Tesamorelin is a synthetic 44-residue analogue of human growth hormone releasing hormone, GHRH (1-44), carrying a trans-3-hexenoyl group on the N-terminal tyrosine. That single modification is what distinguishes it from the native sequence, and it makes the peptide a stable reference agonist at the GHRH receptor for cell-based signalling work. NuVion supplies Tesamorelin as a laboratory chemical for in vitro research use only.
Key facts
| Type | Synthetic GHRH analogue |
| Amino acid count | 44 |
| Parent sequence | Human GHRH (1-44) amide |
| Modification | Trans-3-hexenoyl group at the N-terminal tyrosine |
| Molecular formula | C221H366N72O67S |
| Molecular weight | 5135.9 g/mol |
| CAS number | 218949-48-5 |
| Supplied form | Lyophilised powder in a sealed vial |
Tesamorelin
$119 AUD
View productResearch use only. Not for human or veterinary use.
Structure and chemistry
Native GHRH (1-44) is the full-length hypothalamic releasing peptide. Its first two residues, tyrosine and alanine, form the recognition site for dipeptidyl peptidase 4, which cleaves the N-terminal dipeptide and destroys receptor activity, since GHRH signalling depends absolutely on an intact N-terminus. Tesamorelin addresses that by attaching a trans-3-hexenoyl group, a six-carbon unsaturated acyl chain, to the alpha-amino group of tyrosine 1. The modification blocks the peptidase from engaging its substrate while leaving the residues that contact the receptor unchanged.
The peptide adopts an amphipathic alpha helix over much of its length in membrane-mimetic conditions, with the helix broken near the middle. The N-terminal region carries the activation determinants and the C-terminal region contributes binding affinity, a division common across the secretin family of peptide hormones. Tesamorelin retains the C-terminal amide of the native (1-44) amide form. At 44 residues and just over 5 kDa it sits between the short synthetic peptides and the glycoprotein hormones in size, and it is long enough that solid phase synthesis quality shows clearly in the HPLC trace as deletion and truncation sequences.
Practical stability follows the usual pattern for a long peptide with several labile residues. There is a methionine that can oxidise and asparagine and glutamine residues that can deamidate over time in solution, both of which appear as closely eluting peaks on RP-HPLC and as characteristic mass shifts of plus 16 and plus 1 respectively. The hexenoyl group itself is an alkene and is best kept away from strong oxidants. Purity is determined by RP-HPLC and identity confirmed by mass spectrometry.
Mechanism of action
The GHRH receptor is a class B G protein-coupled receptor expressed on pituitary somatotrophs. Binding follows the two-domain model typical of the class: the C-terminal portion of the peptide docks into the large extracellular domain, which positions the N-terminal region to insert into the transmembrane core and trigger the conformational change that activates the receptor. This is why N-terminal integrity is decisive and why dipeptidyl peptidase 4 cleavage abolishes activity, and it is the structural logic behind the hexenoyl modification.
Activation couples principally to Gs. Adenylyl cyclase raises cyclic AMP, protein kinase A is activated, and phosphorylated CREB drives transcription of the growth hormone gene and of Pit-1, the pituitary-specific transcription factor. Protein kinase A also phosphorylates voltage-gated calcium channels, so calcium influx rises and supports secretory vesicle release, which is measurable as growth hormone in conditioned medium by immunoassay. A secondary coupling to Gq and phospholipase C has been described at higher receptor occupancy. In cell-based pharmacology the compound is used as the reference full agonist against which analogues and secretagogues acting through the separate ghrelin receptor are compared, and the two receptor systems are often run side by side to show that they are independent.
Research applications
- Cyclic AMP accumulation assays in GHRH receptor expressing cell lines by HTRF, AlphaScreen or reporter, using Tesamorelin as reference full agonist.
- Growth hormone secretion assays in pituitary somatotroph culture, quantifying conditioned medium by ELISA.
- Competition binding at the GHRH receptor to determine affinity for analogues under test.
- CREB phosphorylation and Pit-1 expression measurement by Western blot and qPCR.
- Side-by-side comparison with ghrelin receptor secretagogues to demonstrate independent receptor pathways.
- Dipeptidyl peptidase 4 stability assays comparing the hexenoyl-modified analogue with unmodified GHRH (1-44).
Tesamorelin sits in NuVion’s Metabolism category alongside the other compounds used in somatotropic axis research.
Handling in the laboratory
Tesamorelin is supplied lyophilised and is reconstituted with bacteriostatic water added slowly down the wall of the vial, then swirled gently until dissolved. It is not shaken, since a peptide of this length with an amphipathic helix will foam and aggregate at an air-liquid interface. The reconstitution calculator converts vial content and diluent volume into a stock concentration. Working dilutions for receptor assays are commonly prepared in buffer containing a carrier protein, since a 5 kDa amphipathic peptide adsorbs to plate and tube surfaces at low concentration.
Unopened vials are kept sealed, dry and refrigerated as stated on the product documentation. Reconstituted solution is refrigerated and used within the period given there, or aliquoted into single-use volumes and frozen to avoid repeated freeze-thaw cycles. Oxidation of the methionine is the slow chemical change to watch over extended storage in solution, and it is detected as an additional early-eluting peak on RP-HPLC with a mass shift of plus 16. Where full agonist behaviour matters, a concentration-response curve on a receptor-expressing line is the functional check.
Testing and supply from NuVion
NuVion’s Tesamorelin is manufactured at a GMP-audited facility and independently tested by Janoshik Analytical, with purity determined by RP-HPLC and identity confirmed by mass spectrometry. The Certificate of Analysis for a tested batch is published on the product page and in the COA library. The peptide is supplied lyophilised in sealed vials and dispatched from within Australia.
Related compounds
Other compounds acting on the somatotropic axis include Sermorelin, the GHRH (1-29) fragment, CJC-1295 No DAC, a tetra-substituted GHRH analogue, and Ipamorelin, which acts at the separate ghrelin receptor.
Frequently asked questions
What is Tesamorelin used for in research?
It is used as the reference full agonist at the GHRH receptor in cyclic AMP accumulation assays, in competition binding to determine affinity for analogues, in growth hormone secretion assays on pituitary cell culture, and in stability comparisons against unmodified GHRH.
What does the hexenoyl group do?
It caps the alpha-amino group of the N-terminal tyrosine, which is the residue dipeptidyl peptidase 4 recognises. Blocking that cleavage preserves the N-terminal region that inserts into the receptor core, so the analogue retains activity far longer in enzyme-containing medium than the native sequence.
Is Tesamorelin a therapeutic good in Australia?
No. NuVion’s Tesamorelin is a laboratory chemical for in vitro research. It is not included in the Australian Register of Therapeutic Goods, has not been assessed by the Therapeutic Goods Administration, and is not for human or veterinary use.
How should Tesamorelin be stored?
Lyophilised vials are kept sealed, dry and refrigerated per the product documentation. Reconstituted solution is refrigerated and used within the stated period, or aliquoted into single-use volumes and frozen. Solutions are swirled and never shaken, since the amphipathic helix aggregates at an air-liquid interface.
Research use only. This product is a laboratory chemical supplied for in vitro research. It is not included in the Australian Register of Therapeutic Goods and has not been assessed by the Therapeutic Goods Administration for quality, safety or efficacy. It is not for human or veterinary use, and nothing on this page is a representation about therapeutic use.
