CagriSema vs Tirzepatide vs Retatrutide: Head-to-Head Evidence (2026)

Last updated: June 2026

Medical disclaimer: This article is for informational purposes only and is not medical advice. CagriSema and retatrutide are investigational and not FDA-approved as of 2026; comparisons across separate trials have limits. Do not start, stop, or change treatment based on this. Consult your doctor.

Three drugs dominate the next wave of obesity care. One is approved and on pharmacy shelves. Two are still in trials. This review pulls the real numbers from the published trials and is honest about why you can't just stack the percentages side by side.

The short version: the headline figures cluster between 22% and 28%. That's a big jump over the older single-hormone drugs. But the gaps between these three are small enough that trial design, not the molecule, can explain a lot of the difference.

We'll walk through mechanism, weight loss, diabetes, safety, and approval status. Each section opens with a one-line answer in bold so you can skim. And we'll keep flagging the cross-trial problem, because it's the single most important thing to understand here.

How do the three drugs differ in mechanism?

Each drug hits a different set of gut and brain hormone receptors, and that's the core reason their results differ. Tirzepatide pulls two levers, CagriSema pulls a different two, and retatrutide pulls three.

Tirzepatide activates GIP and GLP-1 receptors. CagriSema pairs an amylin analog (cagrilintide) with a GLP-1 drug (semaglutide). Retatrutide adds a glucagon receptor on top of GIP and GLP-1, which appears to crank up energy burn.

The glucagon arm is the wild card. It may explain why retatrutide posted the highest raw weight-loss figure, though it also raises questions about heart rate and other effects that bigger trials are still sorting out.

Here's why the receptor mix matters in plain terms. GLP-1 curbs appetite and slows the stomach. GIP seems to make the GLP-1 effect smoother and may help with how the body handles fat. Amylin, the part unique to CagriSema, also tamps down hunger and signals fullness through a different pathway.

Glucagon is the odd one out. On its own, glucagon raises blood sugar, which sounds backwards for a diabetes-adjacent drug. But paired with GLP-1 and GIP, it appears to boost how many calories the body burns at rest, without spiking sugar. That's the bet behind retatrutide.

So CagriSema and tirzepatide are both two-hormone drugs, just different pairs. Retatrutide is the only triple. More levers don't automatically mean better results, but in the trials so far, the triple agonist has produced the largest numbers.

Drug	Targets	Components	Route
CagriSema	Amylin + GLP-1	Cagrilintide + semaglutide	Weekly injection
Tirzepatide	GIP + GLP-1	Single molecule	Weekly injection
Retatrutide	GIP + GLP-1 + glucagon	Single molecule (LY3437943)	Weekly injection

For a deeper dive on the triple agonist, see our retatrutide evidence review. You can also compare the two-hormone leaders in our semaglutide vs tirzepatide head-to-head.

Which produced the most weight loss in trials?

On raw numbers, retatrutide's Phase 2 result (24.2%) edged out CagriSema (22.7%) and tirzepatide (22.5%), but these come from separate trials with different patients. Read the table as three snapshots, not a race with one finish line.

In the REDEFINE 1 Phase 3 trial, CagriSema produced a 22.7% mean weight reduction at 68 weeks in 3,417 adults with obesity but no diabetes (New England Journal of Medicine, 2025). Roughly 40.4% of treatment-adherent patients lost 20% or more of their body weight (Novo Nordisk, 2024).

Tirzepatide's SURMOUNT-1 trial showed average reductions of 16.0%, 21.4%, and 22.5% at the 5 mg, 10 mg, and 15 mg doses over 72 weeks (NEJM, 2022). The top dose moved about 57% of patients past the 20% mark.

Retatrutide's Phase 2 trial reported a 24.2% least-squares mean reduction at its 12 mg dose over 48 weeks (NEJM, 2023). Lilly's later Phase 3 TRIUMPH-1 topline, announced May 2026, pushed the 12 mg figure to 28.3% at 80 weeks (Eli Lilly, 2026).

