In this article12 sections
A lab-made copy of growth hormone-releasing hormone, the brain's signal to release growth hormone. It makes the body release more of its own. In people with HIV it cut deep belly fat by about 15% in six months, and liver fat in a later trial, but the fat came back when it stopped. Approved in the US as Egrifta; not in the UK; banned in sport.
Tesamorelin is a lab-made version of growth hormone-releasing hormone (GHRH), the signal your brain sends to the pituitary gland to release growth hormone. Instead of adding growth hormone from outside, it prompts the body to make more of its own. It is best known for large trials showing it shrinks deep belly fat and liver fat in people with HIV, which led to its approval in the US as Egrifta. This article explains what tesamorelin is, what those trials found, its side effects and where it stands in the UK and in sport. It describes published research only; there is no licensed use in the UK, and ALTA PEPTIDES supplies tesamorelin for laboratory research only.
- Tesamorelin is a synthetic version of the full 44-amino-acid human growth hormone-releasing hormone (GHRH), with a trans-3-hexenoyl group added to the first amino acid to make it last longer in the body.
- It acts on GHRH receptors in the pituitary, which then releases the body's own growth hormone in its normal pulses; IGF-1 rose 81% in the first trial.
- The FDA approved it as Egrifta on 10 November 2010 to reduce excess abdominal fat in adults with HIV and lipodystrophy. It is not authorised in the UK or EU.
- In the 2007 NEJM trial, deep abdominal (visceral) fat fell 15.2% over 26 weeks with tesamorelin against a 5.0% rise on placebo; the fat came back after treatment stopped.
- In a 2019 Lancet HIV trial, liver fat fell by a relative 37% compared with placebo over 12 months.
- WADA prohibits GHRH and its analogues, including tesamorelin, at all times under S2.
What does tesamorelin do?
In shortIt tells the pituitary to release more of the body's own growth hormone.
- 01Tesamorelin
A protected copy of GHRH
- 02Pituitary
GHRH receptors switched on
- 03Growth hormone
Released in natural pulses
- 04Liver
Makes more IGF-1 (+81% in the trial)
Falutz et al., NEJM 2007; Egrifta US prescribing information.
It acts on GHRH receptors in the pituitary gland, just as the body's own GHRH does. The pituitary responds by releasing growth hormone in its normal pattern of pulses, and the liver then makes more IGF-1, the hormone that carries many of growth hormone's effects. In the first large trial, IGF-1 rose by 81% on tesamorelin. Natural GHRH is broken down within minutes, so tesamorelin carries a small chemical change, a trans-3-hexenoyl group on its first amino acid, that protects it from the enzyme that would otherwise cut it.
Is tesamorelin the same as growth hormone?
In shortNo. It's the signal, not the hormone, so natural pulses and feedback stay.
Swipe the table to compare →
| Tesamorelin | Growth hormone | Ipamorelin | |
|---|---|---|---|
| What it is | GHRH copy (signal) | The hormone itself | Ghrelin-receptor agonist |
| Body's own GH pulses | Kept | Bypassed | Kept |
| Large human trials | Yes | Yes | No |
| Licensed | US only, HIV | Yes, UK and worldwide | Nowhere |
From this article.
No, and the difference matters. Growth hormone itself (somatropin) is the end product. Tesamorelin works one step earlier: it is the signal, and the pituitary decides how much growth hormone to release. Because the body's feedback loops stay in place, growth hormone still comes in pulses rather than as a flat high level. Other peptides work at the same step or a nearby one: sermorelin is a shorter piece of GHRH, CJC-1295 is a longer-lasting GHRH analogue, and ipamorelin works through a different receptor, the ghrelin receptor. Of these, tesamorelin is the one with the largest human trials and a licensed product.
What is tesamorelin approved for?
In shortIn the US only, for excess belly fat in people with HIV and lipodystrophy.
