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Research use only
· 7 min read
Native GHRH lasts minutes; evolution built it to fire a short pulse and vanish before the next one, so making it sit still is an act of quiet chemical defiance. Tesamorelin (developer code TH9507) is what happens when a medicinal chemist disagrees with that arrangement: a synthetic 44-amino-acid analogue of human growth hormone-releasing hormone, fitted with an N-terminal trans-3-hexenoyl group on the first tyrosine residue - a six-carbon modification whose sole job is to slow down the enzyme that would otherwise clip the peptide off at its N-terminus. Everything below describes what published studies have investigated, not any human use. Tesamorelin research reference material is supplied by Kovalabs strictly for laboratory investigation.
| Compound | Tesamorelin |
|---|---|
| Developer code / synonyms | TH9507 (TH-9507); GRF(1-44) analogue; growth hormone-releasing factor analogue |
| Class / mechanism | GHRH (GRF) receptor agonist; 44-residue GHRH analogue with N-terminal trans-3-hexenoyl modification |
| Molecular formula | C221H366N72O67S (free peptide) |
| Molecular weight | 5136 g/mol (PubChem, free peptide); 5135.9 Da free-base (FDA label; supplied as acetate salt) |
| CAS number | 218949-48-5 (free peptide); a salt-form registry (reported as 804475-66-9) is also in circulation |
| PubChem CID | 16137828 |
| InChIKey | QBEPNUQJQWDYKU-BMGKTWPMSA-N |
| UNII | MQG94M5EEO |
PubChem CID 16137828 is the reference record. The molecular formula is C221H366N72O67S, molecular weight approximately 5136 g/mol for the free peptide; the FDA label for the corresponding licensed product states the same formula and a free-base molecular weight of 5135.9 Da, noting that the material is supplied as an acetate salt. A reverse lookup of the InChIKey QBEPNUQJQWDYKU-BMGKTWPMSA-N independently resolves to the same CID, and the mass data are internally consistent (monoisotopic mass 5132.717, exact mass 5134.723). ChEBI (CHEBI:63626) records the same formula and CAS 218949-48-5, defining tesamorelin as a synthetic analogue of human GRF comprising the 44-amino-acid GRF sequence with a hex-3-enoyl moiety on the N-terminal tyrosine.
The identity trap here is the counter-ion. The compound is formulated and commonly registered as an acetate salt, and a salt-form CAS (reported as 804475-66-9) circulates alongside the free-peptide CAS 218949-48-5. Registries are not consistent on the acetate record, so quoting masses on the free-peptide basis is the safer convention; always state which basis you are using. Additional consistent identifiers include UNII MQG94M5EEO.
| Compound | Molecular class | Mode of action (as characterised) | Kovalabs research page |
|---|---|---|---|
| Tesamorelin (TH9507) | 44-residue GHRH (GRF 1-44) analogue, N-terminal hexenoyl | GHRH / GRF receptor agonist (in-vitro receptor binding) | View |
| CJC-1295 with DAC | Modified GHRH (GRF 1-29) analogue | GHRH / GRF receptor ligand | View |
| Sermorelin | GHRH (GRF 1-29) fragment analogue | GHRH / GRF receptor ligand | View |
| Ipamorelin | Pentapeptide secretagogue (distinct receptor class) | Ghrelin / GHS receptor ligand | View |
The target is the GHRH receptor - formally the GRF receptor, a seven-transmembrane-domain, Gs-protein-coupled receptor expressed on anterior-pituitary somatotroph cells. Tesamorelin is grouped by that receptor class, never by an indication. The FDA description characterises it as a GRF-receptor ligand at the in-vitro level; this is an in-vitro receptor-binding characterisation only, and no human effect is asserted.
