Quick answer: "Tesa" is shorthand for tesamorelin, a synthetic 44-amino-acid analog of growth hormone-releasing hormone (GHRH) with an N-terminal trans-3-hexenoyl group that protects it from enzymatic breakdown. It acts on the GHRH receptor on pituitary cells. An approved medicine containing it exists, made by its originator; this guide is about the research compound sold for laboratory work and makes no claims about use in people.
What tesamorelin is
Tesamorelin is a peptide analog of human growth hormone-releasing hormone, the 44-residue hypothalamic hormone that tells the pituitary to release growth hormone. Unmodified GHRH is cleaved within minutes by an enzyme called DPP-4, which removes its first two amino acids and inactivates it. Tesamorelin keeps the full 44-residue sequence and adds a trans-3-hexenoyl group at the N-terminus, which shields the peptide from that cleavage and gives it a longer duration of activity in published pharmacology.
Note the contrast with the shorter analogs. CJC-1295 without DAC is a 29-residue fragment with four substitutions, while tesamorelin is the full-length hormone with one terminal modification. Our tesamorelin research overview and structure and synthesis article give the sequence detail.
What "tesa" means
"Tesa" is community shorthand for tesamorelin, and you will also see "tesa peptide". Because tesamorelin is sometimes confused with the shorter GHRH analogs, match any listing to the compound name and the declared vial size. We supply tesamorelin as a 10 mg research vial.
How it fits among growth hormone-axis peptides
Researchers working on the growth hormone axis use two main families of peptide. GHRH analogs, such as tesamorelin, sermorelin and CJC-1295, act on the GHRH receptor. Secretagogues, such as ipamorelin and hexarelin, act on the ghrelin receptor. The two receptors sit on the same pituitary cell and signal through different routes, which is why the pairs are often studied together. Tesamorelin and sermorelin differ in length and stability: sermorelin is the 29-residue active fragment and is cleared quickly, whereas tesamorelin is the full-length sequence with a protective terminal group.
Our sermorelin vs ipamorelin comparison and the CJC-1295 and ipamorelin guide cover the neighbouring compounds, and the tesamorelin mechanism article goes through the receptor signalling.
Research compound versus approved medicine
Tesamorelin is the active ingredient in a medicine approved for a specific clinical use, made by its originator under pharmaceutical controls. That product is outside the scope of this site. The tesamorelin supplied by V8 Peptides is sold only for laboratory research, such as in vitro assays and preclinical models. It is not the approved product, it is not a substitute for it, and nothing here is guidance for use in people or animals.
Because research material has no regulatory release testing behind it, the buyer relies on the supplier's certificate to know what is in the vial.
Why a 44-residue peptide needs careful testing
A peptide of this length is demanding to synthesize. Many coupling steps mean many chances for deletion and truncation products, and the terminal hexenoyl group is a further chemical step that must go to completion. A sample that lacks the hexenoyl group is a different, less stable molecule, and a chromatogram with a cluster of small peaks beside the main one suggests incomplete purification.
A good certificate therefore reports measured purity with the chromatogram, confirms identity, and gives a measured content. Our tesamorelin purity testing article explains the likely impurities, and understanding HPLC purity explains the trace in general terms.
What to check on a tesamorelin listing
- A certificate for the lot, with lot code, test date and laboratory name.
- Measured HPLC purity and the chromatogram, not only a specification limit.
- Identity confirmed, with the compound named on the report.
- Measured content, compared with the 10 mg label.
- Endotoxin and sterility, which matter for cell-based work.
- Verifiability with the issuing laboratory.
If the format is new to you, how to read a COA walks through a certificate line by line, and our supplier checklist is in how to choose a research peptide supplier.
Common points of confusion
Three confusions come up often. First, tesamorelin is not the same as the shorter GHRH analogs. Sermorelin is the 29-residue fragment, CJC-1295 without DAC is a modified 29-residue analog, and tesamorelin is the full 44-residue sequence with a protective terminal group, so results from one do not transfer to another. Second, GHRH analogs are not secretagogues. They act on the GHRH receptor, while peptides such as ipamorelin and hexarelin act on the ghrelin receptor. Third, a purity figure does not confirm the terminal group. Identity testing should show that the hexenoyl modification is present, because a sample without it is a different molecule.
