The short version: both are GHRH analogues that act on the same pituitary receptor. Tesamorelin is the full hormone with a hexenoyl cap on the front, licensed in the US since 2010 for one narrow use in people with HIV. Sermorelin is the first 29 residues, licensed in the US from 1990 until the maker stopped selling it in 2008. Tesamorelin's evidence is large phase 3 trials; sermorelin's is older and smaller.
Side by side
| Point | Tesamorelin | Sermorelin |
|---|---|---|
| Based on | Human GHRH (1–44) | Human GHRH (1–29) |
| Modification | Hexenoyl cap on tyrosine 1 | None; C-terminal amide |
| Length | 44 residues | 29 residues |
| Avg mass | 5135.9 g/mol | 3357.9 g/mol |
| CAS | 218949-48-5 | 86168-78-7 |
| Developer | Theratechnologies (TH9507) | Salk Institute patent; Serono |
| Half-life | 26 to 38 minutes5 | Short; not stated in a single figure in the sources we have |
| Main trials | Two phase 3 trials, 412 and 404 adults with HIV, 26 weeks3,4 | Open-label study in 110 children; small studies in older men8,9,10 |
| Licensed | US, since 2010, for abdominal fat in HIV lipodystrophy2 | US 1990–2009; discontinued, not for safety reasons7 |
| UK, EU | Not authorised | Not currently authorised |
| WADA | S2.2.4 · named | S2.2.4 · named |
Full hormone or first 29 residues
Natural GHRH is 44 residues long and lasts minutes in blood, because an enzyme cuts the bond after the second residue. The two analogues deal with that differently. Tesamorelin keeps the whole sequence and blocks the cut with a small fatty group on the first residue.1 Sermorelin drops the last 15 residues, which the 1984 work showed are not needed for activity at the pituitary, and leaves the front end unprotected.11
CJC-1295 sits between them: the same 29 residues as sermorelin with four substitutions and an albumin-binding lysine, which stretches its half-life to days. See the CJC-1295 comparison.
What the trials measured
| Study | Compound | People | What was measured | Finding |
|---|---|---|---|---|
| Falutz 2007 | Tesamorelin | 412 adults with HIV and abdominal fat, 26 weeks | Visceral fat by CT, IGF-1, lipids, glucose | Visceral fat down 15.2% against up 5.0% on placebo3 |
| Falutz 2010 | Tesamorelin | 404 adults with HIV | Visceral fat, body image, lipids | Confirmed the first trial4 |
| Stanley 2019 | Tesamorelin | 61 adults with HIV and fatty liver, 12 months | Liver fat and fibrosis | Liver fat reduced12 |
| Thorner 1996 | Sermorelin | 110 children with growth hormone deficiency, open-label | Height velocity | Rose from 4.1 to 8.0 cm a year at 6 months8 |
| Corpas 1992 | Sermorelin | 10 older men, 9 young men, 14 days | Growth hormone and IGF-1 | Older men reached young-adult levels9 |
| Vittone 1997 | Sermorelin | 11 men aged 64 to 76, 6 weeks | Growth hormone, IGF-1, body composition | Night-time growth hormone rose; body composition unchanged10 |
What this means for a readerIf the question is what a GHRH analogue does to body fat in adults, the tesamorelin trials are the primary evidence, and they are all in people with HIV. If the question is growth hormone release itself, both compounds have shown it; the sermorelin data are older, smaller and mostly in children or in short studies of older men.
Licensing and sport
Tesamorelin is prescription-only in the US for one use: reducing excess abdominal fat in adults with HIV and lipodystrophy. It is not authorised in the UK or the EU.2 Sermorelin was approved in the US in 1990 as a diagnostic and in 1997 for growth hormone deficiency in children; the sponsor discontinued it in 2008, and in 2013 the FDA ruled that it had not been withdrawn for reasons of safety or effectiveness. It was licensed nationally in Ireland from 1991 to 2007.7,13
Both are named in WADA class S2.2.4, "growth hormone-releasing hormone and its analogues", and prohibited at all times.14
Common questions
What is the difference between tesamorelin and sermorelin?
Length and protection. Tesamorelin is all 44 residues of GHRH with a protective hexenoyl cap on the front. Sermorelin is the first 29 residues with no cap.
Which one is approved?
Tesamorelin, in the US, since 2010, for abdominal fat in adults with HIV and lipodystrophy. Sermorelin was approved in the US from 1990 but the maker stopped selling it in 2008. Neither is authorised in the UK or the EU.
Why was sermorelin withdrawn?
The sponsor discontinued it. In 2013 the FDA ruled that the withdrawal was not for reasons of safety or effectiveness.
Do they act on the same receptor?
Yes. Both act on the GHRH receptor in the pituitary and release growth hormone.
Are tesamorelin and sermorelin banned in sport?
Yes, both by name, under WADA class S2.2.4, prohibited at all times.
References
- Ferdinandi ES, et al. Non-clinical pharmacology and safety evaluation of TH9507, a human growth hormone-releasing factor analogue. Basic Clin Pharmacol Toxicol. 2007. PMID 17214611
- US Food and Drug Administration. Egrifta (tesamorelin for injection) prescribing information, approved November 2010.
- Falutz J, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med. 2007;357:2359–2370. PMID 18057338
- Falutz J, et al. Effects of tesamorelin, a growth hormone-releasing factor, in HIV-infected patients with abdominal fat accumulation: a randomized placebo-controlled trial with a safety extension. J Acquir Immune Defic Syndr. 2010;53(3):311–322. PMID 20101189
- Dhillon S. Tesamorelin: a review of its use in the management of HIV-associated lipodystrophy. Drugs. 2011. PMID 21668043
- 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. PMID 18031173
- US Food and Drug Administration. Determination that GEREF (sermorelin acetate) injection was not withdrawn from sale for reasons of safety or effectiveness. Federal Register. 4 March 2013;78(42):14095–14096.
- Thorner M, et al. Once daily subcutaneous growth hormone-releasing hormone therapy accelerates growth in growth hormone-deficient children during the first year of therapy. J Clin Endocrinol Metab. 1996;81(3):1189–1196. PMID 8772599
- Corpas E, 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):530–535. PMID 1379256
- Vittone 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. PMID 9005976
- Ling N, et al. Synthesis and in vitro bioactivity of C-terminal deleted analogs of human growth hormone-releasing factor. Biochem Biophys Res Commun. 1984;123(2):854–861. PMID 6435620
- Stanley TL, 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.
- Health Products Regulatory Authority (Ireland). GEREF 50, licence PA0285/006/001: authorised 26 July 1991, withdrawn 6 July 2007. hpra.ie
- World Anti-Doping Agency. The 2026 Prohibited List, class S2.2.4. wada-ama.org
Peptidarium Library. Tesamorelin vs sermorelin (comparison 05), 2 November 2026. peptidarium.com/compare/tesamorelin-vs-sermorelin