The mechanistic literature on the GRF receptor itself is worth reading carefully. Mayo KE et al. (Recent Prog Horm Res, 1995; PMID 7740167) and Chen C et al. (Endocrine, 1998; PMID 9798733) characterise the receptor using cyclic AMP signalling as an endpoint, with a GRF-receptor antagonist as the specificity control - standard in-vitro assay design, not a statement about any compound in a living system. The downstream signal runs through Gs / cAMP / protein-kinase-A. A truncated splice variant of the receptor that cannot raise cAMP acts as a dominant-negative inhibitor by forming a complex with the wild-type isoform; isoform studies from Miller TL et al. (Endocrinology, 1999; PMID 10465288) and McElvaine AT and Mayo KE (Endocrinology, 2006; PMID 16423869) indicate that only the short receptor isoform signals through cAMP, with neither isoform mobilising intracellular calcium. These are receptor-mechanism studies; no effect of the Kovalabs reference material in any living system is asserted.
The trans-3-hexenoyl (C6) group on Tyr1 is a stability modification, and the rationale is purely physicochemical. Native GHRH is rapidly degraded by N-terminal cleavage from dipeptidyl-aminopeptidase enzymes; the hexenoyl group reduces susceptibility to that cleavage route. Appending a six-carbon acyl chain to the N-terminus is a well-precedented approach to extending resistance to exopeptidase attack, and it is described as such in the structural literature - not as evidence of any biological activity.
The registered clinical research base for tesamorelin runs across specific populations; the entries below are described by study design and named endpoint only. No result, magnitude, direction of change or benefit is reported or implied. Each disease-relevant endpoint is named neutrally for study-design context. Study design only; no effect is asserted for any of the above.
Re-check registry status and endpoint names at time of use. These records are listed as research context, not as findings a reader should expect.
The following are bench-chemistry considerations for a research reagent, not use instructions, and nothing here constitutes a preparation method for any use in humans or animals.
Tesamorelin reference material is handled as a lyophilised (freeze-dried) peptide powder. Standard peptide-reference guidance calls for storing the sealed lyophilate frozen - commonly at -20 C, extended to -80 C for long-term work - protected from light and moisture. Once reconstituted, the solution is held refrigerated at 2 to 8 C and, for longer bench storage, aliquoted to avoid repeated freeze-thaw cycles. The general procedure for reconstituting peptide reagents is documented in the Reconstitution guide; the standard approach is to add an appropriate laboratory solvent (an aqueous diluent or dilute acetic-acid solution) down the vial wall and mix by gentle swirling rather than vortexing, to limit shear stress on the peptide. Reconstituted solutions are used within a defined working window for analysis.
The molecule contains a methionine residue at position 27 (Met-27) that is its principal oxidation-sensitive site. That is the documented rationale for slightly acidic aqueous solvents, acetate-buffered conditions (around 20 mM acetate, pH near 5.0), avoidance of strong oxidising conditions and DMSO, and protection from light - all physicochemical stability measures for the reagent in the vial, not preparation guidance for any other purpose.
For a peptide reference material, the certificate of analysis is the document that substantiates identity and purity for a given lot. Relevant parameters include identity confirmation by mass spectrometry (MALDI-TOF or ESI-MS against the expected free-base mass near 5136 Da), sequence confirmation, and chromatographic purity by reverse-phase HPLC reported as a percent main-peak value. A vial that says tesamorelin and a vial that is tesamorelin are not the same assertion. Verifying the lot COA rather than relying on the label is the correct way to confirm a received reagent matches the stated molecule and grade; numeric windows vary between sources, so confirm against the actual lot document. Purity and identity should be verifiable rather than assumed.
Grouping here is by receptor class, not by indication. CJC-1295 with DAC and sermorelin are, like tesamorelin, GHRH (GRF) analogues that engage the GRF-receptor class, differing from tesamorelin in sequence length and modification: sermorelin covers only the first 29 residues of GRF, while CJC-1295 is a similarly truncated analogue with a Drug Affinity Complex modification for extended albumin binding. Ipamorelin represents a distinct molecular class - a pentapeptide that engages the ghrelin / growth-hormone-secretagogue (GHS) receptor rather than the GRF receptor, and is included here for receptor-class contrast. Shared axis membership does not imply shared receptor pharmacology. The full range is at GH-axis research peptides.
