On the trial data available as of mid-2026, retatrutide produces more weight loss than CagriSema. Eli Lilly's retatrutide hit 28.3% mean weight reduction at the top dose in its first pivotal phase 3 obesity trial, while Novo Nordisk's CagriSema reached 22.7% in REDEFINE 1 under its most favorable analysis. Retatrutide is further behind on the regulatory path, though, so the practical answer depends on whether you care about peak efficacy or actual availability.
This comparison is between two very different molecules. CagriSema is a fixed-dose combination of two peptides. Retatrutide is a single molecule that hits three receptors at once. Below is what the published trials actually show, where the headline numbers come from, and the caveats that get lost in marketing.
Quick answer: the head-to-head numbers
There has been no direct trial pitting CagriSema against retatrutide. Any comparison is cross-trial, meaning different patient populations, durations, and analysis methods, so treat the gap as directional rather than exact.
| Feature | CagriSema | Retatrutide |
|---|---|---|
| Maker | Novo Nordisk | Eli Lilly |
| Drug class | Amylin analog + GLP-1 (combination) | GIP/GLP-1/glucagon triple agonist |
| Components | Cagrilintide 2.4 mg + semaglutide 2.4 mg | Single molecule |
| Dosing | Once weekly injection | Once weekly injection |
| Top weight loss | 22.7% (REDEFINE 1, on-treatment) | 28.3% (TRIUMPH-1 phase 3, 12 mg) |
| Phase 2 / earlier signal | 20.4% treatment-policy estimand | 24.2% at 48 weeks (phase 2, 12 mg) |
| Trial population | Adults with obesity, no diabetes | Adults with obesity, no diabetes |
| Status (2026) | Filed with FDA, not approved | Investigational, phase 3 ongoing |
What CagriSema is and how it works
CagriSema combines two injectable peptides in one pen. The first is semaglutide, the GLP-1 receptor agonist already sold as Wegovy and Ozempic. The second is cagrilintide, a long-acting analog of amylin, a hormone the pancreas releases alongside insulin. Amylin slows gastric emptying and promotes satiety through a pathway that is separate from GLP-1, so the theory is that the two together suppress appetite more completely than either alone.
The REDEFINE 1 data supports that additive logic. Over 68 weeks, participants on CagriSema lost 20.4% of body weight, compared with 11.5% for cagrilintide alone, 14.9% for semaglutide alone, and 3.0% for placebo (treatment-policy estimand). The combination clearly beat its individual parts.
Both components are dosed at 2.4 mg once weekly after titration. That makes CagriSema a once-weekly subcutaneous injection, the same cadence patients already know from Wegovy.
What retatrutide is and how it works
Retatrutide is a single peptide that activates three receptors: GIP, GLP-1, and glucagon. The first two overlap with tirzepatide (Mounjaro and Zepbound), which is why retatrutide is often described as "tirzepatide plus glucagon." The glucagon arm is the differentiator. Glucagon receptor activation increases energy expenditure and supports fat metabolism in the liver, adding a mechanism that the GLP-1 and GIP arms do not provide on their own.
For a deeper breakdown of the receptor pharmacology, see our guide to the retatrutide mechanism of action and the overview of what retatrutide is. The triple-agonist design is the central reason its weight-loss numbers run ahead of dual agonists and amylin combinations.
Retatrutide is also a once-weekly injection, titrated up over several weeks to reduce gastrointestinal side effects. Our retatrutide dosing schedule walks through the escalation used in the trials.
The efficacy data, side by side
CagriSema: REDEFINE 1 and REDEFINE 2
REDEFINE 1 enrolled 3,417 adults with obesity or overweight without type 2 diabetes and ran for 68 weeks. The results, published in the New England Journal of Medicine and presented at the American Diabetes Association meeting in June 2025, came in two flavors:
- On-treatment (treatment adherence) estimand: 22.7% mean weight loss versus 2.3% for placebo
- Treatment-policy estimand (regardless of adherence): 20.4% versus 3.0%
Among adherent participants, 97.6% lost at least 5%, 60.2% lost at least 20%, 40.4% lost at least 25%, and 23.1% lost at least 30%. Just over half (50.7%) dropped below the obesity BMI threshold.
The headline that dominated coverage was disappointment. Novo Nordisk had guided toward roughly 25% weight loss, and CagriSema fell short of that internal target, which moved the company's share price. The drug works well by any historical standard. It just did not clear the bar investors expected.
REDEFINE 2 tested CagriSema in 1,206 adults who also had type 2 diabetes, again over 68 weeks. Weight loss was lower, as it usually is in patients with diabetes: 15.7% on the adherence estimand and 13.7% on the treatment-policy estimand.
Retatrutide: phase 2 and the first phase 3 readout
Retatrutide's phase 2 obesity trial randomized 338 adults and ran 48 weeks. At the 12 mg dose, mean weight loss was 24.2% versus 2.1% for placebo, with 17.5% already reached by 24 weeks. By week 48, 83% of the 12 mg group had lost at least 15% of their starting weight. Those figures, published in NEJM in 2023, are what put retatrutide on the map. You can read more in our retatrutide clinical trial summary.
The phase 3 TRIUMPH-1 trial, with topline results reported in 2026, scaled that up. It randomized 2,339 participants with obesity (no diabetes) across four arms and measured weight change at 80 weeks:
- 4 mg: 19.0% (about 47.2 lb)
- 9 mg: 25.9% (about 64.4 lb)
- 12 mg: 28.3% (about 70.3 lb)
- Placebo: 2.2% (about 5.5 lb)
At the 12 mg dose, 62.5% of participants lost at least 25% of body weight, 45.3% lost at least 30%, and 27.2% lost at least 35%. Those response rates are higher than anything reported for CagriSema or for approved dual agonists.
