Yes. GLP-3, GLP-3 R, GLP-3 RT, GLP-3 RTA and GLP3-Reta all mean retatrutide, Eli Lilly's investigational triple agonist, still in phase 3 and approved nowhere.
There is no hormone called GLP-3. Your gut makes GLP-1 and GLP-2 and stops there. The number on a seller's listing counts drugs.
The rest of the pattern follows from that. GLP-2 T, GLP-2 TZ and GLP-2 TRZ mean tirzepatide, the drug in Mounjaro and Zepbound. GLP-1 S, GLP-1 SM and GLP-1 SG mean semaglutide, the drug in Ozempic and Wegovy. The letter after the number is the first letter of the drug, and that is the whole code.
If those names are new to you: semaglutide and tirzepatide are approved weight and diabetes drugs you can be prescribed. Retatrutide is neither approved nor prescribable anywhere, and that is why it only turns up in this market.
Is there a GLP-3 hormone?
No, and the term has spread far enough that Fox News ran an explainer on "GLP-3s" in January, describing it as an informal name for triple-agonist drugs and pointing at retatrutide.1
Seller pages get this wrong in both directions. One argues GLP-3 is a hypothetical third incretin hormone that science has not yet found, calling it a placeholder for a discovery not yet made, and concludes that retatrutide is therefore not GLP-3. Another states that GLP-3 RT is the name the World Health Organization assigned to the molecule, on a page where a find-and-replace has swapped the word retatrutide out of every sentence, leaving lines that say GLP-3 RT and GLP-3 RT are the same molecule.
The WHO assigned name is retatrutide. Lilly's development code is LY3437943.2 GLP-3 appears in neither. It is a sellers' shorthand, and it spread because it describes a real ladder. Semaglutide acts at one receptor, tirzepatide at two, retatrutide at three.
That coincidence is why the code feels more official than it is. The numbering follows the order the drugs arrived, and the receptor count happens to match. We also found GLP-1 T in the data. It means tirzepatide, and breaks the pattern entirely.
What does GLP-2 mean on a peptide site?
Tirzepatide, and this is the code that can actually mislead someone.
Glucagon-like peptide-2 is a real hormone, and there is a real medicine built on it. Teduglutide, sold as Gattex, was approved by the FDA in December 2012 for short bowel syndrome in adults, and extended to children in 2019. It is a once-daily injection that grows intestinal lining so patients can absorb more of what they eat and depend less on intravenous feeding.3 It has nothing to do with weight.
A peptide seller's GLP-2 is not that. On every page in our September snapshot where the seller added a letter, GLP-2 meant tirzepatide. Where no letter was added, the vial sizes and the retatrutide and semaglutide listings on the same site point the same way.
If you searched for the GLP-2 drug your doctor mentioned and landed in a peptide shop, you are looking at the wrong compound. Someone shopping for tirzepatide who finds a GLP-2 listing has found what they expected, from a seller who named it after something else entirely.
What does GLP-1 S mean?
Semaglutide, the compound in Ozempic and Wegovy. SM, SMA and SG are the same thing, with SMA reading as semaglutide analog.
A vial coded GLP-1 S is not Ozempic or Wegovy. Those are specific products made and labelled by their manufacturer. A coded vial is powder from a seller, with no approval of its own.
GLP-1, GLP-2 and GLP-3 codes: the full decoder
Every variant here appeared on at least one tracked seller's product page in our 23 September 2026 snapshot, across 6,774 listings from 133 sellers. Counts are of sellers rather than of products. A seller using two spellings is counted under each, and the numbers are a floor: sellers we do not track, and listings that changed after that date, are not in it.4
| On the listing | Means | Sellers |
|---|---|---|
| GLP-1 S, GLP-1 (S), GLP1-S | Semaglutide | 15 |
| GLP-1 C | Cagrilintide, an amylin analog rather than an incretin drug5 | 2 |
| GLP-1 C/S | Cagrilintide plus semaglutide, sold as a blend5 | 1 |
| GLP-1 SM, GLP-1 (SM) | Semaglutide | 8 |
| GLP-1 SG, GLP1-SG | Semaglutide | 4 |
| GLP-1 SMA | Semaglutide | 2 |
| GLP-1 AL (S) | Semaglutide, AL for analog | 1 |
| Sema, SEMA-10, SEMA-20 | Semaglutide | 4 |
| GLP-2 T, GLP-2 (T), GLP2-T | Tirzepatide | 11 |
| GLP-2 TZ, GLP-2 (TZ) | Tirzepatide | 6 |
| GLP-2 TRZ, GLP-2 (TRZ), GLP-2 (TR) | Tirzepatide | 4 |
| GLP-2 AL (T) | Tirzepatide | 1 |
| GLP-1 T | Tirzepatide, spelled out by one seller as GLP-1 plus GIP | 3 |
| Tirz, TIRZ-30, TIRZ-60, TIRZ-120 | Tirzepatide | 11 |
| GLP-3 R, GLP-3 (R), GLP3-R | Retatrutide | 17 |
| GLP-3 RT, GLP-3 (RT), GLP3-RT | Retatrutide | 11 |
| GLP-3 RTA | Retatrutide, A for analog | 1 |
| GLP-3 AL (R) | Retatrutide | 1 |
| Reta, RETA-10, RETA-20, GLP3-Reta | Retatrutide | 11 |
| DA-T (GLP-2), TA-R (GLP-3) | One seller's own scheme for tirzepatide and retatrutide | 1 |
| GLP-2 with no letter | Not stated on the page. Every seller using it lists retatrutide and semaglutide separately, so the bare GLP-2 is the missing third drug, tirzepatide. The listing does not say so | 4 |
| GLP-3 with no letter | Not stated on the page. The same sellers list GLP-2 beside it | 3 |
The table is a snapshot from one date. The live lookup at /names carries every name in the library, including these codes, with a current count of tracked sellers using each spelling.
