GLP-3: the nickname for retatrutide, a triple agonist
"GLP-3" (also spelled "GLP3" or "GLP 3"), "GLP-3 RT," "GLP-3 R"... This name circulates on social media and among vendors, but it's neither a hormone nor a new official class: it's a nickname for retatrutide, Eli Lilly's molecule that acts on three receptors simultaneously. Here's where the name comes from, what the trials show, and how to recognize genuine GLP-3.
Buy Retatrutide (GLP-3) 10 mg – €59.90Retatrutide (GLP-3) 20 mg – €99.90
The essentials
- GLP-3 = retatrutide(code LY3437943), developed by Eli Lilly. It is also called "R3", "Reta" or "R".
- There is no GLP-3 hormone: the number 3 refers to the three receptors that the molecule activates (GLP-1, GIP and glucagon).
- In phase 2, up to-24.2% average weight at 48 weeks(New England Journal of Medicine, 2023).
- It is an injectable peptide: it does not exist in capsule or spray form.
- Not yet authorized as a medicineEli Lilly plans to file with the FDA in the first quarter of 2027.
Why is it called "GLP-3"?
Obesity medications have varied in their targeting: semaglutide (Ozempic, Wegovy) activates a single receptor, GLP-1; tirzepatide (Mounjaro) activates two, GLP-1 and GIP; and retatrutide activates three: GLP-1, GIP, and glucagon. On social media, this "third stage" has become "GLP-3," a convenient but misleading abbreviation.
Biologically, the body produces GLP-1 and GLP-2 (two hormones derived from proglucagon), but no GLP-3. Therefore, the name does not refer to a hormone; it is a brand name for retatrutide. Its other names (R3, Reta, "the R"...) are explained on our page "What is R3? "
GLP-1, GLP-1/GIP and "GLP-3": the differences
| Molecule | Receptors | Nickname | Status in Europe |
|---|---|---|---|
| Semaglutide(Ozempic, Wegovy) | GLP-1 | "GLP-1" | Authorized medication, available by prescription |
| Tirzepatide(Mounjaro) | GLP-1 + GIP | "double agonist" | Authorized medication, available by prescription |
| Retatrutide | GLP-1 + GIP + glucagon | "GLP-3", R3, Reta | Not authorized (phase 3 completed) |
The glucagon receptor is what distinguishes retatrutide: it increases energy expenditure and promotes the use of fats, particularly those in the liver. For detailed information and pharmacy considerations, see R3: Is it a drug?
What clinical trials show
| Molecule | Trial | Duration | Average weight loss |
|---|---|---|---|
| Retatrutide (“GLP-3”) | Phase 2, Jastreboff et al., NEJM 2023 | 48 weeks | up to -24.2% (placebo -2.1%) |
| Tirzepatide | SURMOUNT-1, Jastreboff et al., NEJM 2022 | 72 weeks | up to -20.9% (placebo -3.1%) |
| Semaglutide | STEP 1, Wilding et al., NEJM 2021 | 68 weeks | -14.9% (placebo -2.4%) |
These trials do not have the same duration or the same participants: they do not constitute a direct comparison. The most frequent side effects of retatrutide aredigestives(nausea, diarrhea, vomiting), especially at the beginning of the trial, as with other molecules in the family. The phase 3 program (TRIUMPH) is complete; details of the dates are on our pageR3 medication.
GLP-3 in capsules, drops, spray or pen?
- Capsules, tablets, dropsRetatrutide is a peptide of 39 amino acids, which is destroyed by digestion. A "GLP-3" product that is swallowed is not retatrutide (often a dietary supplement that uses the same name).
- Nasal spray: no nasal form has been studied.
- Pen: no official pen exists; pens sold online are prepared by resellers (seeR3 by injection or pen).
- Freeze-dried bottle: the form of the research peptide, the only one whose content can be verified batch by batch.
"GLP-3 RT", "GLP-3 R", "GLP-3 Reta": the names on the labels
Because the name "retatrutide" is associated with Eli Lilly, many sellers label their bottles "GLP-3," "GLP-3 RT," "GLP-3 R," or "GLP-3 Reta." The label name proves nothing: only an independent certificate of analysis indicates whether the bottle actually contains retatrutide, at what purity, and in what quantity. Check three things:
- the identified molecule is indeed retatrutide (ideally by a blind test);
- the report has a number and a key that can be verified on the laboratory's website;
- the measured quantity is at least that of the label.
Our 7 Janoshik reports are published on the pageCOA of retatrutide.
Is GLP-3 legal in France and Europe?
Retatrutide has no marketing authorization in France or the European Union: no pharmacy dispenses it, and no doctor can prescribe it as a medication. Outside of clinical trials, it is sold only asresearch peptide, intended for laboratories. Country-by-country details are available on our pagelegality of retatrutide in Europe.
GLP-3 (retatrutide) price and analyzes
| Product | Content | Price | Price per mg |
|---|---|---|---|
| Retatrutide R3 10 mg | 1 lyophilized vial 10 mg | 59,90 € | 5,99 € |
| Retatrutide R3 20 mg | 1 lyophilized vial 20 mg | 99,90 € | 4,99 € |
| R10 Pack | Retatrutide 10 mg + reconstitution kit | 69,90 € | kit included |
| R20 Pack | Retatrutide 20 mg + reconstitution kit | 109,90 € | kit included |
Prices displayed without registration. Comparison with 12 European sellers:price of retatrutide in EuropeTo prepare a bottle:reconstitution calculator.
HPLC purity of 99.446% to 99.940% across 7 reports; measured quantity exceeds label level. Shipping €10, dispatched from the European Union.
Retatrutide R3 10 mg – €59.90Retatrutide R3 20 mg – €99.90
Frequently Asked Questions
What is GLP-3?
This is a nickname for retatrutide, a molecule from Eli Lilly that activates three receptors: GLP-1, GIP, and glucagon. There is no hormone called GLP-3; the 3 refers to the number of targets.
Are GLP-3 and retatrutide the same thing?
Yes. "GLP-3", "GLP-3 RT", "R3" or "Reta" all refer to retatrutide (LY3437943). Only an independent certificate of analysis confirms that a bottle labeled "GLP-3" actually contains it.
What is the difference between GLP-3, Ozempic and Mounjaro?
Ozempic (semaglutide) activates the GLP-1 receptor, Mounjaro (tirzepatide) activates both the GLP-1 and GIP receptors, and retatrutide activates the glucagon receptor. Ozempic and Mounjaro are approved medications; retatrutide is not yet approved.
Is GLP-3 available in capsules or spray?
No. Retatrutide is a peptide destroyed by digestion, and no nasal formulation has been studied. A "GLP-3" capsule is not retatrutide.
Where to buy GLP-3 in France?
It is not sold in pharmacies due to a lack of authorization. It exists only as a research peptide, sold online: MyPeptide offers retatrutide 10 mg for €59.90 and 20 mg for €99.90, with a Janoshik report per batch. We do not provide any dosage information.
When will GLP-3 be available in pharmacies?
Not before authorization: Eli Lilly plans to submit its application to the FDA in the first quarter of 2027. No application has been announced to the European Medicines Agency.
Sources: Jastreboff A.M. et al., N Engl J Med 2023 (retatrutide) and 2022 (tirzepatide, SURMOUNT-1); Wilding J.P.H. et al., N Engl J Med 2021 (semaglutide, STEP 1); Eli Lilly press releases 2026. MyPeptide products are intended for scientific research in the laboratory only.