What it is
Tesamorelin is a synthetic analogue of growth-hormone-releasing hormone, reproducing the full 44-residue sequence of that molecule with one deliberate addition: a trans-3-hexenoyl group attached at the N-terminus. Where CJC-1295 truncates the parent hormone to its first 29 residues and substitutes within them, this compound keeps the whole chain and modifies the end.
| Property | Value | Where it is confirmed |
|---|---|---|
| Residue count | 44 | Synthesis record |
| N-terminal modification | trans-3-hexenoyl group | Synthesis record; identity result |
| Approximate mass | near 5,136 g/mol | Certificate of analysis |
| Parent molecule | Growth-hormone-releasing hormone, full sequence | Published literature |
| Physical form supplied | Lyophilized solid | Label and batch record |
Why length is the dominant fact
Forty-four residues is a long solid-phase synthesis. Each coupling step is another opportunity for a chain to fail to extend, and the probability of at least one failure across a chain compounds with every position added. The practical consequences for a report are direct:
- Deletion sequences are the expected impurity class, not oxidation products or rearrangements. A 44-residue chain missing one residue is chemically very similar to the complete chain, so those species elute close to the main peak.
- The impurity envelope is wider than on a short peptide. Purity figures for long chains are typically lower than for a five- or seven-residue compound, and that is a property of the class rather than a defect.
- The chromatogram matters more than the number. With many closely eluting related species, how well the method resolved them determines what the percentage even means. See how to read an HPLC chromatogram.
What identity has to confirm
The hexenoyl group adds roughly 96 mass units to the unmodified chain. That is comfortably beyond any method's tolerance, so a mass-based identity result distinguishes the modified compound from its unmodified parent directly — and material that never received the acyl group is exactly the impurity most worth ruling out, because it is a legitimate peptide that simply is not this product.
This is the same structural situation as the DAC linker on CJC-1295: a compound defined by an addition, where the failure mode is the addition being absent. Where identity is reported as HPLC-RTM, the report should name the reference standard the retention time was matched against.
Storage of the lyophilized solid
Supplied as a freeze-dried solid and governed by temperature and moisture. Long chains carry more internal structure than short ones and are correspondingly less tolerant of repeated temperature cycling; cold, sealed storage with minimal handling is the stable state.
Stability is a documented property rather than an assumed one: a laboratory establishes it by holding material under defined conditions and re-analysing at intervals. Where a retest date is stated, the question worth asking is what data supports it. See storing lyophilized research materials.
What the published literature covers
The research record is preclinical and clinical in parts, with published work on growth-hormone-releasing hormone analogues covering receptor pharmacology, animal models, and metabolic endpoints. A substantial share concerns the native hormone rather than this analogue, and the N-terminal modification exists precisely because it changes how the molecule resists enzymatic breakdown relative to the native form.
The compound has not completed the regulatory process that would establish safety or efficacy for any medical indication, and findings in animal models and cell culture do not transfer automatically to other species. Arctic Lab Supply does not publish research conclusions, recommend applications, or provide guidance on experimental design.