What Are CagriSema and Retatrutide? How They Differ from Mounjaro

CagriSema and retatrutide are the weight-management drugs coming after Mounjaro, and both are still in research and regulatory review. Novo Nordisk’s CagriSema combines cagrilintide with semaglutide, while Eli Lilly’s retatrutide acts on three receptors, compared with Mounjaro’s two. As of August 2026, neither is legally available in Thailand.

What is CagriSema and how does it work?

CagriSema is a once-weekly subcutaneous injection from Novo Nordisk that combines two drugs in a single pen: cagrilintide 2.4 mg and semaglutide 2.4 mg. What draws attention to it is the addition of a new mechanism alongside the GLP-1 people are already familiar with.

Semaglutide is the same active ingredient used in the pens sold under the brand names Wegovy and Ozempic. It mimics the GLP-1 hormone the gut releases after eating, producing fullness sooner and slowing the emptying of the stomach. Cagrilintide is the new part of the equation. It is an analogue of amylin, a hormone the pancreas releases alongside insulin after a meal, which signals satiety to the brainstem through a pathway separate from GLP-1. Natural amylin breaks down very quickly, so cagrilintide was designed to stay in the body long enough for once-weekly injection.

Put simply, CagriSema tries to send two satiety signals at once, instead of relying on the GLP-1 pathway alone the way earlier drugs did. The idea resembles what Mounjaro does, combining more than one mechanism in a single injection. The difference is that Mounjaro pairs GLP-1 with GIP, while CagriSema pairs GLP-1 with amylin.

What is retatrutide, and how does it differ from earlier GLP-1 drugs?

Retatrutide (research code LY3437943) is a once-weekly subcutaneous injection from Eli Lilly that acts on three receptors within a single molecule, which is why it is called a triple agonist. The three receptors are GIP, GLP-1 and glucagon.

The first two are the same mechanisms Mounjaro uses. What is added is the glucagon receptor, and that is the point that clearly separates this drug from the existing class. Glucagon is the hormone the body releases when blood sugar runs low, and it is involved in drawing on stored energy. Stimulating that receptor in the context of a weight-management drug therefore targets the “energy expenditure” side of the equation, while GLP-1 and GIP work mainly on the “appetite and fullness” side.

Retatrutide’s phase-2 data was published in the New England Journal of Medicine in 2023, reporting that at week 48, 83% of participants on the 12 mg dose had lost 15% or more of their body weight, versus 2% in the placebo group (Jastreboff et al., NEJM 2023). It then moved into phase-3 studies under the TRIUMPH program, which reported results through 2026. These figures are group averages measured under research conditions, not numbers that can be used to predict an individual’s result.

How do CagriSema and retatrutide differ from Mounjaro?

The main differences come down to three things: the mechanisms each drug acts on, the company developing it, and, most importantly for any decision made today, approval status. Mounjaro is the only one of the three that is registered and in real-world use under a doctor’s supervision.

The key point this table makes is that the first two are research news, not treatment options that exist today. Anyone weighing a decision about their weight right now still has to choose primarily among medicines that are already registered.

What do the trial results report?

The information below consists of research findings, not promises about any individual user’s result. Every figure is an average across a group of participants selected by research criteria and measured under close monitoring by a research team.

On the CagriSema side, the main data comes from the phase-3 study REDEFINE 1, in 3,417 adults with overweight or obesity without diabetes, over 68 weeks, published in the New England Journal of Medicine (NEJM 2025). It reported average weight reduction of 20.4%, versus 3.0% in the placebo group; under the analysis assuming participants stayed on treatment as planned, the figures were 22.7% versus 2.3%. There is also REDEFINE 2, in 1,206 people with type 2 diabetes.

One point worth stating plainly is the REDEFINE 4 study, a head-to-head comparison of CagriSema against the 15 mg tirzepatide dose used in the trial, in 809 adults with obesity. At 84 weeks, the CagriSema group lost an average of 23.0%, versus 25.5% in the tirzepatide group (that was the dose used under research conditions; in practice a doctor titrates the dose for each person). That means the study did not meet its pre-specified non-inferiority threshold (Novo Nordisk press release, Feb 2026). The conclusion, then, is not that a newer drug automatically produces a bigger effect than an existing one.

On the retatrutide side, the TRIUMPH program reported three phase-3 studies in 2026:

• TRIUMPH-1 (May 2026), in 2,339 adults with obesity, or with overweight plus related health conditions. At 80 weeks, average weight reduction was 19.0% at the 4 mg dose, 25.9% at 9 mg and 28.3% at 12 mg, versus 2.2% in the placebo group.
• TRIUMPH-2 (Jul 2026), in 1,152 people who also had type 2 diabetes. At 80 weeks, average weight reduction ranged from 12.7% to 20.8% depending on dose, with average A1C reductions of 1.4–1.6% depending on dose.
• TRIUMPH-3 (Jul 2026), in 1,949 people with severe obesity together with cardiovascular disease. At 80 weeks, average weight reduction ranged from 21.6% to 22.6%.

Trial doses were administered under research protocols with monitoring by a medical team, not as self-dosing guidance.

Lining up figures from separate studies to ask “which one takes off more” is not a sound way to read the data, because each study used different populations, different durations and different methods of calculating the result. What can reasonably be said is that both drugs point in the same direction as the GLP-1 medicines already in use, and that each person’s actual result depends on their baseline health, the dose they can tolerate, and the behavioural changes that go with it.

What side effects were reported in the trials?

The side effects of both drugs fall in the same class as the GLP-1 medicines already in use, mainly gastrointestinal: nausea, vomiting, diarrhea, constipation and reduced appetite. They are most common when starting treatment or stepping the dose up, and tend to ease as the body adjusts.

