Tesamorelin Pen
10 mg of trans-3-hexenoyl GHRH(1-44) amide in solution in a 3 mL autoinjector, about 3.3 mg/mL. Filled from peptide tested in the manufacturer’s own laboratory.
| Compound | Tesamorelin (trans-3-hexenoyl-GHRH(1-44)-NH2) |
|---|---|
| CAS number | 218949-48-5 |
| Molecular formula | C221H366N72O67S |
| Contents | Tesamorelin: 10 mg per 3 mL pen (0.33% w/v) |
| Form | Sterile aqueous solution in bacteriostatic water (0.9% benzyl alcohol), supplied in a 3 mL glass cartridge inside a preloaded autoinjector pen fitted with a needle |
| Storage, sealed | Store at 2–8 °C in the original carton, protected from light |
| Format | Solution in a 3 mL pre-filled pen |
Sizes and lots
- 10 mg · 1 pen — $98.99
- 10 mg · Kit of 10 — $880.02
Tesamorelin is human growth hormone-releasing hormone in full, all 44 residues with a C-terminal amide, carrying a trans-3-hexenoyl group on the N-terminus. This listing is a preloaded autoinjector pen with 10 mg of the peptide already dissolved in a 3 mL cartridge, so there is no powder to reconstitute. The published research is mostly randomised trials in adults with HIV, which measured abdominal and liver fat and metabolic markers, plus a trial of cognition in older adults.
What is in the pen
The pen holds 10 mg of tesamorelin in a 3 mL cartridge, about 3.3 mg/mL. It is the same trans-3-hexenoyl GHRH(1-44) amide sold freeze-dried in the Tesamorelin 10 mg vial. The vial's safety data sheet classifies tesamorelin itself as a category 2 reproductive toxicant (H361, suspected of damaging fertility or the unborn child), a hazard of the peptide whatever its form. Storage conditions are printed on the pen label. The concentration is fixed at filling, whereas a vial lets the laboratory choose its own volume; the general trade-offs are set out in peptide pen vs vial.
GHRH in solution
Tesamorelin's chain is the native 44-residue sequence, so it keeps the two sites where GHRH is known to degrade in water. Bongers and colleagues studied GRF(1-44)-NH₂ itself and found cleavage after Asp3 in acid, isomerisation of Asp3 above pH 4 and deamidation of Asn8 at pH 8; every product had much lower in vitro potency, and the peptide was most stable at pH 4 to 51. In a related GRF analogue kept at pH 7.4 and 37 °C, the Asn8-deamidated form was 400 to 500 times less potent than the parent2. Both studies used GRF without the hexenoyl group, which sits on the N-terminus two residues from Asp3, and neither tested this pen's solution, so they describe the chemistry rather than set a shelf life.
What the research covers
Tesamorelin keeps the full 44-residue sequence of the GHRH that Guillemin's group isolated in 1982, a peptide whose synthetic copy stimulated growth hormone secretion with full activity in vitro and in vivo3. Its clinical record centres on people with HIV who had built up abdominal fat on antiretroviral therapy. In a 26-week randomised trial of 412 such patients, CT-measured visceral adipose tissue fell 15.2% on tesamorelin against a 5.0% rise on placebo, with IGF-I up 81% and no significant difference in glycaemic measures4. Triglycerides and the ratio of total to HDL cholesterol also moved in the tesamorelin group's favour, adverse events were similar in both arms, and more patients on tesamorelin withdrew because of one4. A 12-month trial in 61 people with HIV and non-alcoholic fatty liver disease later found a larger fall in hepatic fat fraction than with placebo, without differences in glucose or glycated haemoglobin; 35% of the tesamorelin group and 4% of the placebo group finished below the 5% fat-fraction threshold5.
The trial in older adults, the withdrawal data and what remains unsettled are summarised on the Tesamorelin 10 mg page and in sermorelin vs ipamorelin vs tesamorelin.
Frequently asked questions
How does the pen differ from the tesamorelin vial?
The vial holds dry peptide kept cold and dissolved in the lab when needed, at whatever concentration the work calls for. The pen holds the same peptide already in solution, 10 mg in 3 mL, so the concentration is fixed and the solution chemistry starts at filling.
Do the clinical trials apply to this pen?
Only as background on the molecule. The trials tested tesamorelin in defined patient groups and did not use research material or a preloaded solution, and none of the cited abstracts addresses how long tesamorelin stays stable in solution.
What does the testing cover for the pen?
Testing applies to the peptide lot used to fill the pen, not to the finished solution in the cartridge. The testing section on this page explains where published certificates are listed and how to check one by number and key.
References
- Bongers J, Heimer EP, Lambros T, et al. Degradation of aspartic acid and asparagine residues in human growth hormone-releasing factor. Int J Pept Protein Res. 1992;39(4):364-74. DOI · PubMed
- Friedman AR, Ichhpurani AK, Brown DM, et al. Degradation of growth hormone releasing factor analogs in neutral aqueous solution is related to deamidation of asparagine residues. Replacement of asparagine residues by serine stabilizes. Int J Pept Protein Res. 1991;37(1):14-20. DOI · PubMed
- Guillemin R, Brazeau P, Böhlen P, et al. Growth hormone-releasing factor from a human pancreatic tumor that caused acromegaly. Science. 1982;218(4572):585-7. DOI · PubMed
- Falutz J, Allas S, Blot K, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med. 2007;357(23):2359-70. DOI · PubMed
- Stanley TL, Fourman LT, Feldpausch MN, et al. Effects of tesamorelin on non-alcoholic fatty liver disease in HIV: a randomised, double-blind, multicentre trial. Lancet HIV. 2019;6(12):e821-e830. DOI · PubMed
For laboratory research use only. Not for human or veterinary consumption. Products have not been evaluated by the U.S. Food and Drug Administration and are not intended to diagnose, treat, cure or prevent any disease.