For laboratory and research use only. Not for human consumption.
Native growth hormone-releasing hormone (GHRH) is susceptible to rapid enzymatic degradation. Theratechnologies developed tesamorelin, a 44-amino acid GHRH analogue with a modification at its N-terminus.
The modification is a trans-3-hexenoic acid group attached to the N-terminal tyrosine. It changes the peptide’s susceptibility to enzymatic cleavage. Stability and receptor binding are separate properties and need separate measurements.
What Is Tesamorelin? Chemical Identity & Structure
It carries the full 44-amino acid sequence of human GHRH (1-44). Same building blocks. One critical addition at the front end.
| Property | Value |
|---|---|
| Compound Name | Tesamorelin (TH9507) |
| Parent Sequence | Human GHRH(1-44) |
| CAS Number | 218949-48-5 |
| Molecular Formula | C221H366N72O67S |
| Molecular Weight | 5,135.86 Da |
| Amino Acid Length | 44 residues |
| Classification | GHRH receptor agonist |
| N-Terminal Modification | trans-3-Hexenoic acid |
| PubChem CID | 146681838 |
| Storage | 2 to 8°C (lyophilized powder) |
The N-terminal modification changes how the peptide interacts with proteolytic enzymes. Native GHRH(1-44) has a reported circulating half-life of about 5 to 7 minutes (PMID: 16052083).
Development History
Tesamorelin was developed by Theratechnologies under the laboratory code TH9507. Its design retained the 44-residue GHRH sequence and added an N-terminal modification to alter enzymatic stability.
GHRH Receptor Pharmacology
Tesamorelin is an agonist of the GHRH receptor, a G protein-coupled receptor.
Pituitary GHRH Receptor Binding
GHRH receptors are expressed on somatotroph cells in the anterior pituitary. Tesamorelin binds this receptor. Binding affinity and functional activation are distinct properties and require different assays.
The Signaling Chain
GHRH receptor signaling involves the following cellular steps:
- Gαs activation stimulates adenylyl cyclase.
- cAMP formation occurs when adenylyl cyclase converts ATP to cyclic AMP.
- PKA activation occurs when cAMP activates protein kinase A.
- CREB phosphorylation can occur through PKA signaling. CREB is a transcription factor.
- Secretory signaling involves calcium-dependent exocytosis of GH-containing granules in somatotroph cells.
Cellular signaling measurements and whole-organism hormone patterns are not interchangeable. Assay descriptions should identify the experimental system and the specific readout.
GH and IGF-1
GH and IGF-1 are distinct signaling molecules. IGF-1 concentration is a downstream measurement, not a direct measure of GHRH receptor binding.
Published Research Findings
Research measurements answer different questions. Receptor assays describe binding or signaling, while stability assays track the peptide and its breakdown products.
Receptor and Signaling Measurements
Receptor binding and receptor activation are different endpoints. Binding assays measure interaction with the receptor, while functional assays measure a downstream signal such as cAMP.
Peptide Stability Measurements
Stability measurements track intact peptide and cleavage products over time. Interpreting those measurements requires the experimental conditions, including temperature, pH, and the enzymes present.
Pharmacokinetics: What Researchers Need to Know
Numbers first:
| Parameter | Value |
|---|---|
| Tmax | ~0.15 hours (~9 minutes) |
| Half-life | 26 min (tesamorelin); 38 min (GHRH 1-44 fragment) |
| Metabolism | Proteolytic cleavage to GHRH(1-44) and smaller fragments |
| Protein Binding |
The reported tesamorelin plasma half-life is about 26 minutes. Plasma concentration and downstream signaling are different measurements, so they should not be treated as interchangeable (PMID: 36356032).
