Tesamorelin: Research Reference

Tesamorelin is a synthetic analogue of human growth hormone releasing hormone (GHRH): the complete 44-residue GHRH(1-44) amide sequence with a trans-3-hexenoyl group attached to the first tyrosine. That single addition protects the front of the chain from the enzyme dipeptidyl peptidase 4, which is why tesamorelin persists long enough to study when the native hormone is cleared within minutes.

This reference collects what is known about the molecule itself: how it is built, what the research literature has found, and how its sequence shapes the way it behaves in a vial. Each section below has its own page, written for laboratory handling of the lyophilised material.

Molecular reference

Name	Tesamorelin
Also known as	TH9507; trans-3-hexenoyl-hGRF(1-44)-NH2
Sequence	(E)-hex-3-enoyl-Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-Gln-Gln-Gly-Glu-Ser-Asn-Gln-Glu-Arg-Gly-Ala-Arg-Ala-Arg-Leu-NH2
Residues	44
Molecular formula	C221H366N72O67S
Molecular weight	5136 g/mol
CAS number	218949-48-5
Class	Peptide analogue of GHRH (growth hormone releasing factor)

A few features of that sequence matter for everything that follows. There is one methionine (position 27), two asparagines (8 and 35) and two aspartates (3 and 25). There is no cysteine, tryptophan or histidine. Eight residues carry a positive charge at neutral pH (six arginines and two lysines) against four acidic residues, and the N-terminus is capped by the hexenoyl group, so the molecule is strongly cationic. The C-terminus is an amide, as in the natural hormone.

What it is studied for

Tesamorelin’s best documented effect is on visceral fat. In a 26-week randomised trial of 412 adults with HIV and abdominal fat accumulation, visceral adipose tissue fell by 15.2% with tesamorelin while it rose by 5.0% with placebo, triglycerides fell, and IGF-1 rose by 81% (Falutz, New England Journal of Medicine, 2007). A pooled analysis of two phase 3 trials confirmed the visceral fat reduction (Falutz, Journal of Clinical Endocrinology and Metabolism, 2010). The trial record is summarised in tesamorelin and visceral fat.

Liver fat is the second major line of work. In a 12-month randomised, double-blind trial in people with HIV and fatty liver disease, tesamorelin reduced hepatic fat fraction by an absolute 4.1% more than placebo, a 37% relative reduction, and 35% of the tesamorelin group fell below the 5% threshold compared with 4% on placebo (Stanley, Lancet HIV, 2019). More detail is in tesamorelin and liver fat.

Cognition is a newer interest. A 20-week controlled trial in healthy older adults and adults with mild cognitive impairment found a favourable effect on executive function, with IGF-1 rising within the physiological range (Baker, Archives of Neurology, 2012). The preclinical basis for all of this work, including resistance to dipeptidyl peptidase 4 in plasma, was set out in the original pharmacology package (Ferdinandi, Basic and Clinical Pharmacology and Toxicology, 2007). Why one small chemical change made the difference is explained in tesamorelin: one small change to a natural hormone.

The sections of this reference

Stability

Tesamorelin degrades in water at three known sites: deamidation at asparagine 8, isomerisation and cleavage at aspartate 3, and oxidation of methionine 27. The stability page explains each route, why the mixed window is short, and what pH, light and temperature do.

Solubility

The strong positive charge makes tesamorelin readily water soluble, but its long amphipathic helix can self-associate at high concentration. The solubility page covers bacteriostatic water, saline, concentration ranges and why haze or gel forms.

Handling

Bench practice for a 44-residue peptide that is sensitive to agitation and oxidation, from warming the vial before opening to labelling it. See the handling page, including a list of common mistakes.

On arrival

What the lyophilised cake should look like, why it travels without an ice pack, and where it goes first. See tesamorelin on arrival.

FAQ

Short answers to the questions researchers ask most about storing, mixing and keeping tesamorelin are on the tesamorelin FAQ.

Storage and reconstitution

Storage windows before and after mixing, including the 7-day limit for a mixed vial, are on how long does tesamorelin last. Water volumes and the resulting concentrations for a 10 mg vial are on tesamorelin reconstitution with bacteriostatic water.

Vistara Labs supplies tesamorelin 10 mg as a lyophilised vial for laboratory research. For sourcing questions, see tesamorelin in Canada: a researcher’s buying guide.

Sources: Falutz J et al., N Engl J Med 2007 (PMID 18057338); Falutz J et al., J Clin Endocrinol Metab 2010 (PMID 20554713); Stanley TL et al., Lancet HIV 2019 (PMID 31611038); Baker LD et al., Arch Neurol 2012 (PMID 22869065); Ferdinandi ES et al., Basic Clin Pharmacol Toxicol 2007 (PMID 17214611).