Retatrutide vs Mounjaro vs Ozempic
A clear comparison of retatrutide, tirzepatide and semaglutide: how they work, what clinical trials show, and what people researching these treatments in Thailand should know.
This page is for general education only. It does not provide medical advice, prescriptions, medication sales or treatment recommendations.
Quick overview
What is the main difference?
The main scientific difference is the receptor activity being studied. Semaglutide acts on the GLP-1 receptor. Tirzepatide acts on GIP and GLP-1 receptors. Retatrutide is being studied for activity across GIP, GLP-1 and glucagon receptors.
A medicine’s mechanism does not, by itself, show which option is best for a particular person. Approval status, evidence, risks, medical history and local availability all matter.
Retatrutide
A single molecule being studied as a triple hormone receptor agonist: GIP, GLP-1 and glucagon.
Mounjaro
The brand name for tirzepatide, a dual GIP and GLP-1 receptor agonist. Approved indications and product availability vary by market.
Ozempic
The brand name for semaglutide, a GLP-1 receptor agonist. Semaglutide is also marketed under other brand names for different indications in some markets.
Side-by-side
Retatrutide vs Mounjaro vs Ozempic
This table is a high-level educational overview, not a recommendation. Brand names, approved indications and prescribing rules differ by country.
| Topic | Retatrutide | Mounjaro / Tirzepatide | Ozempic / Semaglutide |
|---|---|---|---|
| General type | Investigational triple hormone receptor agonist | Dual GIP and GLP-1 receptor agonist | GLP-1 receptor agonist |
| Receptor activity | GIP, GLP-1 and glucagon | GIP and GLP-1 | GLP-1 |
| Current status | Under clinical development; not available for public use according to Lilly | Approved for specific uses in some markets; status varies by country | Approved for specific uses in some markets; status varies by country |
| Direct comparison evidence | A Phase 3 trial is comparing retatrutide with tirzepatide; results are not posted | Compared directly with semaglutide in the SURMOUNT-5 obesity trial | Compared directly with tirzepatide in the SURMOUNT-5 obesity trial |
| Thailand | Check current Thai regulatory information; online listings do not establish approval | Check current Thai approval, prescription and availability information | Check current Thai approval, prescription and availability information |
Retatrutide is the investigational molecule; “Mounjaro” and “Ozempic” are brand names. Products with the same active ingredient may have other brand names or approved indications.
Mechanism
Why retatrutide is different
Retatrutide is being studied as a “triple agonist” because one molecule activates receptors for GIP, GLP-1 and glucagon. Tirzepatide is commonly described as a dual agonist, and semaglutide as a GLP-1 receptor agonist.
GLP-1
GLP-1 receptor activity is studied in relation to appetite, blood glucose regulation and metabolic health.
GIP
GIP receptor activity is part of the dual-agonist mechanism of tirzepatide and the triple-agonist research on retatrutide.
Glucagon
Glucagon receptor activity is the additional pathway being studied with retatrutide compared with GLP-1-only medicines.
“GLP-3” is an informal and scientifically inaccurate label sometimes used online. “Triple agonist” is a more accurate description of the receptor activity being studied.
Clinical evidence
What have the trials reported?
Trial results describe groups of participants under defined study conditions. They are not a prediction of an individual’s result. The studies below differed in design and duration, so their percentages should not be ranked as if the medicines had been tested against one another in the same trial.
Retatrutide compared with placebo
This Phase 3 study enrolled adults with obesity or overweight and a weight-related health condition, without diabetes. In the published treatment-regimen analysis, average body-weight change was −17.6%, −23.7% and −25.0% for the 4 mg, 9 mg and 12 mg groups, compared with −3.9% for placebo.
Tirzepatide compared with semaglutide
In adults with obesity but without type 2 diabetes, average body-weight change was −20.2% with tirzepatide and −13.7% with semaglutide. This was a direct comparison of those two medicines, not retatrutide.