Drug	Trial	Top dose	Duration	Mean weight loss	% losing ≥20%
CagriSema	REDEFINE 1	2.4 / 2.4 mg	68 wks	22.7%	~40% (adherent)
Tirzepatide	SURMOUNT-1	15 mg	72 wks	22.5%	~57%
Retatrutide	Phase 2 (NEJMoa2301972)	12 mg	48 wks	24.2%	not reported at 48 wks
Retatrutide	TRIUMPH-1 (topline)	12 mg	80 wks	28.3%	~60% (≥25-30% range)

Note the durations don't match: 48, 68, 72, and 80 weeks. Longer trials tend to show bigger numbers because weight loss keeps building. That alone can shift a ranking.

There's a twist in the CagriSema data worth spelling out. The 22.7% figure landed below the roughly 25% that Novo Nordisk had guided investors toward, and the stock took a hit when the topline came out in late 2024 (Novo Nordisk, 2024). The miss wasn't a safety problem. It was partly a design choice.

In REDEFINE 1, patients were allowed to dial the dose down for tolerability, and many never reached the full 2.4 mg / 2.4 mg target. Among the patients who actually stuck with the top dose, weight loss ran higher. That titration flexibility is good for real-world tolerability but it pulls the trial average down.

Tirzepatide's numbers, by contrast, have held up across multiple trials. SURMOUNT-1, SURMOUNT-3, and SURMOUNT-4 all landed in a consistent range, which is reassuring even if the single-trial peak isn't the highest here (NEJM, 2022).

Retatrutide's story is the steepest curve. Its Phase 2 weight-loss line hadn't flattened by week 48, which is unusual; most drugs plateau. The TRIUMPH-1 jump to 28.3% at 80 weeks suggests that curve kept climbing with more time (Eli Lilly, 2026).

How do they compare for type 2 diabetes / A1C?

All three lower blood sugar, but tirzepatide is the only one with diabetes data the FDA has already reviewed. CagriSema and retatrutide have diabetes trial results, yet neither is approved for any use.

CagriSema's REDEFINE 2 trial in people with type 2 diabetes showed a 15.7% weight reduction over 68 weeks (Novo Nordisk press release, 2024). A separate Novo trial program reported an HbA1c drop of 1.91 percentage points in adults with type 2 diabetes (Novo Nordisk, 2026).

Tirzepatide is approved as Mounjaro for type 2 diabetes. Its SURPASS program showed A1C reductions over 2 percentage points at higher doses, with strong weight loss layered on top. Because it's been on the market for diabetes since 2022, there's far more real-world data behind it than behind the two investigational drugs.

Retatrutide's Phase 2 diabetes data showed A1C falling into the normal range for many patients at higher doses, with weight loss running 16-17% in the diabetes cohort (NEJM, 2023). It remains investigational for every indication.

Drug	Diabetes trial	A1C reduction	Weight loss in T2D	Approved for T2D?
CagriSema	REDEFINE 2	~1.8-1.9 pts	15.7%	No
Tirzepatide	SURPASS program	>2.0 pts (high dose)	up to ~12-13%	Yes (Mounjaro)
Retatrutide	Phase 2 (T2D)	up to ~2.0 pts	16-17%	No

People with type 2 diabetes usually lose less weight than people without it, across every drug in this class. That gap shows up in all three programs and is worth remembering when you compare obesity figures to diabetes figures.

Why the gap exists isn't fully settled. Part of it is biology: insulin and blood-sugar control interact with weight regulation in ways that can blunt fat loss. Part of it is the medications people with diabetes already take, some of which nudge weight up.

The practical point: don't read a 22% obesity-trial number and expect the same if you have diabetes. A 14% to 16% result in the diabetes setting is still excellent, and it usually comes with the A1C drop your doctor cares about most. For diabetes, the blood-sugar number can matter as much as the scale.

How does safety and tolerability compare?

