of more than 40 amino acids [15], and on 23 March 2020 products that met that definition moved from the drug framework to the biologics framework. Tesamorelin, at 44 amino acids, was one of them: the Egrifta labels now carry a biologics licence number, BLA 022505 [2]. FDA's notice to compounders that month said these transitioning biological products are not eligible for the compounding exemptions in sections 503A and 503B [16].

The practical result is the reverse of what the evidence would suggest. The drug with the trials can be obtained lawfully only as branded Egrifta, prescribed for its label or off label. The drug without them is the one a compounding pharmacy may make. Compounded "tesamorelin" is sold online all the same; our [regulatory tracker](https://peptidewellnessusa.com/learn/peptide-regulatory-tracker/) sets out where each peptide stands.

## Side effects and who should not use them

Tesamorelin's label lists arthralgia, injection-site redness and itching, pain in the arms and legs, swelling of the extremities and muscle pain as the most common reactions, all above 5% of patients [2]. It can raise blood glucose, so people with diabetes or impaired glucose tolerance are monitored. It is contraindicated in active cancer, in people whose pituitary has been damaged or removed, in pregnancy, and in people allergic to it.

Sermorelin has no current label. The safety record comes from its paediatric approval and the small adult studies, and it is reassuring as far as it goes; long-term adult data does not exist. The same cancer caution applies in principle to anything that raises growth hormone and IGF-1.

Both drugs depend on a working pituitary. If the gland itself is damaged, neither will do much, and that is a case for growth hormone, not for a releasing hormone.

## Side by side

|  | Sermorelin | Tesamorelin |
| --- | --- | --- |
| What it is | GHRH(1-29), 29 amino acids | Full GHRH(1-44) plus a hexenoyl group |
| Receptor | GHRH receptor | GHRH receptor |
| FDA status | Approval withdrawn 2009, not for safety | Approved in 2010 as Egrifta; current product Egrifta WR |
| Approved use | Formerly: children with GH deficiency | Excess abdominal fat in adults with HIV lipodystrophy |
| Largest controlled human evidence | Small paediatric and adult studies | Two 26-week Phase 3 trials, 806 patients |
| Regulated as | Drug | Biologic, since March 2020 |
| Compounding under 503A | Permitted with a prescription | Not eligible |
| Usual dosing | Not set for adults; prescriber decides | 1.28 mg once daily (Egrifta WR) |

## How to read the choice

If the question is which molecule has shown it does something measurable in people, it is tesamorelin, and for visceral fat in HIV-associated lipodystrophy the answer is settled. If the question is which one a telehealth clinic can lawfully send you from a compounding pharmacy, it is sermorelin.

For anyone outside the approved indication, that leaves an uncomfortable choice between a drug with good data that you would have to obtain as a branded product off label, and a drug with little data that is easy to get. Neither has been shown to slow ageing, build muscle or cause weight loss in healthy adults. A prescriber who checks IGF-1 before and during treatment is the minimum. The wider set of options is laid out in our [longevity protocol](https://peptidewellnessusa.com/protocols/longevity/), and the third common peptide in this group is compared with each of these in [sermorelin vs ipamorelin](https://peptidewellnessusa.com/peptides/compare/sermorelin-vs-ipamorelin/) and [tesamorelin vs ipamorelin](https://peptidewellnessusa.com/peptides/compare/tesamorelin-vs-ipamorelin/).

## Frequently asked

### Is tesamorelin stronger than sermorelin?

There is no trial that compares them, so nobody can say which raises growth hormone more at a given dose. Tesamorelin is the one with Phase 3 evidence of an effect on body fat; sermorelin's adult evidence is limited to small studies of hormone levels.

### Does tesamorelin cause weight loss?

No. In both Phase 3 trials body weight barely changed while visceral fat fell by 14% to 18%, and the label states that it is not indicated for weight loss.

### Can a compounding pharmacy make tesamorelin?

Not lawfully. Since March 2020 tesamorelin has been regulated as a biologic, and FDA has said that transitioning biologics are not eligible for compounding under sections 503A and 503B. Sermorelin, a 29-amino-acid peptide, is still a drug and can be compounded for an individual prescription.

### Why is sermorelin not FDA-approved any more?

Its maker stopped selling it in 2008 for commercial reasons. FDA withdrew the approvals in 2009 and confirmed in 2013 that the withdrawal was not for safety or effectiveness.

### Can they be taken together?

They act on the same receptor, so combining them adds nothing mechanistically and has never been studied. The combinations clinics sell pair a GHRH-type peptide with a ghrelin-receptor peptide such as ipamorelin, which works through a different pathway.