Tier one is solid: the chemistry is pinned down. PubChem CID 16137828, the InChIKey, ChEBI CHEBI:63626 and the FDA-label mass all converge on one 44-residue GRF analogue with a hexenoyl-modified N-terminus, and the free-peptide CAS is unambiguous once the acetate counter-ion is set aside. Tier two is the receptor work - cAMP-signalling and isoform assays at the GRF receptor (Mayo, Chen, Miller, McElvaine and Mayo). That mechanism is in-vitro characterisation; a cell in a dish is not a person, and binding a receptor is not an outcome. Tier three, the weakest, is what any of this means in living systems: the registered trials cited here are described by design and endpoint name only, with no result quoted, so the human picture stays open. It is not a licensed medicine, and it has not been shown to produce defined outcomes in humans. Curiosity is warranted; certainty is not.
Tesamorelin is supplied by Kovalabs as a research reference material for in-vitro and laboratory investigation by qualified professionals. It is not a medicine, not a supplement, and not for human or veterinary use. Nothing on this page describes a dose, a route, a schedule or an outcome. It has not been evaluated by the MHRA for safety or efficacy in humans or animals. Every batch ships with a certificate of analysis. Full terms are at the Research-use disclaimer.
Tesamorelin (developer code TH9507) is a synthetic 44-amino-acid analogue of human growth hormone-releasing hormone (GHRH, also called growth hormone-releasing factor, GRF 1-44), carrying an N-terminal trans-3-hexenoyl group on its first tyrosine residue. It is classified by its molecular pharmacology as a GHRH (GRF) receptor agonist. It is a research reference material only and is not for human or veterinary use.
PubChem CID 16137828, molecular formula C221H366N72O67S, molecular weight approximately 5136 g/mol for the free peptide (5135.9 Da free-base on the FDA label), InChIKey QBEPNUQJQWDYKU-BMGKTWPMSA-N, and UNII MQG94M5EEO. The unambiguous free-peptide CAS is 218949-48-5; a salt-form registry (reported as 804475-66-9) is also in circulation, so quote masses on the free-peptide basis. These were cross-checked by reverse InChIKey lookup and against ChEBI (CHEBI:63626) and found mutually consistent.
The trans-3-hexenoyl (C6) group on the N-terminal tyrosine is a stability modification. It reduces susceptibility to N-terminal cleavage by dipeptidyl-aminopeptidase enzymes, the route by which native GHRH is rapidly degraded. This is a physicochemical stability rationale described in the structural literature, not a statement about any effect or outcome.
Registered trials have been designed around named endpoints such as percent change in visceral adipose tissue by computed tomography, change in liver fat by magnetic resonance spectroscopy, insulin-like growth factor I (IGF-I), and pharmacokinetic parameters such as plasma clearance and volume of distribution. These are reported here by study design and endpoint name only. Study design only; no effect, magnitude or benefit is asserted, and these endpoints are listed purely as scientific context.
As a bench procedure for a research reagent: the lyophilised powder is generally stored sealed and frozen (commonly -20 C, and down to -80 C for extended periods), protected from light and moisture. Reconstitution involves adding an appropriate laboratory solvent down the vial wall and swirling gently rather than shaking, with reconstituted solution held refrigerated and aliquoted to avoid freeze-thaw cycles. The Met-27 residue makes the peptide oxidation-sensitive, hence slightly acidic, acetate-buffered conditions are appropriate. See Reconstitution guide and always confirm specifics against the lot certificate of analysis at Certificates of analysis.
This page makes no safety, efficacy or approval claim of any kind. Kovalabs supplies tesamorelin strictly as a research reference material for laboratory investigation by qualified researchers. It is for research use only and is not for human or veterinary use. Full terms are at Research-use disclaimer.