GLP-1 C breaks the pattern, and two sellers say so themselves. It is cagrilintide, an amylin analog, and GLP-1 C/S is cagrilintide sold with semaglutide as a blend, which is the pairing behind CagriSema.5 Neither is a GLP-1 drug, so the code here labels the shelf rather than the mechanism.
One code is still unresolved: GLP-1 R, from one seller, whose page does not say. If you are holding that one, the certificate of analysis has to name the compound before the code means anything.
The number in a coded listing is how many milligrams are in the vial. GLP-3 RT 30mg is a 30 mg vial of retatrutide powder.
How many sellers use these codes?
Fifty-three of the 133 we track, enough that a keyword search misses most of the market.
Thirty-one of those 53 code all three drugs, and the pattern holds across sellers with no visible connection to each other.4
That cuts both ways for a buyer. Searching a seller's site for retatrutide will miss any listing that never says retatrutide, and searching for GLP-3 on a site that spells the drug out will turn up nothing at all.
Do coded listings cost less?
Not in any way that survives a look at the numbers.
The theory is reasonable: a coded listing is harder to find, so it might be priced to move. In the August capture, retatrutide sold under a code ran at a median of $6.50 per mg against $7.56 for listings using the drug's name. That looks like a discount until you notice the coded figure comes from 10 sellers and the named one from 17, so the gap is as likely to be which shops use codes as what codes do to price.
Tirzepatide and semaglutide show nothing at all. Coded tirzepatide ran $5.15 per mg against $4.90 named, and coded semaglutide $7.88 against $8.00, both from a handful of listings.4
The code is a naming choice and nothing more. When you compare prices, compare across both spellings, because a site that codes its listings will not appear in a search for the drug's name.
Does the code tell you what is in the vial?
Nothing that a name would not, and slightly less.
A certificate of analysis for a coded product still has to identify the compound. If the certificate says GLP-3 and nothing else, it has identified nothing, because no reference standard exists under that name. Our guide on reading a COA covers what a usable one contains.
The code also changes nothing about legal status. In June 2026 the FDA stated that selling unapproved retatrutide to consumers is illegal and that it cannot lawfully be compounded, and on 12 August 2026 Lilly filed six lawsuits against US businesses it accuses of selling it, saying it had reported more than 14,000 listings, adverts and posts to platforms and payment companies.67 A listing that says GLP-3 RT is a retatrutide listing in every sense a regulator cares about.
Semaglutide and tirzepatide are approved drugs. The approved products are Ozempic, Wegovy, Mounjaro and Zepbound. A coded vial is none of those.
How do you find the drug behind the code?
If you searched a code and want the drug behind it, the pages are here: semaglutide, tirzepatide, retatrutide. Each has the doses that trials or the approved label actually used, the price table across tracked sellers, the published record and what regulators have said.
For a code that is not one of these three, or a research code, brand name or nickname for any other compound, the names lookup covers all of them and says which compound each one refers to.
If you searched a drug name and cannot find it on a seller's site, try the code. Sellers who use codes use them consistently within one shop, so a site listing GLP-3 RT will list GLP-2 TRZ and GLP-1 SM alongside it.
Common questions
Is GLP-3 the same as retatrutide?
Yes. GLP-3, GLP-3 R, GLP-3 RT and GLP-3 RTA are all sellers' shorthand for retatrutide, Eli Lilly's investigational triple agonist, development code LY3437943.
What is GLP-3?
A seller's code for retatrutide. It is neither a hormone nor a drug class. On a peptide site, GLP-3, GLP-3 R, GLP-3 RT and GLP3-Reta all point at the same investigational triple agonist from Eli Lilly.
What is the difference between GLP-2 and GLP-3 on a peptide site?
GLP-2 means tirzepatide and GLP-3 means retatrutide. The numbers count drugs in the order they arrived, not hormones, and the letter after the number is the drug's initial.
Is GLP-3 a real hormone?
