Tesamorelin is a synthetic analog of growth hormone-releasing hormone (GHRH), the hypothalamic peptide that signals the pituitary gland to release growth hormone. It is one of the few compounds in the growth hormone secretagogue category that has reached regulatory approval, which makes it a useful reference point for anyone studying the GHRH axis. PRIME supplies tesamorelin strictly as a research material for laboratory use.
What is tesamorelin?
Tesamorelin is a 44-amino-acid peptide built on the full sequence of human GHRH. Its defining modification is a trans-3-hexenoyl group attached to the N-terminal tyrosine. Native GHRH is broken down quickly in circulation, largely by the enzyme dipeptidyl peptidase-4 (DPP-4), which removes the first two amino acids and inactivates the hormone. The N-terminal modification in tesamorelin was designed to make the molecule more resistant to that cleavage while keeping its ability to bind and activate the GHRH receptor.
In the United States, tesamorelin is FDA-approved under the brand name Egrifta for a specific indication related to HIV-associated lipodystrophy. That approval applies to the finished pharmaceutical product only. Research-grade tesamorelin sold for laboratory work is not a medicine, is not intended for human use and is not a substitute for any approved drug.
Within the wider family of growth hormone secretagogues, tesamorelin sits alongside other GHRH analogs such as CJC-1295, and it is often contrasted with ghrelin-receptor agonists such as ipamorelin, which reach a similar downstream endpoint through a different receptor.
How tesamorelin works: mechanism studied in research
Tesamorelin acts as an agonist at the GHRH receptor (GHRH-R), a G protein-coupled receptor expressed on somatotroph cells of the anterior pituitary. Binding to this receptor activates adenylyl cyclase and raises intracellular cyclic AMP, which in turn drives both the synthesis and the release of growth hormone. Because it works through the natural GHRH pathway, its effect has been described in research as preserving the pulsatile pattern of growth hormone secretion rather than replacing it with a constant signal.
Downstream, growth hormone stimulates the liver and other tissues to produce insulin-like growth factor 1 (IGF-1), so studies involving tesamorelin commonly track both growth hormone and IGF-1 as markers. The GHRH pathway also remains subject to the normal negative feedback provided by somatostatin and by IGF-1 itself. Researchers often highlight this point when comparing GHRH analogs with direct administration of growth hormone in experimental designs, since the analog works upstream and leaves the body's regulatory loop in place.
A key contrast in the literature is with ghrelin mimetics. Ipamorelin and related compounds act on the growth hormone secretagogue receptor (GHS-R1a) rather than on GHRH-R. The two receptor pathways are distinct, which is why studies sometimes examine them separately, or together, to understand how they interact at the level of the pituitary.
Areas of research
- Visceral adipose tissue: tesamorelin has been investigated in clinical trials focused on abdominal fat accumulation in people with HIV-associated lipodystrophy, which formed the basis of its approval.
- Hepatic fat: it has been studied in research examining liver fat content and related metabolic markers.
- GH/IGF-1 axis physiology: as a stabilized GHRH analog, it is used as a tool to probe pituitary somatotroph function and feedback regulation.
- Cognition and aging: the GHRH pathway has been explored in studies of cognitive function in older adults, with tesamorelin among the analogs investigated.
- Body composition and lipid metabolism: studies have examined lipid parameters and measures of lean and fat mass as secondary outcomes.
Findings in one population or model do not transfer automatically to other settings, and research-grade material carries no approved use of any kind.
Tesamorelin key facts
| Property | Detail |
|---|---|
| Compound class | Synthetic GHRH analog (growth hormone secretagogue) |
| Structure | 44-amino-acid peptide based on human GHRH, with an N-terminal trans-3-hexenoyl modification |
| Primary target | GHRH receptor on anterior pituitary somatotrophs |
| Form supplied | Lyophilized powder in a sealed vial |
| Research status | FDA-approved as Egrifta for a specific indication; research-grade material is for laboratory use only |
| Storage | Lyophilized: refrigerated or frozen, protected from light and moisture. Reconstituted: refrigerated |
Handling and storage in the lab
Like most research peptides, tesamorelin is shipped as a lyophilized (freeze-dried) powder, which is the most stable form for transport and storage. Unopened vials are best kept refrigerated, or frozen for longer-term storage, away from direct light and moisture. Allow a cold vial to reach room temperature before opening it to limit condensation inside the vial.
For laboratory work, lyophilized peptides are commonly reconstituted with bacteriostatic water, a sterile water containing a small amount of benzyl alcohol as a preservative. Standard practice is to add the diluent slowly down the inside wall of the vial and swirl gently rather than shake, since vigorous agitation can damage peptide structure. Once reconstituted, the solution should be kept refrigerated, protected from light and used within the stability window appropriate to the experiment. Label each vial with the compound, concentration and date of reconstitution, and avoid repeated freeze-thaw cycles, which can degrade peptides over time.
Work with appropriate personal protective equipment and follow your institution's procedures for handling, recording and disposing of research chemicals.
Quality and lab results
Consistency matters in any study that relies on a peptide reagent. Every batch of tesamorelin sold by PRIME is tested by an independent laboratory, and the certificate of analysis for each lot is published on our lab results page. A COA typically confirms the identity of the compound and reports its purity as measured by analytical methods such as HPLC and mass spectrometry. We recommend checking the COA that matches your batch before beginning any experiment and keeping a copy with your lab records.
Research-grade material is available on the tesamorelin product page, where vial size and current batch information are listed.
Related research
- Ipamorelin vs tesamorelin: a side-by-side look at a GHRH analog and a ghrelin-receptor agonist.
- CJC-1295 no DAC research guide: another modified GHRH analog that is often discussed next to tesamorelin.
- Ipamorelin research guide: the selective GHS-R1a agonist frequently studied alongside GHRH analogs.
Tesamorelin FAQ
Is tesamorelin a peptide?
Yes. Tesamorelin is a 44-amino-acid synthetic peptide based on the sequence of human growth hormone-releasing hormone, with a chemical modification at the N-terminus intended to improve its stability against enzymatic breakdown.
Is tesamorelin FDA approved?
Tesamorelin is FDA-approved in the United States under the brand name Egrifta for a specific indication related to HIV-associated lipodystrophy. Research-grade tesamorelin sold for laboratory use is a separate product, is not a drug and is not intended for human consumption.
What is the difference between tesamorelin and CJC-1295?
Both are GHRH analogs that act on the GHRH receptor. Tesamorelin uses the full 44-amino-acid GHRH sequence with an N-terminal hexenoyl group, while CJC-1295 no DAC is based on the shorter 1-29 fragment of GHRH with several amino acid substitutions. The two were designed with different approaches to stability, which is why researchers compare them.
How is tesamorelin different from ipamorelin?
Tesamorelin works through the GHRH receptor, while ipamorelin is a ghrelin mimetic that acts on the growth hormone secretagogue receptor (GHS-R1a). Both have been studied for their influence on growth hormone release, but they use separate receptor pathways and are often studied for how those pathways interact.
How should tesamorelin be stored in the lab?
Keep lyophilized vials refrigerated or frozen, sealed and away from light. After reconstitution with bacteriostatic water for lab use, keep the solution refrigerated, protect it from light and avoid repeated freeze-thaw cycles.
For laboratory research use only. Not for human consumption. Not a drug, food or cosmetic.