Tesamorelin

Tesamorelin is a stabilized synthetic analogue of human growth hormone releasing hormone. It is FDA-approved as Egrifta for reducing excess abdominal fat in adults with HIV-associated lipodystrophy.

Last reviewed 2026-10-25 by the PeptideWiki editorial team. Editorial policy.

Overview

Tesamorelin is a synthetic version of the full 44-amino-acid human growth hormone releasing hormone (GHRH) with an added fatty acyl group at the N-terminus. The modification protects the peptide from rapid enzymatic breakdown while preserving its activity at the GHRH receptor. It was developed by the Canadian company Theratechnologies under the code TH9507. The full-length backbone distinguishes it from GRF(1-29)-based analogues, which use only the first 29 residues of the hormone.

Tesamorelin is FDA-approved as Egrifta for the reduction of excess abdominal fat in people with HIV who have lipodystrophy. The approval was based on randomized, placebo-controlled phase 3 trials that measured visceral adipose tissue by imaging. It is the only GHRH analogue currently marketed in the US and is a reference compound for research on the growth hormone axis, visceral fat and liver fat.

Compare: Sermorelin vs Tesamorelin.

Structure

Tesamorelin is the complete 44-residue human GHRH sequence with a C-terminal amide and a trans-3-hexenoyl group attached to the N-terminal tyrosine. The N-terminal modification hinders cleavage by dipeptidyl peptidase-4, which otherwise rapidly inactivates native GHRH. Unlike shorter analogues such as sermorelin or CJC-1295, it retains the full natural sequence rather than amino acid substitutions. The drug product is formulated as the acetate salt.

Mechanism

Tesamorelin acts as an agonist at the GHRH receptor on anterior pituitary somatotrophs. Receptor activation increases cyclic AMP signaling and stimulates synthesis and pulsatile release of endogenous growth hormone, which raises circulating IGF-1. Because it works through the pituitary, release remains subject to physiological regulation by somatostatin and IGF-1 feedback.

Growth hormone promotes lipolysis, particularly in visceral adipose tissue, which is the proposed basis for the reductions in abdominal visceral fat observed in clinical trials. Effects on liver fat and other metabolic measures are thought to follow from the same growth hormone and IGF-1 signaling, though the full mechanism is not completely defined.

Research

HIV-associated abdominal fat

In randomized, placebo-controlled phase 3 trials in adults with HIV and excess abdominal fat, tesamorelin reduced visceral adipose tissue measured by CT compared with placebo, meeting the primary endpoint. Subcutaneous fat was largely unchanged. Trials also reported increases in IGF-1 and monitored glucose parameters. These results supported FDA approval of Egrifta and are the principal human efficacy data for the compound.

Liver fat in people with HIV

Later randomized studies examined tesamorelin in people with HIV and nonalcoholic fatty liver disease, using imaging and biopsy-based measures of liver fat and fibrosis. These studies reported reductions in liver fat relative to placebo. The evidence base is smaller than for the approved indication, and liver outcomes are not part of the approved labeling. Further work would be needed to establish clinical relevance.

Growth hormone axis research

Because tesamorelin stimulates endogenous growth hormone rather than replacing it, it has been used to study the physiology of the somatotropic axis, including effects on body composition, lipids and glucose metabolism. Small studies have also explored cognitive endpoints in older adults. These exploratory findings are limited and do not establish benefits outside the approved indication. Human studies outside HIV populations have generally been small and short.

Regulatory status

Tesamorelin is FDA-approved as Egrifta (Theratechnologies) for the reduction of excess abdominal fat in adults with HIV-associated lipodystrophy. As an approved drug product, compounded versions are subject to FDA restrictions on copying approved drugs; check current FDA guidance. GHRH analogues are prohibited at all times under section S2 of the WADA Prohibited List.

Status changes often. See the regulatory tracker for dated updates.

Quality and identity testing

A COA should confirm identity by mass spectrometry, with the observed mass matching the expected mass shown on this page, and report purity by reverse-phase HPLC. The N-terminal trans-3-hexenoyl group must be present: material lacking it is native GHRH(1-44), and cis/trans isomers of the acyl group may also need to be distinguished. As a 44-residue peptide containing methionine and asparagine, tesamorelin is prone to oxidation, deamidation and deletion impurities from synthesis, and it can aggregate. Counter-ion (acetate) and net peptide content should be stated.

For a walkthrough of each section of a certificate, see how to read a COA.

Storage and stability

Store lyophilized tesamorelin sealed and protected from light; for research material, -20 °C is the standard long-term condition, and vials should equilibrate to room temperature before opening. In solution the peptide is susceptible to methionine oxidation, deamidation and aggregation, so reconstituted laboratory material should be refrigerated, used promptly and not shaken vigorously. Aliquot to avoid repeated freeze-thaw cycles. Approved drug product should be stored according to its labeling.

Download the Tesamorelin data sheet (PDF): sequence, masses, expected MS ions and handling on one printable page.

Latest research

Frequently asked questions

Related compounds

• Sermorelin

  Sermorelin is a synthetic peptide consisting of the first 29 amino acids of human growth hormone releasing hormone (GHRH). It was previously FDA-approved as Geref but has been discontinued in the US.

• CJC-1295

  CJC-1295 is a synthetic analogue of growth hormone releasing hormone (GHRH). The name properly refers to a version with a drug affinity complex (DAC) that binds albumin, but is also applied to modified GRF(1-29), which lacks DAC.

• Ipamorelin

  Ipamorelin is a synthetic pentapeptide growth hormone secretagogue that acts as a selective agonist of the ghrelin receptor (GHS-R1a). It is investigational and not approved for any use.

• IGF-1 LR3

  IGF-1 LR3 is a recombinant analogue of insulin-like growth factor 1 with an arginine substitution at position 3 and a 13-residue N-terminal extension. It binds IGF-binding proteins weakly and is widely used in cell culture.

References

1. 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. Find on PubMed
2. PubMed: all indexed literature on Tesamorelin
3. ClinicalTrials.gov: registered studies mentioning Tesamorelin