What is tesamorelin and how does it differ from growth hormone?

Tesamorelin is a synthetic, stabilized analog of GHRH, the hormone that tells the pituitary to release growth hormone. It is not growth hormone: instead of introducing hormone from outside, it stimulates the body to produce its own in a pulsatile way, which in turn raises IGF-1. This is educational information, not medical advice.

What exactly was tesamorelin approved for?

The FDA approved it (Egrifta and its versions) solely to reduce excess abdominal fat in adults with HIV-associated lipodystrophy, backed by Phase III trials. It is not approved for any other use, and in the EU and the UK it is not approved at all after the EMA application was withdrawn in 2012. The effects reverse once it is stopped.

Is it legal to use tesamorelin for other things?

In its approved indication it is a prescription drug dispensed by prescription under medical supervision. Outside that indication it is not backed by any regulator, and material sold as a 'research peptide' outside licensed pharmacy channels should be treated as Research Use Only, with no quality guarantees or clinical cover. This guide is not medical advice.

← Guides

Tesamorelin: what it is and what it was approved for

Tesamorelin is an unusual case among the peptides studied in this field: unlike most of them, it is a genuinely approved prescription drug backed by Phase III clinical trials. But that approval is for a very specific indication, and everything outside it is a different story. This guide summarizes, at an educational level, what the molecule is, how it acts, exactly what it was approved for and why material circulating outside licensed pharmacy channels should be treated as a research substance. It is not medical advice or a recommendation for use, and it contains no doses or protocols. If it interests you for health reasons, consult a healthcare professional.

What tesamorelin is

Tesamorelin is a synthetic analog of growth hormone-releasing hormone (GHRH). Specifically, it reproduces human GHRH 1-44 but with a modification at the N-terminus that stabilizes it and makes it more resistant to enzymatic degradation, so it lasts longer and acts in a more sustained way than natural GHRH. It is a laboratory-made molecule, not a biological extract, and is also referred to by its development code TH9507 or its brand name, Egrifta. It is worth distinguishing it from growth hormone itself from the outset: tesamorelin is not growth hormone but a signal that asks the pituitary to release its own. The campus tesamorelin profile lists its name, synonyms and reference mechanism.

How it acts

Tesamorelin binds to the GHRH receptors on somatotrophs, the anterior-pituitary cells responsible for producing growth hormone. By stimulating those receptors, it promotes the pulsatile, physiologic-pattern release of endogenous growth hormone — the body's own — rather than introducing hormone from outside. That rise in growth hormone in turn raises IGF-1 and shifts fat metabolism toward reduction of visceral adipose tissue, the deep fat surrounding the abdominal organs. The idea of preserving a secretion pattern closer to the natural one is, in theory, what distinguishes this approach from giving growth hormone directly, though the clinical outcome depends on the indication and the medical context.

What it was approved for

Tesamorelin is one of the few peptides in this class with genuine Phase III randomized, placebo-controlled trial support. The US FDA approved it (under the brands Egrifta, Egrifta SV and Egrifta WR) for a single, tightly defined indication: reduction of excess abdominal fat in adults with HIV-associated lipodystrophy, a fat-redistribution disorder linked to the infection or to some antiretroviral treatments. In the trials, run in hundreds of patients, visceral fat fell by roughly 15-18% versus placebo at 26 weeks, with an extension confirming durability of the effect. Three caveats matter: the approval is for that indication only and no other; the effects reverse once treatment stops; and in the EU and the UK it is not approved, because the manufacturer withdrew its EMA application in 2012 after the CHMP concluded a positive benefit-risk balance had not been established.

Off-label use and grey-market material

Precisely because it stimulates the GH/IGF-1 axis, tesamorelin draws interest outside its approved indication — for instance around body composition or visceral fat in the general population — but that use is not backed by any regulator and has no trials establishing its safety or efficacy in those contexts. The key distinction is between two very different things: the approved drug, dispensed by prescription through a licensed pharmacy under medical supervision; and material sold as a 'research peptide' outside those channels, which should be treated as Research Use Only (RUO). The latter carries no guarantees of identity, purity or dosing, and its use falls outside any clinical or legal cover. An independent third-party CoA is the minimum bar for RUO material, but a certificate does not turn an unapproved substance into a treatment. Moreover, because it raises endogenous GH/IGF-1, there is a class warning against its use in the presence of active or suspected malignancy, among other precautions.

Frequently asked questions

What is tesamorelin and how does it differ from growth hormone?: Tesamorelin is a synthetic, stabilized analog of GHRH, the hormone that tells the pituitary to release growth hormone. It is not growth hormone: instead of introducing hormone from outside, it stimulates the body to produce its own in a pulsatile way, which in turn raises IGF-1. This is educational information, not medical advice.
What exactly was tesamorelin approved for?: The FDA approved it (Egrifta and its versions) solely to reduce excess abdominal fat in adults with HIV-associated lipodystrophy, backed by Phase III trials. It is not approved for any other use, and in the EU and the UK it is not approved at all after the EMA application was withdrawn in 2012. The effects reverse once it is stopped.
Is it legal to use tesamorelin for other things?: In its approved indication it is a prescription drug dispensed by prescription under medical supervision. Outside that indication it is not backed by any regulator, and material sold as a 'research peptide' outside licensed pharmacy channels should be treated as Research Use Only, with no quality guarantees or clinical cover. This guide is not medical advice.

✓ Last reviewed · 2026-07-24