Gut side effects dominate all three, and they look broadly similar: nausea, vomiting, diarrhea, and constipation, mostly mild to moderate. The differences are in the details, especially retatrutide's heart-rate signal.

CagriSema's most common adverse events in REDEFINE 1 were gastrointestinal, mostly mild and transient (NEJM, 2025). Tirzepatide's SURMOUNT-1 showed the same pattern, with nausea and diarrhea leading the list (NEJM, 2022).

Retatrutide's Phase 2 trial reported dose-related gut effects, partly eased by starting at a lower dose (NEJM, 2023). It also showed a small, dose-dependent rise in heart rate, a signal tied to its glucagon arm that larger trials are watching closely.

Adverse event	CagriSema	Tirzepatide	Retatrutide
Nausea	Common	Common	Common
Vomiting	Common	Common	Common
Diarrhea	Common	Common	Common
Constipation	Common	Common	Common
Heart-rate rise	Not flagged	Minimal	Dose-dependent signal
Severity	Mostly mild-moderate	Mostly mild-moderate	Mostly mild-moderate

One more wrinkle on CagriSema. In REDEFINE 1, many patients never reached the top dose, and a notable share dialed the dose down for tolerability. That titration flexibility likely held the average result below Novo's 25% target.

Retatrutide's heart-rate signal deserves a closer look since it's the one safety difference that stands out. In the Phase 2 trial, heart rate rose in a dose-dependent way, peaking around the middle of the study before easing somewhat (NEJM, 2023). A modest heart-rate bump shows up with GLP-1 drugs generally, but the glucagon component appears to add to it.

What this means for patients isn't clear yet. The Phase 3 TRIUMPH program is designed to track cardiovascular safety over a longer window, and those results will shape whether the heart-rate signal is a minor footnote or a real limit. Until then, it's a question mark, not a verdict.

For all three, the side effects tend to fade as the body adjusts, and slow dose titration is the standard way to manage them. Most people who stop these drugs do so in the first few months, during the ramp-up, not later on.

Why can't we directly compare these numbers?

There is no trial that puts CagriSema, tirzepatide, and retatrutide against each other, so every comparison here is cross-trial and carries real limits. Treat the percentages as ballpark, not bracket-style rankings.

Start with the patients. Each trial enrolled different people, with different starting weights, different comorbidity mixes, and different countries. A heavier or lighter baseline group can shift the headline percentage on its own.

Then the durations. Retatrutide's 28.3% came at 80 weeks; CagriSema's 22.7% came at 68. Weight loss in this class keeps climbing for a year or more, so a longer trial gets a head start that has nothing to do with the molecule.

The estimands matter too. Trials report results different ways: an "efficacy estimand" (what you'd lose if you stayed on the drug perfectly) usually beats a "treatment-policy estimand" (what the whole group lost, dropouts included). Mixing the two inflates or deflates a comparison without anyone lying.

The only clean head-to-head we have is tirzepatide vs semaglutide. In SURMOUNT-5, tirzepatide beat semaglutide 20.2% to 13.7% over 72 weeks (NEJM, 2025). We simply don't have that kind of direct match-up for the three drugs here.

That SURMOUNT-5 result is a useful lesson. Before it ran, you could line up SURMOUNT-1 and the semaglutide trials and guess tirzepatide was ahead. The direct trial confirmed it, but the size of the gap surprised some researchers. Cross-trial math got the direction right and the magnitude wrong.

Apply that to our three drugs. CagriSema and tirzepatide sit within a tenth of a percent of each other on raw numbers. A real head-to-head could show them tied, or it could open a gap neither set of separate trials predicted. We just don't know.

There's also the question of who dropped out and why. A trial where more people quit early can look better or worse depending on how the statisticians handle the missing data. Two trials that report results "the same way" on the surface may still treat dropouts differently underneath.

The honest takeaway is restraint. The numbers in this article are the best public evidence available in mid-2026, and they're genuinely impressive. But anyone who tells you with confidence that one of these three is definitively the strongest is reaching past what the data can support.