No. The body makes GLP-1 and GLP-2. There is no human GLP-3, and no drug class by that name. Pages claiming GLP-3 is an undiscovered third incretin are describing a hypothesis about biology, while the vial in front of you holds retatrutide.
Is GLP-1 C cagrilintide?
Yes. Two sellers name it on their own product pages, and one sells GLP-1 C together with GLP-1 S as a cagrilintide and semaglutide blend. Cagrilintide is an amylin analog, so this is the one code in the set that does not label a GLP-1 drug at all.
Is GLP-3 R the same as GLP-3 RT?
Yes, in every case we found. R, RT and RTA are three ways of shortening retatrutide. The A stands for analog and is not a different molecule.
What does GLP-2 mean on a peptide website?
Tirzepatide, on every tracked page where the seller added a letter to say which drug it meant.
Is the GLP-2 on a peptide site the same as the GLP-2 drug my doctor mentioned?
Almost certainly not. The approved GLP-2 medicine is teduglutide, sold as Gattex, for short bowel syndrome. It grows intestinal lining and has nothing to do with weight.
What does GLP-1 SMA mean?
Semaglutide. SM, SMA and SG all shorten semaglutide, and SMA reads as semaglutide analog.
Does the number mean how strong it is?
No. It follows the order the drugs became well known, and it happens to match how many receptors each one hits. It says nothing about strength, and the milligram figure on the vial is how much powder the vial holds.
Why do sellers use codes instead of drug names?
They do not say. What can be observed is that a listing coded GLP-3 RT does not appear in a search for retatrutide, and that Lilly has been reporting retatrutide listings to platforms by the thousand.
Are coded listings cheaper?
No, or not reliably. In the August capture, coded retatrutide ran about a dollar per mg below named listings, but from a smaller set of sellers, and coded tirzepatide and semaglutide showed no difference at all. The code is a naming choice and nothing more.
Will a price table find a coded listing?
When the seller's own page confirms which compound it is, yes, and it appears in that compound's price table. A listing giving only a code and nothing else is not matched, because matching it would be a guess. You can check any code against the names lookup first.
Sources
- Fox News. "What are GLP-3s? Meet the new generation of weight-loss drugs with three key ingredients", 12 January 2026. [foxnews.com](https://noticias.foxnews.com/health/what-glp-3s-meet-new-generation-weight-loss-drugs-three-key-ingredients.print). *National news explainer, read via search results. Describes GLP-3 as an informal term for triple-agonist drugs targeting GLP-1, GIP and glucagon receptors, with retatrutide as the most advanced example. Cited to show the term has spread beyond seller catalogues.* ↩
- Sport Integrity Australia. Retatrutide substance education page, listing LY-3437943 and "Reta" as other names. [sportintegrity.gov.au](https://www.sportintegrity.gov.au/what-we-do/anti-doping/substance-education/retatrutide). *Government anti-doping education page, read via search results. Used for the WHO assigned name and the development code, which is the specific claim two seller pages get wrong.* ↩
- Takeda. Gattex (teduglutide), FDA approval December 2012 for short bowel syndrome in adults, extended to children aged 1 and older in May 2019. [takeda.com](https://www.takeda.com/en-us/newsroom/news-releases/2019/us-fda-approves-gattex-teduglutide-for-children-1-year-of-age-and-older-with-short-bowel-syndrome-sbs/). *Manufacturer announcement, read via search results, corroborated by the FDA approval reporting at the time. Establishes that a real approved GLP-2 medicine exists and what it treats, which is the point of the teduglutide section.* ↩
- Peptide Decoding vendor price snapshot, 23 September 2026. [peptidedecoding.com/prices](https://peptidedecoding.com/prices). *The site's own tracker: 6,774 listings across 133 sellers. Seller counts in the decoder are distinct sellers whose product name contained the code, counted by regex per code family, so families overlap where a seller uses two spellings. Re-run before publishing, since the weekly capture moves these numbers.* ↩
- Seller product pages identifying GLP-1 C, read 24 September 2026. *Two sellers name the compound themselves: one lists GLP-1 C as cagrilintide, and another sells GLP-1 C together with GLP-1 S described as a cagrilintide and semaglutide blend. Seller names and URLs are recorded in the build notes rather than published here.* ↩
- Eli Lilly and Company. Lilly calls on online platforms, payment companies and regulators to shut down the illegal retatrutide black market, 12 August 2026. [investor.lilly.com](https://investor.lilly.com/news-releases/news-release-details/lilly-calls-online-platforms-payment-companies-and-regulators). *Company announcement about its own product. Source for the six lawsuits and the figure of more than 14,000 referrals to platforms.* ↩
- CNBC. Lilly sues six companies over alleged illegal sales of experimental obesity drug retatrutide, 12 August 2026. [cnbc.com](https://www.cnbc.com/2026/08/12/lilly-lawsuits-obesity-drug-retatrutide.html). *News report, read via search results. Source for the FDA's June 2026 statement that sales of unapproved retatrutide to consumers are illegal and that it cannot lawfully be compounded.* ↩