Tesamorelin 10mg

What is Tesamorelin ?

Peptaro supplies tesamorelin peptide, developed under the code TH9507, as a lyophilised powder in 5mg and 10mg vials. Each batch has its own third-party certificate.

Tesamorelin is an agonist at the GHRH receptor on anterior pituitary somatotrophs. Native GHRH is cleaved between Tyr1 and Ala2 by dipeptidyl peptidase-4 and inactivated within minutes. The hexenoyl cap on Tyr1 blocks that cleavage. Ferdinandi et al. (Basic Clin Pharmacol Toxicol, 2007) reported resistance to DPP-IV, slower degradation in rat, dog and human plasma, and enhanced potency and duration of action.

Tesamorelin is a 44 residue synthetic analogue of human growth hormone releasing hormone, hGRF(1-44)NH₂, developed under the code TH9507 and acting as an agonist at the GHRH receptor on anterior pituitary somatotrophs. Its single structural modification is a trans-3-hexenoyl group on Tyr1, which blocks the dipeptidyl peptidase-4 cleavage site between Tyr1 and Ala2 that inactivates native GHRH within minutes. The non-clinical evaluation of TH9507 published in Basic and Clinical Pharmacology and Toxicology in 2007 reported resistance to dipeptidyl aminopeptidase-IV alongside enhanced potency and duration of action.

Tesamorelin Research Applications

Tesamorelin is used in endocrine research on GHRH receptor pharmacology, somatotroph biology and DPP-4 resistance as a peptide stabilisation strategy. Because it acts upstream of the pituitary, endogenous GH secretion and feedback stay in the loop. In a 2 week study of 13 healthy men, Stanley et al. (J Clin Endocrinol Metab, 2011) reported higher mean overnight GH, GH peak area and basal GH secretion. Insulin-stimulated glucose uptake did not change significantly. Clinical trials ran mainly in HIV-associated abdominal fat accumulation, in supervised patient populations.

Tesamorelin is used in endocrine research examining GHRH receptor pharmacology, dipeptidyl peptidase-4 resistance as a peptide stabilisation strategy, somatotroph biology, and the kinetics of endogenous growth hormone secretion when driven from upstream of the pituitary rather than replaced directly. Stanley and colleagues (Journal of Clinical Endocrinology and Metabolism, 2011) reported increased basal and pulsatile GH secretion in healthy men with no change in pulse frequency, which is the endpoint distinguishing a GHRH analogue from recombinant growth hormone. The clinical literature ran principally in HIV associated lipodystrophy, with a later randomised trial extending to non-HIV subjects with reduced GH secretion. Those findings belong to defined patient populations studied under medical supervision and are reported here as literature background only.

Tesamorelin vs CJC-1295 vs Sermorelin

All three act at the GHRH receptor. They differ in sequence length and in how they resist enzymatic breakdown. Sermorelin is the truncated GHRH(1-29) fragment with no stabilising modification, so it is the shortest-acting of the three. CJC-1295 is a modified GRF(1-29) analogue, sold with or without the DAC linker that extends its duration. Tesamorelin keeps the full 44 residue GHRH sequence and gets its stability from one hexenoyl group on Tyr1. Choose tesamorelin when a design calls for full-length GHRH with DPP-4 resistance.

All three act at the same receptor, and the differences are sequence length and the mechanism of enzymatic stabilisation. Sermorelin is the truncated GHRH(1-29) fragment with no stabilising modification, so it is the shortest-acting of the three. CJC-1295 is a modified GRF(1-29) analogue, supplied with or without the DAC linker, where the linker is what extends duration substantially. Tesamorelin is the outlier in retaining the complete 44 residue GHRH sequence, with stability coming from one trans-3-hexenoyl group on Tyr1 rather than from truncation or a conjugated linker. Researchers choose tesamorelin when a full-length GHRH sequence with DPP-4 resistance is what the design calls for, and it is the only GHRH analogue of the three to have completed phase 3 clinical trials, which means its human pharmacology is documented in far more detail than that of the GRF(1-29) analogues.

Storage and Reconstitution

When storing tesamorelin powder, keep the sealed vial at -20°C, dry and dark. Heat, light and moisture shorten its shelf life. Once mixed, keep the solution refrigerated at 2-8°C and freeze single-use aliquots for longer holding. Methionine 27 and the two tyrosines are the oxidation-sensitive positions, so minimise headspace air. Avoid strongly alkaline buffers and heat, which could hydrolyse the hexenoyl group that gives DPP-4 resistance.

Protect from light throughout, since the methionine at position 27 and the two tyrosine residues are the oxidation-sensitive positions in the sequence. There are no cysteines and therefore no disulfide network to scramble, but avoid conditions that could hydrolyse the N-terminal hexenoyl group, which is the feature giving the molecule its dipeptidyl peptidase-4 resistance.

Vials are sold on their own, without bacteriostatic water for mixing or other supplies.

How to reconstitute and handle

Let the vial reach room temperature so condensation does not settle on the cake. Run bacteriostatic water slowly down the inside wall of the vial and swirl gently until the solution is clear and colourless. Do not shake or vortex, because the long chain and the hydrophobic hexenoyl cap raise aggregation risk. Label the vial with the reconstitution date.

• Allow the vial to reach room temperature before opening so condensation does not settle on the cake.
• The single methionine at position 27 and the two tyrosine residues are the oxidation-sensitive positions in the sequence. Minimise headspace air exposure, protect from light, and do not leave dilute solutions standing at room temperature.
• There are no cysteines in tesamorelin, so there is no disulfide network to scramble. Aggregation risk sits instead with the hydrophobic hexenoyl cap and the length of the chain, which is another reason to avoid agitation and repeated warming.
• Note that the N-terminal acyl group is what confers dipeptidyl peptidase-4 resistance. Any handling that could hydrolyse it, such as strongly alkaline buffers or extended exposure to high temperature, changes the molecule you are actually studying.
• Store the reconstituted solution at 2-8°C and prepare single-use aliquots at -20°C for longer holding. Avoid repeated freeze-thaw cycles.
• Handle under aseptic conditions, swabbing the stopper of both vials with alcohol before each needle entry. The site reconstitution guide and reconstitution calculator cover the full aseptic workflow and dilution arithmetic.

For the full method, see the peptide reconstitution guide and the reconstitution calculator.

Research References

• Non-clinical pharmacology and safety evaluation of TH9507, a human growth hormone-releasing factor analogue (Basic Clin Pharmacol Toxicol, 2007)
• Effects of a growth hormone-releasing hormone analog on endogenous GH pulsatility and insulin sensitivity in healthy men (J Clin Endocrinol Metab, 2011)
• Metabolic effects of a growth hormone-releasing factor in patients with HIV (N Engl J Med, 2007)

Published research on Tesamorelin is indexed on PubMed. See our full UK buyer's guide for Tesamorelin 10mg.