Tesamorelin: what the molecule is, what the clinical trials measured, and what its FDA label and COA say

What tesamorelin is: a stabilized, full-length GHRH analogue#

Tesamorelin is a synthetic analogue of human growth hormone-releasing hormone (GHRH, also written GRF), the 44-amino-acid hypothalamic peptide that signals the pituitary to make and release growth hormone. Tesamorelin keeps the full 44-residue sequence of human GHRH and adds a trans-3-hexenoyl group, a six-carbon chain with one double bond, to the N-terminal tyrosine ^[1]. That modification makes the molecule more resistant to the enzyme that rapidly breaks down natural GHRH in the body. Its development code was TH9507.

Identifiers: molecular formula C221H366N72O67S (free base), molecular weight 5,135.9 Da, CAS registry number 901758-09-6 for the acetate salt ^[1][2]. The sequence runs Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-Gln-Gln-Gly-Glu-Ser-Asn-Gln-Glu-Arg-Gly-Ala-Arg-Ala-Arg-Leu, amidated at the C-terminus ^[2]. At 44 residues it is one of the larger peptides in a typical research catalog.

The closest comparison is sermorelin, which contains only the first 29 amino acids of GHRH, the shortest fragment that retains full activity at the receptor. Tesamorelin is the whole hormone with a stabilizing group; sermorelin is the active fragment without one. CJC-1295 is a third GHRH-derived molecule, covered in our CJC-1295 explainer.

Tesamorelin's regulatory status: Egrifta and its label#

FDA approved tesamorelin in 2010 under the brand name Egrifta, developed by Theratechnologies. Later formulations, Egrifta SV and Egrifta WR, carry the same single indication. The March 2025 label states that the product "is indicated for the reduction of excess abdominal fat in HIV-infected adult patients with lipodystrophy" ^[1]. Lipodystrophy here means the change in body-fat distribution associated with HIV and the medicines used to control it.

The label's limitations of use matter for anyone reading about this peptide. It states that long-term cardiovascular safety has not been established, and that the product is not indicated for managing body weight because its effect on weight is neutral ^[1]. The label also lists contraindications (disruption of the hypothalamic-pituitary axis, active malignancy, hypersensitivity, pregnancy) and warnings covering neoplasms, elevated IGF-1, fluid retention, glucose intolerance, hypersensitivity and local reactions at the site of administration ^[1]. These are the findings of a regulator reviewing a drug product; they are listed here as part of the compound's documented record, not as guidance of any kind.

Mechanism, as described by the regulator#

The label's mechanism section is brief and specific. In laboratory assays tesamorelin binds and stimulates human GRF receptors with potency similar to the natural hormone. GRF acts on the pituitary's somatotroph cells to stimulate the synthesis and pulsatile release of endogenous growth hormone, which in turn raises IGF-1, the growth factor produced mainly by the liver ^[1]. In the trials below, the rise in IGF-1 was the direct marker that the peptide was acting on this axis.

What the clinical trials measured#

Unlike most peptides sold for research, tesamorelin has a body of randomized, placebo-controlled human trials, because it went through drug development. All of the major trials enrolled adults with HIV. Here is what each one measured and found; our guide to reading published peptide research explains the study types.

The two registration trials#

The 2007 New England Journal of Medicine trial randomized 412 adults with HIV and excess abdominal fat to tesamorelin or placebo for 26 weeks. Visceral adipose tissue, measured by CT, decreased 15.2% in the tesamorelin group and increased 5.0% in the placebo group; IGF-1 rose 81% with tesamorelin and fell 5% with placebo. More participants in the tesamorelin group withdrew because of adverse events ^[3]. The 2010 trial in JAIDS enrolled 404 adults in the same population for a 6-month comparison followed by a 6-month extension. VAT fell 10.9% with tesamorelin against 0.6% with placebo. In the extension, participants who continued for 12 months reached about an 18% reduction, while those re-randomized to placebo lost the earlier change quickly ^[4]. Together these two trials were the basis of the 2010 approval.

The liver-fat trials#

Two later trials from the Massachusetts General Hospital group asked whether the same peptide changed liver fat in people with HIV. The 2014 JAMA trial (50 participants, 6 months) found a modest but statistically significant decrease in the liver's lipid-to-water fraction alongside the expected change in visceral fat ^[5]. The 2019 Lancet HIV trial (61 participants, 12 months) enrolled people with HIV whose hepatic fat fraction was at least 5%. The absolute difference in hepatic fat fraction between tesamorelin and placebo was −4.1 percentage points, and 35% of the tesamorelin group versus 4% of the placebo group ended below the 5% threshold. Fasting glucose and glycated hemoglobin did not differ between groups ^[6]. The authors wrote that further studies were needed to determine long-term effects on liver histology. Liver fat is not an approved indication.

What the research does not cover#

• People without HIV. Every major randomized trial enrolled adults with HIV, so the findings describe that population.
• Long-term cardiovascular outcomes. The label says this has not been established ^[1].
• Durability. In the 2010 extension, the change in visceral fat reversed when the peptide was stopped ^[4].
• Any effect in cell or animal systems beyond receptor binding. Tesamorelin's literature is clinical, not preclinical; the in-vitro receptor data come from the label.
• Comparisons with sermorelin or CJC-1295 in the same study. The three GHRH-derived peptides have separate literatures.

Anti-doping status#

The 2026 WADA Prohibited List names tesamorelin, with CJC-1293, CJC-1295 and sermorelin, as a GHRH analogue under section S2.2.4, growth hormone releasing factors. The same section lists growth hormone secretagogues such as ipamorelin. Section S2 is prohibited at all times, in and out of competition ^[7]. Anyone handling this material in a sport context should be aware of that listing.

Reading a tesamorelin Certificate of Analysis#

Renuvia's October 2026 lot, RN-2610-TESA, was tested by Freedom Diagnostics Testing. The report gives an HPLC-UV purity of 99.13%, confirms identity by LC-MS, and measures 5.25 mg of peptide in a vial labeled 5 mg, which is 105% of label ^[8]. The report is in the COA library. When you read any tesamorelin COA, check these points:

1. The mass spectrometry result should match the full-length, hexenoyl-modified molecule (about 5,136 Da for the free base), not the mass of unmodified GHRH or of a shorter fragment such as sermorelin.
2. The measured content, in milligrams, should be stated separately from the purity percentage. Purity says how clean the peptide is; content says how much is in the vial. Our peptide purity guide explains why the two are often confused.
3. The lot number on the report should match the vial, and the laboratory should be named with a report or accession number you can check.
4. Because tesamorelin is a 44-residue peptide, the chromatogram may show small adjacent peaks from deletion or oxidation products. The report should quantify them rather than hide them in a single rounded figure.

The guides to reading a Certificate of Analysis and to HPLC and mass spectrometry walk through each section of a report.