Retatrutide compared with tirzepatide
A registered Phase 3 study is designed to compare retatrutide and tirzepatide in adults with obesity. The trial registry does not currently list results.
The published TRIUMPH-1 report gives a 25.0% average change at 12 mg using its treatment-regimen analysis. Lilly has also reported 28.3% using a different analysis that estimates results if participants had continued treatment as intended. These are different statistical analyses; neither is a head-to-head comparison with Mounjaro or Ozempic.
How to read the evidence
Can we say which one works best?
Not by simply comparing numbers from separate studies. Results can be influenced by who took part, how long the study lasted, the doses tested, adherence, background care and the statistical analysis used.
SURMOUNT-5 provides a direct comparison between tirzepatide and semaglutide in a defined study population. TRIUMPH-5 is intended to provide a direct comparison between retatrutide and tirzepatide, but results are not yet posted.
A trial average cannot establish which medicine is suitable for an individual. Personal health history, current medication, possible risks, local approval and a clinician’s assessment all matter.
Safety and Thailand context
What should people in Thailand consider?
Lilly’s latest public information describes retatrutide as investigational and not available for public use. For any medicine, current approval, prescription rules and availability should be checked for Thailand rather than assumed from information about another country.
An online product listing does not confirm regulatory approval, product identity, quality or suitability. If discussing a treatment with a clinic, ask for clear information about the medicine, medical assessment and follow-up.
Ask about current status
Ask which active ingredient is being discussed and what its current regulatory status is in Thailand.
Ask about medical assessment
Ask what health history, current medicines and risk factors a qualified professional reviews before discussing treatment.
Ask about follow-up
Ask what monitoring and follow-up are available and how to get medical help if a problem occurs.
For general questions about evaluating clinics in Thailand, see Clinic Guidance.
Safety context
Side effects and medical supervision
Gastrointestinal symptoms such as nausea, vomiting, diarrhoea and constipation have been reported in retatrutide clinical research. Side effects can differ between participants and studies. Research findings are not a substitute for advice based on an individual’s health history.
Mounjaro and Ozempic also have medicine-specific warnings and possible side effects. Check the current prescribing information for the relevant country and indication. Do not start, stop or change a medicine based on this comparison page.
FAQ
Frequently asked questions
Is retatrutide the same as Mounjaro?
No. Mounjaro is a brand name for tirzepatide, which acts on GIP and GLP-1 receptors. Retatrutide is a different investigational molecule being studied for activity at GIP, GLP-1 and glucagon receptors.
Is retatrutide the same as Ozempic?
No. Ozempic is a brand name for semaglutide, which acts on the GLP-1 receptor. Retatrutide has a different receptor profile and remains investigational.
Is retatrutide more effective than Mounjaro or Ozempic?
A completed direct comparison of retatrutide with these medicines has not established that. Results from separate trials have different participants, study lengths and methods, so they should not be treated as a single ranking.
Has retatrutide been compared directly with tirzepatide?
A Phase 3 study called TRIUMPH-5 is designed to compare retatrutide with tirzepatide in adults with obesity. The trial registry does not currently list results.
Is retatrutide available for public use in Thailand?
Lilly currently describes retatrutide as investigational and not available for public use. Check current Thailand-specific information with relevant authorities and a qualified healthcare professional.
Why is retatrutide sometimes called a peptide?
Retatrutide is a synthetic peptide molecule, but “peptide” does not describe its approval status or confirm the identity or quality of a product sold online.
Sources and further reading
- Eli Lilly — What to know about retatrutide
- New England Journal of Medicine — TRIUMPH-1 retatrutide Phase 3 study
- New England Journal of Medicine — SURMOUNT-5 tirzepatide vs semaglutide
- ClinicalTrials.gov — TRIUMPH-5 retatrutide vs tirzepatide
- About Retatrutide
- Medical Disclaimer
Content reviewed: October 2026. Regulatory information may change.