What Is Tesamorelin? The Full-Length GHRH Analogue

Tesamorelin is a synthetic analogue of growth hormone-releasing hormone (GHRH). Unlike sermorelin and CJC-1295, which use only the first 29 residues, tesamorelin keeps all 44 amino acids of human GHRH and adds a trans-3-hexenoyl group to the N-terminus to block enzymatic cleavage. It is the GHRH analogue with the most clinical data, built around a specific licensed indication.

For laboratory research use only. The compounds discussed are not approved for human or veterinary use and are not drugs, foods or cosmetics. This article summarises published research and is not medical advice.

Key points

Full-length GHRH(1-44) with an N-terminal trans-3-hexenoyl modification.
C₂₂₁H₃₆₆N₇₂O₆₇S, ~5136 g/mol.
Acts on the pituitary GHRH receptor to stimulate endogenous GH release.
Licensed in the US for HIV-associated abdominal fat accumulation.
Not a GLP-1 agonist, despite frequent online confusion.

Quick facts

Property	Value
Sequence basis	Human GHRH(1-44)-NH₂
Modification	trans-3-hexenoyl on Tyr1
Formula / weight	C₂₂₁H₃₆₆N₇₂O₆₇S, ~5136 g/mol (PubChem CID 16137828)
Receptor	GHRH receptor (pituitary somatotrophs)
Downstream marker	IGF-I
Regulatory status	Licensed for a specific indication (US)

Our tesamorelin research peptide is supplied in 5, 10 and 20 mg vials with lot-level HPLC and MS data.

How it works

The GHRH receptor is a G-protein-coupled receptor on pituitary somatotrophs; activation raises cAMP and drives GH synthesis and release (Halmos et al., 2025). Tesamorelin stimulates the body’s own GH secretion rather than supplying GH directly, so pituitary feedback mechanisms remain in place. Native GHRH is rapidly inactivated by dipeptidyl peptidase-4, which removes the first two residues. The hexenoyl cap on tyrosine 1 is designed to prevent this.

Analogue	Length	Protection strategy
Sermorelin	1–29	None (native sequence, amidated)
CJC-1295 (no DAC)	1–29	Four amino acid substitutions
CJC-1295 with DAC	1–29 + linker	Substitutions + albumin binding
Tesamorelin	1–44	N-terminal trans-3-hexenoyl group

Clinical trial endpoints

In a phase 3 trial, 412 people with HIV and abdominal fat accumulation (86% men) were randomised to daily tesamorelin or placebo for 26 weeks. The primary endpoint was the percentage change in visceral adipose tissue measured by CT (Falutz et al., 2007).

Endpoint (26 weeks)	Tesamorelin	Placebo
Visceral adipose tissue	−15.2%	+5.0%
Triglycerides	−50 mg/dL	+9 mg/dL
Total : HDL cholesterol ratio	−0.31	+0.21
IGF-I	+81.0%	−5.0%

A 2011 review of two 26-week phase 3 trials found that tesamorelin reduced visceral but not subcutaneous adipose tissue to a clinically significant extent. The reduction was maintained to week 52 in participants who continued, but visceral fat re-accumulated after discontinuation. Serious treatment-emergent adverse events occurred in fewer than 4% of patients (Dhillon, 2011). These are results in a defined patient population under medical supervision and do not apply to research material.

Detection

GHRH analogues are prohibited in sport. An LC-MS/MS method covering tesamorelin, sermorelin and both forms of CJC-1295, together with 19 synthesised in vitro metabolites, achieved detection limits generally at or below 1 ng/mL in urine (Memdouh et al., 2021).

Handling in the lab

Store lyophilized powder at −20 °C (2–8 °C short-term), sealed and dark.
At 44 residues, tesamorelin is larger than most research peptides; dissolve with gentle swirling and allow extra time.
Reconstituted solutions: 2–8 °C, protected from light; avoid freeze–thaw (storage guide).
Tesamorelin contains a methionine (Met27), so minimise air and light exposure to limit oxidation (+16 Da by MS).
Use the peptide reconstitution calculator; method in how to reconstitute peptides.

Tesamorelin in the GHRH analogue family

For researchers, tesamorelin is the GHRH analogue closest to the natural hormone in sequence. That makes it a useful reference when comparing shorter analogues such as sermorelin or CJC-1295, whose behaviour differs because of their length, substitutions or albumin binding. When interpreting IGF-I changes, remember that IGF-I reflects integrated GH exposure over days, not the immediate GH response to a single exposure.

Open questions

Why does tesamorelin preferentially reduce visceral rather than subcutaneous fat in the trials? Depot-specific GH sensitivity is one hypothesis.
How do outcomes differ outside the HIV-associated lipodystrophy population in which it was licensed?

Related research

Frequently asked questions

What is tesamorelin?

Tesamorelin is a synthetic analogue of human growth hormone-releasing hormone (GHRH). It consists of all 44 amino acids of GHRH with a trans-3-hexenoyl group attached to the N-terminal tyrosine, which protects it from enzymatic cleavage.

Is tesamorelin a peptide?

Yes. It is a 44-residue peptide with a molecular weight of about 5136 g/mol (C221H366N72O67S).

Is tesamorelin a GLP-1 agonist?

No. Tesamorelin acts on the GHRH receptor in the pituitary to stimulate growth hormone release. It is unrelated to GLP-1 receptor agonists such as semaglutide or tirzepatide.

What is tesamorelin approved for?

It was approved in the US for reducing excess abdominal fat in people with HIV-associated lipodystrophy, based on two 26-week phase 3 trials.

Does tesamorelin need to be refrigerated?

Lyophilized research material is best stored at −20 °C long-term and 2–8 °C short-term; reconstituted solutions should be kept at 2–8 °C and protected from light.

References

Falutz J, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med. 2007. PMID: 18057338 https://pubmed.ncbi.nlm.nih.gov/18057338/
Dhillon S. Tesamorelin: a review of its use in the management of HIV-associated lipodystrophy. Drugs. 2011. PMID: 21668043 https://pubmed.ncbi.nlm.nih.gov/21668043/
Memdouh S, et al. Advances in the detection of growth hormone releasing hormone synthetic analogs. Drug Test Anal. 2021. PMID: 34665524 https://pubmed.ncbi.nlm.nih.gov/34665524/
Halmos G, et al. Growth hormone-releasing hormone receptor (GHRH-R) and its signaling. Rev Endocr Metab Disord. 2025. PMID: 39934495 https://pubmed.ncbi.nlm.nih.gov/39934495/
PubChem Compound Summary for CID 16137828, Tesamorelin. National Center for Biotechnology Information. https://pubchem.ncbi.nlm.nih.gov/compound/16137828