The FDA approved Theratechnologies' Egrifta on 10 November 2010 to reduce excess abdominal fat in adults with HIV who have lipodystrophy, a change in body fat linked to some HIV treatments. A single-vial version (later called Egrifta SV) was approved in November 2018, and a newer formulation, Egrifta WR, was approved in March 2025 and replaces it. The approval is narrow: the label says it is not for weight loss, and its long-term effect on heart health has not been studied.
Does tesamorelin reduce belly fat?
In shortIn trials, deep belly fat fell about 15% in six months, then returned after stopping.
In the extension phases.
Percent fall in visceral fat. Falutz et al., NEJM 2007 and JAIDS 2010.
In its approved group, yes. The first phase 3 trial, published in the New England Journal of Medicine in 2007, treated 412 people with HIV and abdominal fat build-up for 26 weeks. Visceral fat, the deep fat around the organs, fell by 15.2% on tesamorelin while it rose by 5.0% on placebo. Triglycerides improved, and there was no significant change in blood-sugar measures in that trial. A second phase 3 trial found a 10.9% fall against 0.6%, and a pooled analysis of 806 people put the treatment effect at about 15% at 26 weeks. Fat under the skin changed little, which is part of why it attracted interest: it targeted the fat most linked with health risk. The catch is that it does not last. People switched to placebo in the extension phases regained the visceral fat.
What about liver fat?
In shortA 2019 trial cut liver fat by over a third compared with placebo.
HIV with fatty liver.
Relative to placebo.
Tesamorelin vs placebo.
Stanley et al., Lancet HIV 2019.
Fatty liver is common in people with HIV, and visceral fat and liver fat tend to go together, so researchers tested tesamorelin on the liver. In a randomised trial published in The Lancet HIV in 2019, 61 people with HIV and non-alcoholic fatty liver disease received tesamorelin or placebo for 12 months. Liver fat fell by 4.1 percentage points more on tesamorelin, a relative reduction of 37%, and 35% of the tesamorelin group reached a normal liver fat level against 4% on placebo, with no difference in glucose or HbA1c. It is one of the reasons tesamorelin is still studied, though it is not approved for liver disease.
What are the side effects of tesamorelin?
In shortJoint pain, injection-site reactions, swelling, and possible raised blood sugar.
The US label lists the most common adverse reactions as joint pain, redness and itching at the injection site, pain in the arms or legs, swelling of the hands and feet, and muscle pain; injection-site reactions were reported by 25% of people on tesamorelin against 14% on placebo. Because it raises growth hormone and IGF-1, the label also warns about fluid retention, raised blood sugar and the risk of developing diabetes, raised IGF-1 levels and allergic reactions. It must not be used in pregnancy, or by anyone whose pituitary has been removed or damaged, for example by surgery, a tumour, radiation to the head or head injury.
Is tesamorelin legal, and is it banned in sport?
In shortNot controlled, not licensed in the UK, banned for athletes.
EU application withdrawn, 2012.
Egrifta, HIV lipodystrophy.
S2, at all times.
From this article.
In the UK, tesamorelin is not a controlled drug. It has no UK marketing authorisation, and it has never been authorised in the EU: Ferrer withdrew the European application in June 2012, when the European Medicines Agency's committee considered that the benefits did not outweigh the risks, mainly because long-term safety data were lacking. It can be bought and held as a laboratory reagent; supplying it for human use is an offence under the Human Medicines Regulations 2012, as our guide to peptides and UK law explains. In sport, WADA prohibits growth hormone-releasing factors, including GHRH and its analogues such as tesamorelin, at all times under section S2.
Everything above is the quick version. The sections below go deeper.
Where tesamorelin comes from
In shortDeveloped in Montreal from the full natural GHRH chain, with one protective change.
- 1982GHRH identified
The 44-amino-acid natural hormone.
- 2007First phase 3 trial
NEJM: deep belly fat down 15%.
- 2010Egrifta approved
US, HIV lipodystrophy.
- 2012EU application withdrawn
Long-term safety data lacking.
- 2019Liver fat trial
Lancet HIV.
