Tesamorelin: research material vs the approved drug

The short answer

Tesamorelin is an approved prescription medicine in the United States, marketed as Egrifta. Material supplied as a research compound is not that product and carries none of its regulatory assurances. Identity rests on a 44-residue sequence carrying a distinctive N-terminal acyl group, at a mass near 5,136 Da.

An approved medicine, and a research chemical with the same name

Tesamorelin is unusual among compounds discussed in research-supply contexts: it is an approved drug. It received United States approval in 2010 and is marketed under the Egrifta name, with an indication in HIV-associated lipodystrophy supported by randomised, placebo-controlled human trials.

That approval attaches to a specific manufactured product made under pharmaceutical quality systems — not to the molecule in the abstract. Material sold as research tesamorelin is not the approved drug, was not made under those systems, and carries none of the assurances that approval represents.

Stating this plainly matters more here than for compounds with no approved counterpart, because the existence of a medicine by the same name invites exactly the wrong inference about what a research vial is.

What makes tesamorelin identifiable

Tesamorelin is a 44-amino-acid analogue of growth hormone-releasing hormone, distinguished from the natural sequence by a trans-3-hexenoyl group attached at the N-terminus. Its mass sits near 5,136 Da as the free base, and it is commonly supplied as an acetate salt.

The acyl modification is the identity anchor. Unmodified GHRH(1-44) lacks it, and sermorelin — a shorter GHRH(1-29) fragment — is a different length entirely. Both are plausible substitutions, and both differ from tesamorelin in total mass, so an intact-mass determination plus sequence confirmation separates them.

For a peptide of this size, that combination matters. Purity chromatography alone on a 44-residue molecule will not tell you whether the N-terminal modification is present; only a method that interrogates mass or sequence will.

What a tesamorelin certificate should carry

Expect identity confirmed against the modified 44-residue structure, with the method named. Expect purity by RP-HPLC reported against a specification, at a stated wavelength. For a salt-form peptide of this size, net peptide content and counterion content are particularly informative, because the gap between labelled mass and peptide mass can be substantial.

USP General Chapter ⟨1503⟩ sets out the attributes expected of synthetic peptide substances — identity, related substances, residual solvents, elemental impurities, water, counter-ion content, endotoxin and microbial limits. It is a reasonable benchmark for judging whether a certificate is complete or merely present.

As always, the lot on the certificate must match the lot on the vial, and the document should be verifiable with the issuing laboratory rather than only downloadable from the seller.

Size changes the analytical picture in ways worth noting. At 44 residues, tesamorelin is an order of magnitude larger than most peptides discussed alongside it, and larger molecules carry proportionally more scope for closely related impurities — truncated sequences, deletion variants, incomplete acylation — that sit near the target in both mass and chromatographic behaviour. This is precisely the territory USP ⟨1503⟩ addresses under related substances, and it is why a single purity number tells you less about a large peptide than it does about a five-residue one. The specification, and what it excludes, carries more of the meaning.

Questions researchers ask

Is research tesamorelin the same as Egrifta?

No. Egrifta is an approved pharmaceutical product manufactured under pharmaceutical quality systems and supported by clinical evidence. Research-supplied tesamorelin is not that product, regardless of sharing the molecule's name, and carries none of the regulatory assurances attached to the approved drug.

What molecular weight should tesamorelin show on a certificate of analysis?

Approximately 5,136 Da for the free base of the 44-residue sequence carrying its N-terminal hexenoyl group. Material is often supplied as the acetate salt, which is why counterion content and net peptide content are worth reading alongside the mass.

How do I tell tesamorelin apart from sermorelin on a COA?

By length and mass. Sermorelin is a GHRH(1-29) fragment — 29 residues — while tesamorelin is a modified 44-residue analogue. The two differ substantially in mass, so an intact-mass determination distinguishes them without ambiguity once identity is actually tested.

Does a tesamorelin COA need net peptide content?

It is strongly informative. For a large peptide supplied as a salt, counterion and residual water can account for a meaningful share of the powder's mass, so net peptide content tells you how much peptide is actually present where a purity percentage alone does not.

At a glance

Class: 44-residue GHRH analogue with N-terminal trans-3-hexenoyl group
Expected mass: ≈ 5,136 Da (free base; often supplied as acetate salt)
Confused with: Unmodified GHRH(1-44); sermorelin, GHRH(1-29)
Regulatory status: The molecule is approved as a medicine (Egrifta); research material is NOT that product
Use: Research use only — not for human or veterinary use

How our Tesamorelin lots test

Applying the same standard described above to our own material. Each certificate below opens on the issuing laboratory's portal— not a PDF hosted here — so you are reading the lab's record, not ours.

10mg · Lot XF703151 · 99.65% pureView verified COA ↗

Sources

Written from primary literature and published standards — never from other suppliers' marketing copy.

Written by Ivory Science. Scientific review: pending appointment of a named reviewer. Until then this page cites its sources directly so every claim can be checked at origin.

Tesamorelin in the catalogue All research notes How to judge a supplier

For research use only. Not for human or veterinary use, ingestion or administration. Nothing here is medical advice, and no statement on this page has been evaluated by the FDA. Tesamorelin is not an approved medicine.

Tesamorelin: research material is not the approved drug