Tesamorelin is a synthetic analog of human growth hormone-releasing hormone (GHRH) that keeps all 44 amino acids of the native hormone and adds one small chemical group: a trans-3-hexenoyl cap on the N-terminal tyrosine. Developed by the Canadian company Theratechnologies under the code TH9507, it is one of the few GHRH analogs that reached approval as a drug product.
For laboratory work, its interest lies in that design choice. Most synthetic GHRH analogs use the shortened 1-29 fragment, while tesamorelin keeps the full-length chain and protects it at a single site. This article covers its origin, structure, receptor pharmacology, the non-clinical studies that characterized it, and what its literature does and does not support.
At a glance
- Class: Synthetic GHRH(1-44) analog peptide; GHRH receptor agonist
- Origin: Theratechnologies (code TH9507); non-clinical profile published by Ferdinandi and colleagues in 2007
- Structure: 44 residues of human GHRH with an N-terminal trans-3-hexenoyl group and C-terminal amide; C221H366N72O67S; 5136.0 g/mol; CAS 218949-48-5
- Main research areas: GHRH receptor pharmacology, N-terminal stabilization, GH/IGF-1 axis and adipose tissue biology, analytical detection
- Regulatory status: A tesamorelin drug product is FDA approved (2010) for one specific indication; WADA S2
Structure and origin
Human GHRH is a 44-residue amidated peptide whose hypothalamic structure was established by Ling and colleagues in 1984 (Ling et al., 1984). Native GHRH is broken down within minutes in plasma. The main route is cleavage of the Tyr1-Ala2 dipeptide by dipeptidyl peptidase-4, which leaves an inactive GHRH(3-44).
Two broad strategies emerged to address this. One shortens the peptide to residues 1-29 and replaces vulnerable amino acids, the route taken by sermorelin derivatives and CJC-1295. The other, used for tesamorelin, leaves the sequence untouched and blocks the N-terminus chemically. A trans-3-hexenoic acid is attached to the amino group of Tyr1, forming an amide. The six-carbon unsaturated acyl group hinders aminopeptidase access while leaving the receptor-binding residues in place.
Keeping residues 30-44 makes tesamorelin the closest stabilized analog of full-length GHRH available. Whether that C-terminal region contributes meaningfully to receptor binding, stability or tissue distribution, compared with 1-29 analogs, is one of the questions the molecule allows researchers to ask.
Mechanism: what the research shows
Tesamorelin acts at the GHRH receptor, a class B G protein-coupled receptor cloned from pituitary tissue in 1992 (Mayo, 1992). Activation couples to Gs, adenylate cyclase and cAMP, which drives GH synthesis and release from anterior pituitary somatotrophs and supports somatotroph proliferation (Mayo et al., 2000). The GH that is released then acts on the liver and other tissues to raise IGF-1.
The non-clinical program reported by Ferdinandi and colleagues characterized TH9507 in rats and dogs. The studies compared its GH-releasing activity with native human GHRH, examined its stability, and covered safety pharmacology and toxicology (Ferdinandi et al., 2007). Because the analog works upstream of GH, its effects remain subject to normal feedback, including somatostatin inhibition and IGF-1 negative feedback, a point often noted when contrasting GHRH analogs with direct administration of GH in experimental settings.
Key areas of study
Non-clinical pharmacology and safety
The 2007 paper remains the main published preclinical description of the molecule. It reported GH responses in rats and dogs and documented a toxicology profile in both species (Ferdinandi et al., 2007). For researchers, it is the reference point for species differences and for how the hexenoyl cap affects activity relative to unmodified GHRH.
GHRH receptor signaling
As a full-length agonist, tesamorelin is a useful comparator in receptor assays alongside sermorelin and other 1-29 analogs. The receptor expression systems that make these comparisons possible trace back to the cloning work (Mayo, 1992).
GH/IGF-1 axis and adipose tissue
Most published work on tesamorelin concerns its effect on the GH axis and on fat distribution, particularly visceral adipose tissue. A 2011 drug review summarizes the pharmacology and clinical development program in HIV-associated lipodystrophy (Dhillon, 2011), and a randomized placebo-controlled trial with a safety extension was published in 2010 (Falutz et al., 2010). These studies are cited here for regulatory and historical context.
Analytical detection
Because GHRH analogs are prohibited in sport, the hexenoyl-modified peptide and its metabolites are targets for mass spectrometry methods in anti-doping laboratories. The N-terminal cap gives the molecule a distinctive mass signature compared with native GHRH.
What the evidence does not show
- Published preclinical data come largely from the developer’s own program; independent preclinical studies are relatively few.
- The clinical literature concerns one approved indication in one population. It does not establish effects in other settings, and those findings describe a regulated drug product, not research-grade material.
- Direct comparisons between full-length tesamorelin and stabilized 1-29 analogs under identical conditions are scarce, so the practical value of residues 30-44 is still an open question.
- Rodent and dog GH responses do not map one-to-one onto other species, and the GH axis is strongly influenced by age, sex and nutritional state in all of them.
Regulatory status
A tesamorelin drug product was approved by the FDA in 2010 for a specific indication in HIV-associated lipodystrophy. GHRH and its analogs are on the World Anti-Doping Agency’s Prohibited List under S2 (peptide hormones, growth factors, related substances and mimetics). The tesamorelin sold by Rogue Compounds is a research reagent, not that approved drug product, and is not for human use.
Handling and storage in the lab
The lyophilized peptide should be kept sealed and refrigerated at 2–8°C (36–46°F), protected from light.
Sourcing and documentation
Tesamorelin is produced in small batches for Rogue Compounds. Every vial carries a batch number and a QR code that opens the independent U.S. testing lab’s own report for that batch. The same batch COA is posted on the product page and in the COA Library.
View Tesamorelin on Rogue Compounds
References
- Ling N, et al. Isolation, primary structure, and synthesis of human hypothalamic somatocrinin: growth hormone-releasing factor. Proc Natl Acad Sci USA. 1984;81:4302-4306. PMID 6431406
- Mayo KE. Molecular cloning and expression of a pituitary-specific receptor for growth hormone-releasing hormone. Mol Endocrinol. 1992;6(10):1734-1744. PMID 1333056
- Mayo KE, et al. Regulation of the pituitary somatotroph cell by GHRH and its receptor. Recent Prog Horm Res. 2000;55:237-266. PMID 11036940
- Ferdinandi ES, et al. Non-clinical pharmacology and safety evaluation of TH9507, a human growth hormone-releasing factor analogue. Basic Clin Pharmacol Toxicol. 2007;100(1):49-58. PMID 17214611
- Falutz J, 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. J Acquir Immune Defic Syndr. 2010;53(3):311-322. PMID 20101189
- Dhillon S. Tesamorelin: a review of its use in the management of HIV-associated lipodystrophy. Drugs. 2011;71(8):1071-1091. PMID 21668043
Research use only. Rogue Compounds products are sold strictly for laboratory research. They are not for human or veterinary use, and nothing in this article is medical advice. The studies cited here describe published research, not this product or any use of it.