- 2025Egrifta WR
New US formulation.
Sources in this article.
Tesamorelin was developed by Theratechnologies in Montreal under the code TH9507. GHRH itself was identified in the early 1980s, and its full natural form is 44 amino acids long. Theratechnologies kept the whole sequence and added the hexenoyl group to the front end to stop the enzyme dipeptidyl peptidase-4 from clipping it, which is what makes natural GHRH so short-lived. The phase 3 programme in HIV lipodystrophy led to the 2010 US approval.
Tesamorelin and memory research
In shortOne 20-week trial in older adults found better planning and mental flexibility.
Because growth hormone and IGF-1 fall with age, researchers have asked whether raising them affects the ageing brain. In a 20-week randomised trial published in Archives of Neurology in 2012, 152 adults aged 55 to 87, some healthy and some with mild cognitive impairment, received tesamorelin or placebo. The tesamorelin group did better on tests of executive function (planning and mental flexibility), with a trend towards better verbal memory. It was a single, short trial, and it has not led to any approved use.
In the laboratory
In shortSupplied as tested powder in sealed vials. Keep it cold and use solutions within two weeks.
Tesamorelin is supplied by ALTA PEPTIDES as a freeze-dried powder in sealed vials, purity 99% or better by , with the certificate for each lot published. It is a large peptide: formula C221H366N72O67S, mass about 5135.9 g/mol, CAS 218949-48-5. Keep sealed vials at 2 to 8 °C away from light, and note that reconstituted solutions should be used within two weeks; our guides to storage and reconstitution cover handling, and the peptide calculator does the solution arithmetic. Research use only, under our research use policy.
Sources
- Falutz J, Allas S, Blot K, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. New England Journal of Medicine 2007;357:2359-2370. PMID 18057338.
- Falutz J, Potvin D, Mamputu JC, 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. Journal of Acquired Immune Deficiency Syndromes 2010;53(3):311-322.
- Falutz J, Mamputu JC, Potvin D, et al. Effects of tesamorelin on visceral adipose tissue in HIV-infected patients with excess abdominal fat: a pooled analysis of two multicenter, double-blind placebo-controlled phase 3 trials with safety extension data. Journal of Clinical Endocrinology & Metabolism 2010;95(9):4291-4304. PMID 20554713.
- 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.
- 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. Archives of Neurology 2012;69(11):1420-1429. PMID 22869065.
- US Food and Drug Administration. EGRIFTA SV (tesamorelin for injection) prescribing information; Theratechnologies press releases on approval, 10 November 2010, 5 November 2018 and 25 March 2025.
- European Medicines Agency. Questions and answers on the withdrawal of the marketing authorisation application for Egrifta (tesamorelin), 2012.
- World Anti-Doping Agency. Prohibited List, section S2 (peptide hormones, growth factors, related substances and mimetics).
Questions people ask
Is tesamorelin the same as growth hormone?
No. Tesamorelin is a copy of the brain signal (GHRH) that tells the pituitary to release growth hormone. The pituitary then releases the body's own growth hormone, in pulses, and its normal feedback controls stay in place.
Does tesamorelin reduce belly fat?
In trials in people with HIV and lipodystrophy, it reduced deep abdominal (visceral) fat by about 15% compared with placebo over six months. The fat returned after it was stopped. It has not been approved for fat loss in anyone else.
What are the side effects of tesamorelin?
The US label lists joint pain, redness and itching at the injection site, pain in the arms or legs, swelling and muscle pain as the most common. It can raise blood sugar and IGF-1, and it must not be used in pregnancy.
Is tesamorelin legal in the UK?
It is not a controlled drug, and it has no UK marketing authorisation, so it can be bought and held as a laboratory reagent. Supplying it for human use is an offence under the Human Medicines Regulations 2012. It is banned in sport under WADA's S2.
Information, not advice. This article summarises published research; nothing here is guidance on human or veterinary use. Products are sold under our research use policy.
