Tesamorelin

Tesamorelin is a synthetic 44-amino-acid analogue of human growth hormone releasing hormone, GHRH(1-44). It differs from the native sequence by a trans-3-hexenoyl group attached at the N-terminus.

That N-terminal modification is the structurally significant feature: native GHRH is rapidly cleaved by dipeptidyl peptidase-4, and the added moiety confers resistance to that cleavage, which is why the analogue is characterised by greater stability than the unmodified peptide in preclinical models.

It is studied as a GHRH receptor agonist, a different receptor family from the growth hormone secretagogue receptor bound by the pentapeptide secretagogues.

Supplied as a lyophilised (freeze-dried) powder in a sealed vial under vacuum. Lyophilisation removes water by sublimation, which is what allows a peptide to remain stable at ambient temperature during transit where a solution would degrade.

Reconstitution in a laboratory setting is typically performed with bacteriostatic water, introduced slowly against the vial wall rather than directly onto the powder cake. Peptide bonds are susceptible to shear, so the vial is swirled to dissolve rather than shaken.

Lyophilised and sealed, the vial is stable at 2 to 8 degrees Celsius and tolerates ambient temperature in transit. For storage beyond several months, minus 20 degrees Celsius is standard.

Once in solution the stability window shortens considerably and refrigeration is required. Repeated freeze-thaw cycles are the most common cause of degradation in a reconstituted peptide, so solutions are generally aliquoted rather than frozen and thawed as a single volume.

Every batch is independently tested through seven rounds of analysis. Identity is confirmed by mass spectrometry and purity quantified by reverse-phase HPLC, with the resulting Certificate of Analysis published against the specific batch rather than the product line.

Testing is performed by third-party laboratories operating to ISO 17025. The COA for the batch currently shipping is linked from this page and archived at /lab-tests.