Side-by-side weight-loss comparison
| Metric | CagriSema (REDEFINE 1) | Retatrutide (TRIUMPH-1, 12 mg) |
|---|---|---|
| Mean weight loss | 22.7% (on-treatment) | 28.3% |
| Treatment-policy / ITT figure | 20.4% | reported as topline |
| Reached at least 25% loss | 40.4% | 62.5% |
| Reached at least 30% loss | 23.1% | 45.3% |
| Placebo comparator | 2.3% to 3.0% | 2.2% |
| Trial population | No type 2 diabetes | No type 2 diabetes |
Even allowing for cross-trial noise, the pattern is consistent: retatrutide's top dose moves more weight and gets a larger share of patients into the deep-response range above 25% and 30%. That is the core of the efficacy argument.
Mechanism: two receptors plus amylin vs three receptors
The mechanistic difference explains the efficacy gap.
- CagriSema attacks appetite from two angles, GLP-1 and amylin, both of which curb intake and slow gastric emptying. It is a powerful appetite-suppression strategy.
- Retatrutide adds glucagon receptor activation on top of GIP and GLP-1. Glucagon signaling raises energy expenditure and pushes hepatic fat metabolism, so retatrutide leans on burning energy as well as eating less.
That third lever is the leading theory for why retatrutide reaches higher peak weight loss. It may also explain the increases in heart rate seen in trials, which is one thing the long-term safety data will need to clarify. See our overview of retatrutide side effects for the current adverse-event picture.
Side effects and tolerability
Both drugs share the gastrointestinal profile that defines this entire class. Side effects are mostly mild to moderate and cluster during dose escalation.
CagriSema in REDEFINE 1:
- Gastrointestinal events in 79.6% versus 39.9% for placebo
- Nausea 55%, constipation 30.7%, vomiting 26.1%
- Discontinuation due to adverse events: 6.0% versus 3.7% for placebo
Retatrutide in TRIUMPH-1 (12 mg):
- Nausea 42.4%, diarrhea 32.0%, vomiting 25.3%
- Discontinuation due to adverse events: 11.3% versus 4.9% for placebo
Retatrutide's higher discontinuation rate at the top dose is worth noting, and it is partly why dosing flexibility matters. Many people may settle at 8 mg or 9 mg rather than push to 12 mg. For practical context, our retatrutide dosage chart lays out the standard steps.
Approval status and timeline
This is where CagriSema currently leads. Novo Nordisk has filed CagriSema with the FDA, so it is in the regulatory queue, though it is not approved for weight loss as of mid-2026.
Retatrutide is still investigational. Its phase 3 TRIUMPH program is reporting through 2026, with additional trials covering type 2 diabetes, cardiovascular disease, sleep apnea, and liver disease still to read out. Most analysts expect an FDA submission late in 2026 or in 2027, which puts a potential approval no earlier than 2027. We track this in when will retatrutide be available. Until then, retatrutide is not an FDA-approved medication, and any product sold as such outside a trial is unregulated.
| Factor | CagriSema | Retatrutide |
|---|---|---|
| Regulatory stage | Filed with FDA | Phase 3 ongoing |
| FDA approved | No | No |
| Earliest realistic availability | 2026 to 2027 | 2027 or later |
So which one wins?
If the question is pure weight-loss efficacy, the data points to retatrutide. Its triple-agonist mechanism delivers higher mean reduction and a larger share of patients past the 25% and 30% marks.
If the question is what you can realistically get from a clinician through a regulated pharmacy sooner, CagriSema is ahead because it is already in front of the FDA. Retatrutide is at least a year or more behind on that front.
For most people the honest answer is that both are stronger than today's approved options, and the choice will come down to timing, tolerability at the doses each person can sustain, and eventually price and insurance coverage. If you are weighing retatrutide against drugs already on the market, our comparisons of retatrutide vs tirzepatide and retatrutide vs semaglutide are the more actionable reads right now.
FAQ
Is retatrutide better than CagriSema?
On peak weight loss, the trial numbers favor retatrutide (28.3% in TRIUMPH-1 versus 22.7% for CagriSema in REDEFINE 1). There has been no head-to-head trial, so the comparison is indirect, and CagriSema is closer to market.
Are CagriSema and retatrutide the same type of drug?
No. CagriSema is a combination of two peptides, the GLP-1 drug semaglutide plus the amylin analog cagrilintide. Retatrutide is a single triple agonist that activates GIP, GLP-1, and glucagon receptors.
Can I buy retatrutide right now?
Not as an approved medicine. Retatrutide is investigational and has no FDA approval anywhere in 2026. Products marketed online are not regulated approved drugs, which is covered in our notes on retatrutide without prescription.
Why was CagriSema seen as a disappointment if it caused over 20% weight loss?
Novo Nordisk had signaled an expectation near 25%. The 22.7% on-treatment result was strong in absolute terms but below that internal target, which is why the market reaction was negative despite genuinely good efficacy.
Which has worse side effects?
Both cause mostly gastrointestinal side effects during dose escalation. In trials, retatrutide's 12 mg dose had a higher discontinuation rate (11.3%) than CagriSema (6.0%), though direct comparison is limited by different trial designs.
This article is for informational purposes only and is not medical advice. Talk to a qualified clinician before starting, stopping, or changing any medication.