Tesamorelin vs. Other GHRH Analogues
Sermorelin, CJC-1295, and tesamorelin differ in sequence length and chemical modifications. The table compares molecular features and reported half-lives.
| Property | Tesamorelin | Sermorelin | CJC-1295 (no DAC) | CJC-1295 (with DAC) |
|---|---|---|---|---|
| Amino Acids | 44 | 29 | 29 (modified) | 29 (modified) |
| GHRH Sequence | Full GHRH(1-44) | GHRH(1-29) | Modified GHRH(1-29) | Modified GHRH(1-29) |
| Key Modification | trans-3-hexenoic acid (N-term) | None (truncated native) | 4 amino acid substitutions | 4 substitutions + DAC |
| Half-life | ~26 min | ~10 to 20 min | ~30 min | ~8 days |
| DPP-IV Resistance | Minimal | High (amino acid subs) | High | |
Against Sermorelin
Sermorelin corresponds to the first 29 amino acids of GHRH and retains GHRH receptor agonist activity. It lacks tesamorelin’s N-terminal trans-3-hexenoic acid group and is susceptible to enzymatic cleavage.
Against CJC-1295
CJC-1295 without DAC, also called Mod GRF 1-29, has substitutions at amino acid positions 2, 8, 15, and 27. These modifications change its susceptibility to enzymatic cleavage. Its reported half-life is about 30 minutes.
The DAC modification allows CJC-1295 with DAC to associate with serum albumin. Its reported half-life is about 8 days. Albumin association distinguishes it chemically from analogues without DAC.
Distinct Receptor Targets
GHRH receptors and ghrelin receptors are different targets. The label CJC-1295/Ipamorelin blend describes a mixture of compounds associated with those two receptor families, not a single peptide sequence.
Analytical Considerations
For peptide experiments, separate material characterization from assay response. Identity, purity, and stability describe the sample, while receptor readouts describe the experimental system.
Laboratory Scope
This article focuses on molecular properties and laboratory measurements. Chemical identity, chromatographic purity, and receptor activity are distinct characteristics.
For tesamorelin, HPLC can characterize chromatographic purity, while mass spectrometry can assess molecular identity. These methods measure different properties.
Product Specifications
| Specification | Details |
|---|---|
| Product | Tesamorelin 10mg |
| Form | Lyophilized powder |
| Purity | ≥98% (HPLC verified) |
| Third-Party Testing | Mass spectrometry + HPLC |
| Storage | 2 to 8°C, protect from light |
| CAS Number | 218949-48-5 |
Related compounds for GH axis research: Sermorelin 2mg, CJC-1295 (Mod GRF 1-29) 2mg, CJC-1295 with DAC 2mg, CJC-1295/Ipamorelin Blend, and Ipamorelin 2mg.
Where Tesamorelin Research Is Heading
Several molecular questions follow from these properties:
Enzymatic stability: Which cleavage products form under defined laboratory conditions, and how quickly does the intact peptide disappear?
Receptor signaling: How do receptor expression and assay conditions affect the measured response?
Structure and activity: How does the N-terminal modification affect binding and susceptibility to proteolysis?
Conclusion
Tesamorelin is a 44-amino acid GHRH analogue with an N-terminal trans-3-hexenoic acid group. Its molecular structure, receptor pharmacology, and enzymatic stability are separate subjects for laboratory measurement.
For tesamorelin, chemical characterization and receptor assays answer different questions. A purity measurement alone does not establish receptor activity.
References
- Falutz J, et al. J Clin Endocrinol Metab. 2007. PMID: 16052083
- Falutz J, et al. Multicenter study of tesamorelin for visceral adiposity. J Acquir Immune Defic Syndr. 2008. PMID: 18057338
- Falutz J, Mamputu JC, Potvin D, et al. Pooled analysis of two Phase 3 trials with safety extension data. Clin Infect Dis. 2012;54:1642-51. PMID: 23015655
- Stanley TL, et al. J Clin Endocrinol Metab. 2014. PMID: 24823457
- Adrian S, et al. Clin Infect Dis. 2019. PMC6766405
- NCT02572323. Phase II Trial of Tesamorelin for Cognition. ClinicalTrials.gov.
For laboratory and research use only. Not for human consumption. This article is intended for educational and informational purposes for qualified researchers.
This educational material discusses laboratory research concepts only. Loti Labs products are intended strictly for research and development use and are not for human consumption.