## References

1. [Cervini LA, Donaldson CJ, Koerber SC, et al. Human growth hormone-releasing hormone hGHRH(1-29)-NH2: systematic structure-activity relationship studies](https://pubmed.ncbi.nlm.nih.gov/9513600/)
2. [EGRIFTA WR (tesamorelin) for injection — prescribing information, revised March 2025, BLA 022505. DailyMed](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=839334d3-8c1d-4c26-9036-2ab524a6ea75)
3. [Ferdinandi ES, Brazeau P, High K, et al. Non-clinical pharmacology and safety evaluation of TH9507, a human growth hormone-releasing factor analogue. *Basic Clin Pharmacol Toxicol.* 2007;100(1):49-58. PMID 17214611.](https://pubmed.ncbi.nlm.nih.gov/17214611/)
4. [Frohman LA, Downs TR, Williams TC, et al. Rapid enzymatic degradation of growth hormone-releasing hormone by plasma in vitro and in vivo to a biologically inactive product cleaved at the NH2 terminus. *J Clin Invest.* 1986;78(4):906-13. PMID 3093533.](https://pubmed.ncbi.nlm.nih.gov/3093533/)
5. [FDA — Egrifta (tesamorelin) approval, November 2010.](https://www.accessdata.fda.gov/drugsatfda_docs/nda/2010/022505Orig1s000Approv.pdf)
6. [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;357:2359-70. PMID 18057338.](https://pubmed.ncbi.nlm.nih.gov/18057338/)
7. [Falutz J, Mamputu JC, Potvin D, et al. Effects of tesamorelin (TH9507), a growth hormone-releasing factor analog, in human immunodeficiency virus-infected patients with excess abdominal fat: a pooled analysis of two multicenter, double-blind placebo-controlled phase 3 trials with safety extension data. *J Clin Endocrinol Metab.* 2010;95(9):4291-304. PMID 20554713.](https://pubmed.ncbi.nlm.nih.gov/20554713/)
8. [Baker LD, Barsness SM, Borson S, et al. Effects of growth hormone-releasing hormone on cognitive function in adults with mild cognitive impairment and healthy older adults: results of a controlled trial. *Arch Neurol.* 2012;69(11):1420-9. PMID 22869065.](https://pubmed.ncbi.nlm.nih.gov/22869065/)
9. [Stanley TL, Fourman LT, Feldpausch MN, et al. Effects of tesamorelin on non-alcoholic fatty liver disease in HIV: a randomised, double-blind, multicentre trial. *Lancet HIV.* 2019;6(12):e821-e830. PMID 31611038.](https://pubmed.ncbi.nlm.nih.gov/31611038/)
10. [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](https://pubmed.ncbi.nlm.nih.gov/18031173/)
11. [Corpas E, Harman SM, Piñeyro MA, et al. Growth hormone (GH)-releasing hormone-(1-29) twice daily reverses the decreased GH and insulin-like growth factor-I levels in old men. *J Clin Endocrinol Metab.* 1992;75(2):530-5. PMID 1379256.](https://pubmed.ncbi.nlm.nih.gov/1379256/)
12. [Khorram O, Laughlin GA, Yen SS. Endocrine and metabolic effects of long-term administration of Nle27growth hormone-releasing hormone-(1-29)-NH2 in age-advanced men and women. *J Clin Endocrinol Metab.* 1997;82(5):1472-9. PMID 9141536.](https://pubmed.ncbi.nlm.nih.gov/9141536/)
13. [Federal Register — withdrawal of approval of the Geref (sermorelin acetate) applications, 19 May 2009.](https://www.govinfo.gov/content/pkg/FR-2009-05-19/html/E9-11628.htm)
14. [Federal Register 2013-04827 — determination that Geref (sermorelin acetate) was not withdrawn from sale for reasons of safety or effectiveness.](https://www.federalregister.gov/documents/2013/03/04/2013-04827/determination-that-geref-sermorelin-acetate-injection-05-milligram-base-vial-and-10-milligram-base-vial-and)
15. [FDA — Definition of the term "biological product", final rule. Federal Register 2020-03505, 21 February 2020.](https://www.federalregister.gov/documents/2020/02/21/2020-03505/definition-of-the-term-biological-product)
16. [FDA — Notice to compounders: changes that affect compounding as of March 23, 2020.](https://www.fda.gov/drugs/human-drug-compounding/notice-compounders-changes-affect-compounding-march-23-2020)

## Medical disclaimer

This page is informational and is not medical advice. It compares published evidence and regulatory status; it cannot tell you whether either drug is appropriate for you. Both raise growth hormone and IGF-1, both are unsuitable for people with active cancer, and tesamorelin can raise blood glucose. Whether to start, what dose to use and how to monitor it are decisions for a licensed prescriber who knows your medical history. Last reviewed October 2026.