Reference
How peptide drugs get their names
Semaglutide, tirzepatide, cagrilintide, tesamorelin, ipamorelin. Those endings are not decoration — they are a formal system, and once you can read it a name tells you what class a compound belongs to before you have looked anything up.
The stem system
Generic drug names are assigned through the International Nonproprietary Name programme, run by the World Health Organization. The scheme reserves word endings — stems — for particular classes, and a new compound in that class is given a name ending in the appropriate stem.
It exists so that a name is informative rather than arbitrary. The first part is chosen to be distinctive and pronounceable; the ending tells you what kind of thing it is.
The stems that matter here
-tide — peptides
The broad stem for peptides. Any generic name ending in -tide is telling you the molecule is a peptide, which is why so much of this range shares the ending. Most of the more specific stems below are refinements of it.
-glutide — GLP-1 receptor agonists
A narrower stem sitting inside -tide. Semaglutide carries it, as do liraglutide and dulaglutide, which you will meet in the same literature. The ending is the giveaway that they belong to one family.
-lintide — amylin analogues
Cagrilintide takes this one, as does pramlintide. It is a useful case, because cagrilintide is routinely discussed alongside the GLP-1 compounds — and its name says plainly that it is a different class. Amylin is not GLP-1.
-relin — hormone-release stimulating peptides
Both tesamorelin and ipamorelin carry it, which is a hint that they belong together — and they do, though they are built very differently. Sermorelin is another.
-melanotide — melanocortin receptor agonists
This is the one that explains a naming oddity in the range. PT-141 has the generic name bremelanotide, and Melanotan I is afamelanotide. Both carry the stem, which places them in the same family — and they are in fact chemically related, PT-141 having been derived from Melanotan II.
Why a compound has several names
The same molecule often travels under three or four names at once, and they are not interchangeable in what they tell you:
- A laboratory code. Assigned during development, usually a company or institution prefix and a number. SLU-PP-332 is one — SLU for Saint Louis University. So is PT-141, and so is CJC-1295.
- A generic name. Assigned formally, carries a stem, and is what appears in literature and on regulatory documents.
- A trade name. Owned by whoever markets it, chosen for commercial reasons, and carrying no information about the molecule at all.
A compound still going by a laboratory code and nothing else is telling you something: it has not been through the process of receiving a generic name, which usually means it is early in development or was never developed as a medicine.
The names that are not names
A handful of compounds are called by their own sequence. GHK is glycine-histidine-lysine; KPV is lysine-proline-valine. Those are not abbreviations of anything — they are the molecule written out in single-letter code.
Others take the name of the parent they were cut from, which is a reliable source of confusion. TB-500 is named for thymosin beta-4 and is not thymosin beta-4; BPC-157 is named for Body Protection Compound and is a fifteen-residue piece of it. A name that references a parent molecule is not a claim to be that molecule.
What a name does not tell you
The stem tells you a class. It says nothing about whether a compound is approved anywhere, what stage of development it reached, or what is in any particular vial. Retatrutide and semaglutide both end in -tide; one is an approved medicine in many countries and the other is investigational. The ending does not distinguish them.