In the TRIUMPH-1 study, the group receiving retatrutide 12 mg reported nausea in 42.4% versus 14.8% in the placebo group, diarrhea in 32.0% versus 13.5%, and 11.3% discontinued because of side effects versus 4.9%. This set of numbers matters just as much as the weight numbers, because it reflects the fact that a drug acting on several mechanisms at once also brings a side-effect burden that some users cannot tolerate. On the CagriSema side, most reported events were mild to moderate and decreased over time.

This class of medicine also carries specific contraindications and precautions, for example pregnancy or planned pregnancy, a history of pancreatitis, or a family history of certain thyroid cancers. That list is not exhaustive, and it is the reason these medicines must be started and titrated under a doctor’s supervision rather than adjusted by feel.

When will CagriSema and retatrutide reach Thailand?

The direct answer is that there is no set timeline, and it is too early to predict a date.

Novo Nordisk filed CagriSema for registration with the US Food and Drug Administration on 18 December 2025, and the company expects the review to conclude within 2026, which means that as of August 2026 the drug is still under review and not approved in any country. Eli Lilly has stated a plan to file retatrutide for registration with the US FDA in the first quarter of 2027, a plan that has not yet happened.

Even after an approval in the United States, reaching Thailand takes a further step: the manufacturer has to file for registration with Thailand’s Food and Drug Administration, which takes a different amount of time for each product, and no timeline has been announced for either of these drugs. Anyone who sees an advertisement naming a specific Thai launch date should treat it with suspicion.

Why you should not order unregistered drugs online

Because a drug that has not been approved in any country has no legitimate distribution channel anywhere, in Thailand or abroad. Whatever is offered for sale under the names CagriSema or retatrutide online, whether as a ready-filled pen, a vial of dry powder, or the label often used, “research peptide”, does not come from a production line anyone can trace.

The risks that follow come in layers. The substance may not be what it claims to be, the concentration may not match the label, storage and shipping may not be temperature-controlled, and the user has to reconstitute the drug and set the dose themselves, a step that goes wrong easily and with nobody monitoring for symptoms. These cases are nothing like receiving a registered medicine from a licensed medical facility, because when a side effect occurs there is neither reliable information about the substance nor anyone medically responsible.

The same checks that apply to spotting authentic injection pens apply here too, with one blunter addition: if a drug has not been approved anywhere in the world, there is no genuine version to buy in the first place. Common warning signs include:

• Sold without seeing a doctor and without any health history being taken
• Claims that it is a drug that “hasn’t reached Thailand yet” or was “carried in from abroad”
• Sold as a vial of powder for the buyer to mix, with vague dosing instructions
• No drug registration number or verifiable package insert
• Advertised with weight-loss figures achieved in implausibly short periods
• Sold through personal accounts or channels that are not medical facilities

What options exist in Thailand right now?

For anyone weighing a decision about their weight at the moment, the options that actually exist are the injectable GLP-1 medicines already registered with the Thai FDA, which a doctor selects according to the approved indications and each person’s health. Examples include tirzepatide, sold under the brand name Mounjaro, which acts on the GIP and GLP-1 receptors, and semaglutide, sold under the brand name Wegovy, which acts on the GLP-1 receptor. All of these are controlled medicines that must be prescribed and used under a doctor’s supervision.

Another development worth watching is the oral side, which is further along than the two injections in this article in terms of approval.

What determines a long-term result more than the name of the drug is the care plan as a whole: the health assessment before starting, periodic monitoring of progress and side effects, and a plan for eating habits after stopping. Results vary by individual. If you are interested in a doctor-supervised weight-management program at Onnyx Clinic, it always starts with a physician’s assessment. Mounjaro pens start at 2,499 THB; the clinic stocks 2.5 mg and 5 mg pens, as prescribed by the doctor. Consult a physician via LINE @onnyxclinic or call 092-789-0742.

Questions to ask your doctor before considering a new drug

When news about a new drug comes out, the useful question is not “which one takes off more” but the kind of question that connects the research to your own health. Try this set in the consultation room.

1. Does my health right now meet the criteria for using a weight-management medicine, or should I start with behavioural changes and screening for other causes?
2. Which of the medicines already registered in Thailand suits me better, given my existing conditions, the medicines I already take, and my allergy history?
3. What kind of study do the numbers in the news come from — was the study population similar to me, and at how many weeks was the result measured?
4. Which side effects am I likely to encounter, and what should I do if I do encounter them: stop the medicine, or adjust the dose?
5. What does the follow-up plan look like — what blood work or other tests are needed before starting and during treatment?
6. How should I plan for stopping, so that weight does not come back in a cycle?
7. What is the total cost across the whole care plan, since this is ongoing treatment rather than something done once?

The question to avoid is asking a doctor to prescribe a medicine that is not registered, because doctors cannot prescribe drugs that have not been approved, and a clinic willing to do it is a warning sign rather than a selling point.

References

• Coadministered Cagrilintide and Semaglutide in Adults with Overweight or Obesity — REDEFINE 1 (NEJM)
• Novo Nordisk press release: CagriSema filed for registration with the US FDA (18 Dec 2025)
• Novo Nordisk press release: REDEFINE 4 results comparing CagriSema with tirzepatide, which did not meet the study’s primary objective (23 Feb 2026)
• Triple–Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial (NEJM, 2023)
• Eli Lilly press release: phase-3 TRIUMPH-1 results for retatrutide (21 May 2026)
• Eli Lilly press release: phase-3 TRIUMPH-2 and TRIUMPH-3 results for retatrutide (23 Jul 2026)
• Thai Food and Drug Administration

This content is provided as general information, not a diagnosis or individual medical advice. The medicines discussed are prescription-only and must be used under a doctor’s supervision. Results vary by individual. Please consult a physician for an assessment appropriate to you.