Tesamorelin: What It Is and Why It Is a GHRH Analogue
Tesamorelin is a synthetic analogue of growth hormone-releasing hormone (GHRH), a 44-amino-acid signalling peptide, distinguished by a trans-3-hexenoyl group attached to its N-terminal tyrosine. It binds the GHRH receptor rather than the growth hormone receptor, and contains no growth hormone itself. It holds no approval from any medicines regulator, and is supplied for in vitro research purposes only.
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What Is Tesamorelin?
Tesamorelin is a synthetic 44-amino-acid analogue of growth hormone-releasing hormone (GHRH), studied in growth hormone axis research at the GHRH receptor. CAS 218949-48-5.
Human GHRH is a 44-residue peptide, and tesamorelin carries that same 44-residue sequence. The two are not identical molecules: tesamorelin differs at a single position, and every other residue in the chain is unchanged.
That difference is a trans-3-hexenoyl group attached to the N-terminal tyrosine. Unmodified GHRH is cleaved rapidly at that end by dipeptidyl peptidase-4; the added group makes tesamorelin markedly more resistant to the same enzyme in vitro. The receptor-binding region of the sequence is untouched.
Does It Contain Growth Hormone?
No. Tesamorelin contains no growth hormone at all, and this is the thing most often got wrong about it.
Tesamorelin is not growth hormone. The two are structurally unrelated, and they sit at different points on the same research axis:
- Growth hormone is a 191-amino-acid protein — the hormone itself.
- Tesamorelin is a 44-amino-acid GHRH analogue, studied at the GHRH receptor, one step upstream of it.
Compounds studied at this point on the axis are classed as secretagogues. It is worth knowing the word, because product listings often use it without explaining it.
Why Is Its Half-Life So Short?
Tesamorelin has a reported half-life of roughly eight minutes. Descriptions of it as long-acting are simply wrong.
That is a property of the design rather than a fault in it. The hexenoyl group buys resistance to enzymatic cleavage, not persistence in circulation, and the two are separate questions. Comparing it with a long-acting analogue compares two design choices, not a better molecule with a worse one.
So half-life on its own is a poor way to rank compounds in this class. It measures how long the molecule is present, not which receptor it was built to reach.
What Is the Published Record On It?
This is the single most important thing to understand about tesamorelin, and it is usually left out.
The published record on tesamorelin is narrow, and it is almost entirely clinical. It is not a broad literature spanning many settings, and none of it was gathered on material supplied for laboratory use. Read it as background on the molecule, not as evidence about a vial.
There is also almost no animal research on it, which is unusual. Most compounds in this catalogue have a large preclinical literature behind them and tesamorelin does not, so its record is thin in exactly the place the others are strongest.
What Have Regulators Said About It?
Two regulators reached opposite conclusions about tesamorelin, and both are worth knowing.
The United States registered it for a single, narrowly defined medical indication, under medical supervision. That registration covers a finished pharmaceutical product and not material supplied for laboratory use.
Europe did not register it. The application was submitted and then withdrawn while under review, and the assessment was never completed. Two regulators looking at the same dossier reached different conclusions, which is worth knowing before treating any registration status as settled.
In Australia the TGA’s position is that unapproved peptide products have not been assessed for safety, quality or effectiveness. In vitro research requirements covers what that means for a purchaser.
How Is Tesamorelin Different From CJC-1295 Without DAC and Ipamorelin?
Tesamorelin, CJC-1295 without DAC and ipamorelin are three separate molecules. None of them is growth hormone; all three are studied one step upstream of it, but two bind the GHRH receptor and the third binds a different receptor altogether.
| Compound | What it is | Signalling route described for it | Evidence that must stay attached to it |
|---|---|---|---|
| Tesamorelin | A stabilised analogue of growth-hormone-releasing hormone, or GHRH — the body’s own signal to the pituitary. The added chemical group shields it from the enzyme that would otherwise chop it up | Described as acting at the GHRH receptor on the pituitary | Its own research record, and the two regulatory decisions that followed from it, and nothing wider. That record is tesamorelin’s and belongs to no other compound in this table |
| CJC-1295 (no DAC) | A 29-amino-acid GHRH fragment carrying no DAC group, also catalogued as Modified GRF (1-29). ARP lists it inside a blend rather than on its own | Also described as acting at the GHRH receptor, which is why it and tesamorelin are grouped together | Its own no-DAC record, and only that. Figures reported for the DAC-modified form describe a different molecule of almost the same name, and they must not be carried across |
| Ipamorelin | A five-amino-acid peptide of the growth hormone secretagogue class, named after the receptor family that defines the class | Described as acting at the growth hormone secretagogue receptor, also called the ghrelin receptor. Both names refer to one protein, and it is not the GHRH receptor | Its own characterisation, which was done in animals. Because the receptor is a different one, nothing shown for a GHRH analogue transfers to it |
The naming trap sits on the middle row. Material sold as CJC-1295 comes in two forms whose published records are not interchangeable, and CJC-1295 with DAC and without works through how to tell which one a listing is describing.
What Do You Get When You Order It?
Australian Research Peptides supplies Tesamorelin as a freeze-dried powder in a sealed vial. Every batch is HPLC tested, and the certificate is published in the CoA library.
It is less stable once mixed than it is as a dry powder, so storage and handling matters more here than for most of the range.
Common Questions
No. Growth hormone is a 191-amino-acid protein; tesamorelin is a 44-amino-acid GHRH analogue and contains none of it. They are different molecules studied at different targets, which is why the two are never interchangeable on a listing.
Because the molecule is cleared quickly. The trans-3-hexenoyl group at the N-terminus protects it from dipeptidyl peptidase-4, but nothing in its design extends how long it persists, so a short half-life is expected rather than a defect.
No. They are three different molecules and they do not all bind the same receptor; two target the GHRH receptor and one does not. ARP groups them together under GHRH and secretagogue research, which is a catalogue heading rather than a claim that they behave alike.
Tesamorelin itself sits in the Australian Research Peptides catalogue as a single 10 mg vial under GHRH and Secretagogue Research, in stock and HPLC-tested with its certificate published, and goes out from Sydney to every Australian state and territory.
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