Tesamorelin Research Peptide

Tesamorelin peptide UK from Crown Peptides is a synthetic analogue of growth-hormone-releasing hormone studied through the GHRH receptor. It carries the full 44-amino-acid sequence of human GHRH, capped at its N-terminus with a trans-3-hexenoyl group, and its research spans GHRH receptor pharmacology, pituitary growth-hormone release, IGF-1-related signalling and metabolic-endocrine models.

It contains a structural modification designed to improve resistance to enzymatic degradation. Native GHRH is quickly cut between its second and third amino acids by dipeptidyl peptidase IV; Tesamorelin’s hexenoyl group sits on that exact end of the molecule and protects it, while the remaining 44 residues match the human hormone.

It promotes growth-hormone signalling through the GHRH receptor, which is mechanistically different from ghrelin-receptor secretagogues such as GHRP peptides [GHRP-6]. For a model that uses both receptor types together, see CJC-1295 + Ipamorelin.

Same peptide, different product. Egrifta is the brand name under which Theratechnologies’ Tesamorelin was approved by the US FDA in 2010 for one specific indication in people living with HIV. Crown Peptides supplies the Tesamorelin peptide itself as a lyophilised research material, with its own batch testing and Certificate of Analysis; it is not the branded medicine.

The two take different design routes. Sermorelin is the shortest fragment of GHRH that keeps full receptor activity, residues 1 to 29. Tesamorelin keeps the whole 44-residue hormone and protects it with an N-terminal cap instead. Researchers comparing the two can therefore ask whether the extra 15 residues change anything in their model. Sermorelin is available separately.

All three point to one peptide. TH9507 was the code Theratechnologies used during development, before the name Tesamorelin was adopted, and “acetate” simply describes the salt form in which the peptide is usually supplied.

They sit at opposite ends of the timing scale. Tesamorelin has a mean elimination half-life of around 11 minutes in human pharmacokinetic studies, so it produces short bursts of GHRH signalling. CJC-1295 with DAC binds albumin in the blood and keeps GH raised for days, which suits studies of sustained exposure instead.

Visceral fat and liver fat tend to travel together, so once the approval trials showed a selective drop in abdominal fat, the liver was a natural next target. In a 12-month randomised trial in people with HIV and fatty liver disease, published in The Lancet HIV, liver fat fell further with Tesamorelin than with placebo, and 35% of the Tesamorelin group ended the year below the 5% liver-fat threshold, against 4% on placebo.

Not in the pooled trial data. The meta-analysis described in the Research section found significant reductions in visceral adipose tissue and trunk fat, but no significant change in subcutaneous fat or BMI. That selectivity for deep abdominal fat is one of the most distinctive features of the Tesamorelin literature.

The FDA approved it in 2010 on the strength of two placebo-controlled trials with CT-measured fat loss. Theratechnologies later withdrew its European application, in June 2012, after the European Medicines Agency’s committee questioned whether the fat reduction gave meaningful health benefit, raised concerns about long-term exposure to higher IGF-1, and noted that trial participants differed from the typical European patient population.

The evidence points that way. In a two-week study of 13 healthy men, overnight sampling showed larger GH peaks and higher basal GH secretion, with IGF-1 rising substantially, while insulin-stimulated glucose uptake did not change significantly. Because somatostatin still controls the timing of each burst, a GHRH analogue amplifies the existing rhythm rather than replacing it.

Results so far are mixed. A University of Washington trial in 137 older adults who completed 20 weeks, some healthy and some with mild cognitive impairment, reported a favourable effect on executive function compared with placebo. A later Phase II trial in ageing HIV-positive adults found no significant between-group difference, so the question remains open.

Only the quantity of material in the vial. Both hold the same synthetic GHRH analogue, tested to the same standard and supplied as lyophilised powder with a batch-specific certificate. The 20 mg vial works out cheaper per milligram and keeps a longer protocol on a single lot number, while the 10 mg vial suits shorter or exploratory work, since reconstituted peptide has a limited working life. Either strength can also be ordered five or ten at a time, all drawn from one batch, so parallel arms start from identical material.

The single S in C221H366N72O67S comes from one methionine at position 27 of the sequence. Methionine is the residue most prone to oxidation, and an oxidised molecule shows up in mass spectrometry as a companion signal 16 Da heavier than the parent. It is one of the clearest reasons to keep the powder cold, dry and away from light, as set out in the storage section.

Being a large molecule, Tesamorelin picks up several charges in electrospray mass spectrometry and appears as a ladder of peaks, which software folds back into one value matching the free-base molecular weight of 5135.86 g/mol. The roughly seven acetate counter-ions per molecule travel with the powder but are not part of that figure.