What tesamorelin is
Tesamorelin is a synthetic analogue of human growth hormone-releasing hormone, built on the full 44-amino-acid sequence rather than the truncated 1-29 fragment that most GHRH analogues use. A trans-3-hexenoyl group is attached at the N-terminus, protecting the molecule from the enzymatic cleavage that clears native GHRH within minutes.
At roughly 5,136 Da it is one of the larger peptides in routine research use, and the size has consequences for both its synthesis and its characterisation.
Molecular profile
| Property | Value |
|---|---|
| Development code | TH9507 |
| CAS number | 218949-48-5 |
| Length | 44 amino acids |
| Molecular weight | ~5,136 Da |
| Modification | trans-3-hexenoyl group at the N-terminus |
| Receptor target | GHRH receptor |
| Appearance | White lyophilised powder |
Full-length versus fragment
The receptor-activating activity of GHRH resides in the first 29 residues, which is why so many analogues stop there — a 29-mer is substantially cheaper and more reliable to synthesise than a 44-mer.
Tesamorelin takes the other route: keep the whole native sequence and solve the stability problem at the N-terminus with an acyl group. The practical consequence is a molecule closer to the endogenous ligand, at the cost of a harder synthesis.
Both strategies converge on the same receptor. The choice between them in a research setting usually comes down to whether the work needs the full sequence or is indifferent to it.
Research context
Tesamorelin is used in growth hormone axis research as a GHRH receptor agonist — receptor binding and functional cAMP work in pituitary cell models, and comparative studies against fragment-based analogues. Clinical literature exists for a specific indication in visceral adipose tissue, and that work informs the research interest without being a claim we make about the material we supply.
Supplied for in-vitro laboratory research only. No therapeutic claim is made and no dosing or administration guidance is provided.
Analytical notes
Forty-four residues is a long solid-phase synthesis, and the analytical consequences follow directly.
Deletion sequences accumulate. Each coupling step is a chance for incomplete reaction, and over 44 steps those chances compound. The impurity profile of a long peptide is therefore richer than a short one's, and the species of interest — a 43-mer missing one residue — sits very close to the main peak on reversed-phase chromatography. This is a compound where the chromatogram is worth considerably more than the number extracted from it.
Mass confirmation resolves truncation. A 43-mer and a 44-mer differ by one residue's mass, which is well within the resolving power of routine MS and well outside what chromatography reliably separates.
Lyophilisation quality matters more at this size. Larger peptides are more sensitive to the state of the freeze-dried cake, and a collapsed or discoloured cake indicates a lyophilisation cycle or a storage excursion that has already compromised the material regardless of what the purity figure says. See water content and lyophilisation quality.
Handling and storage
Store sealed at −20 °C, protected from light and moisture, and bring fully to room temperature before opening — this matters more for a large peptide than a small one, because condensation onto a cold cake introduces water into a formulation that was dried specifically to exclude it. Reconstitute by running diluent down the vial wall and swirling gently; do not shake. Store solution at 2–8 °C, protected from light, and avoid repeated freeze-thaw.
What we supply
Released against a ≥99% purity specification, with HPLC purity and mass spectrometry identity confirmation on every batch and a batch-specific Certificate of Analysis that records cake appearance alongside the analytical results. Select batches additionally receive independent third-party purity verification.