Experimental design notes
Because GHRH-family peptides are cleared quickly in animal work, the timing of measurement is part of the result. A study that reports a single time point leaves out most of the picture, so look for several sampling times, a baseline taken beforehand and a vehicle control handled identically. Receptor desensitization is also a feature of this system, which means a design that repeats exposure has to account for it. None of this is guidance for use in people or animals; it is the kind of design thinking a controlled study expects.
Where it came from
Tesamorelin was developed from the native GHRH sequence by a research programme that wanted a longer-acting analog without losing the full-length hormone's activity at its receptor. Instead of shortening the peptide or swapping many residues, the designers added a single hexenoyl group at the start of the chain, which protects the one position the DPP-4 enzyme attacks. That is a very different strategy from the heavily substituted shorter analogs, and it is part of why published findings on tesamorelin cannot simply be transferred to CJC-1295 or sermorelin. Our discovery and history article tells the story in full, and the preclinical article summarizes the models.
Why the full-length sequence matters
A full 44-residue sequence carries regions of the native hormone that the 29-residue fragments lack. In receptor-binding terms the first 29 residues carry most of the activity, but the remaining residues contribute to stability and to the molecule's overall behaviour in solution. This is one reason a certificate for tesamorelin should state measured purity and content for the whole chain, and why an impurity profile that shows many shortened forms is a warning sign.
Storage and handling
The compound is supplied as a lyophilized powder. General laboratory practice is to keep the sealed vial refrigerated, protected from light, heat and moisture, and to avoid repeated temperature cycling. Because GHRH-family peptides are prone to breakdown in solution, working solutions are best made fresh for each experiment. The reconstitution and storage article has the details, and the calculator guide helps with concentration arithmetic.
What V8 Peptides publishes for tesamorelin
We supply tesamorelin as a 10 mg research vial. A certificate of analysis from Accumark Labs is published for this product, with measured purity, content, endotoxin and PCR sterility results, and you can verify it on the laboratory's own site using the sample code printed on the report. It is on our COA page. For products that do not yet have a certificate, we say so on the product page.
Frequently asked questions
What does "tesa" mean?
It is community shorthand for tesamorelin, a synthetic analog of growth hormone-releasing hormone.
How is tesamorelin different from sermorelin and CJC-1295?
Tesamorelin is the full 44-residue GHRH sequence with a protective N-terminal hexenoyl group. Sermorelin is the 29-residue active fragment, and CJC-1295 without DAC is a modified 29-residue analog.
What does the hexenoyl group do?
It shields the peptide from the DPP-4 enzyme that would otherwise cleave its first two residues, which extends its duration of activity in published pharmacology.
Is research tesamorelin the same as the approved medicine?
No. The approved medicine is made by its originator under pharmaceutical controls. Research material is sold for laboratory use only, and nothing here is guidance for use in people or animals.
What should a tesamorelin COA show?
Lot code, test date, laboratory, measured HPLC purity with the chromatogram, identity, measured content, and endotoxin and sterility results.
Does V8 Peptides publish a COA for tesamorelin?
Yes, for the 10 mg lot, on the COA page. It can be verified on the laboratory's site.
How should the powder be stored?
General practice is refrigeration of the sealed vial, protected from light, heat and moisture, with working solutions made fresh.
Is this guide advice for use in people?
No. Tesamorelin from V8 Peptides is supplied for laboratory research only.
Where to go next
For a fuller picture of the compound, start with the tesamorelin research overview and the research FAQ. To check the certificates we publish, visit the COA page.
References
- Ferdinandi ES, et al. Non-clinical pharmacology and safety evaluation of TH9507, a human growth hormone-releasing factor analogue. Basic and Clinical Pharmacology and Toxicology. 2007;100(1):49-58.
- Falutz J, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. New England Journal of Medicine. 2007;357(23):2359-2370.
- Frohman LA, Jansson JO. Growth hormone-releasing hormone. Endocrine Reviews. 1986;7(3):223-253.
For laboratory research use only. Not for human or animal consumption. Not a drug, food or cosmetic. This article is educational and describes published research; it makes no claims about outcomes in people or animals.