Which is approved and which is still in trials?

Tirzepatide is the only one you can fill at a pharmacy today; CagriSema and retatrutide are both investigational as of June 2026. That single fact outweighs any percentage difference for most patients right now.

Novo Nordisk submitted its CagriSema application to the FDA in December 2025, based on REDEFINE 1 and REDEFINE 2 (PR Newswire, 2025). A decision is expected in the second half of 2026.

Retatrutide is further back. Lilly guided to an NDA filing in late 2026 or early 2027 after the TRIUMPH-1 readout (Eli Lilly, 2026).

Drug	FDA status (June 2026)	Brand name	Approved uses	NCT (key trial)
CagriSema	NDA under review	None yet	None	NCT05567796 (REDEFINE 1)
Tirzepatide	Approved	Mounjaro, Zepbound	T2D, obesity	NCT04184622 (SURMOUNT-1)
Retatrutide	Investigational	None	None	NCT05882045 (TRIUMPH-1)

A note on what "investigational" really means for you. It's not a quality grade. CagriSema and retatrutide have both cleared large, well-run trials. The label just means the FDA hasn't finished its review, so a doctor can't write you a prescription and insurance won't cover it.

People sometimes ask about compounded or research-chemical versions of these drugs. That's a different and riskier world, with no guarantee of what's in the vial. This article is about the actual trial evidence, not gray-market sourcing, and the safe path runs through approved products and a real clinician.

If you want a wider view of what's coming, our next-gen GLP-1 pipeline guide maps the full field. The full slate of approved options lives on our medications page.

What the evidence does and does not support about picking a winner

The evidence supports one clear statement: retatrutide posted the highest raw weight-loss number, but it does not support calling any drug the definitive winner. Approval status, your health profile, and trial design all swing the answer.

What the data does support: all three drive double-digit weight loss far beyond older options. All three lower blood sugar. All three share a gut-side-effect profile that's manageable for most people who titrate slowly.

What it does not support: a confident ranking. The numbers come from different trials, different patients, and different durations, so a 1.7-point gap between CagriSema and retatrutide could vanish in a fair head-to-head.

The practical bottom line for 2026 is simple. Tirzepatide is the one your doctor can actually prescribe. The other two are promising and worth watching, but they're not options at the pharmacy counter yet. Talk to your clinician about what fits your health, your insurance, and your goals.

A few things to keep in mind as the field moves. CagriSema could be approved within months, which would give it a real-world track record fast. Retatrutide is the most powerful on paper but also the furthest from your pharmacy, with the most open safety questions.

Cost and coverage will shape choices as much as efficacy. The approved options already strain budgets and insurance plans. Two more branded injections won't change that overnight, and access may matter more than a couple of percentage points of weight loss for most people.

If you're weighing options today, the conversation worth having with your clinician isn't "which is strongest." It's "which one can I actually get, afford, and tolerate." That's where the real-world answer lives, and it's different for everyone.

Frequently Asked Questions

Is CagriSema better than tirzepatide for weight loss?

On paper CagriSema's 22.7% and tirzepatide's 22.5% are nearly identical, but they come from separate trials with different patients and durations. There's no direct head-to-head, so the data doesn't crown a winner. Tirzepatide is the only one approved today.

Which drug causes the most weight loss?

Retatrutide posted the highest figure: 24.2% in Phase 2 and 28.3% in the TRIUMPH-1 topline at 80 weeks. But its trials ran longer and enrolled different people, so the raw lead may shrink in a fair comparison. It's also still investigational.

Are CagriSema and retatrutide FDA-approved?

No. As of June 2026, neither is approved for any use. CagriSema is under FDA review with a decision expected later in 2026, and retatrutide is awaiting an NDA filing expected in late 2026 or early 2027.

Why is retatrutide stronger than the other two?

It hits three hormone receptors instead of two, adding a glucagon target that appears to raise energy expenditure. That third lever likely explains the higher weight-loss numbers, though it also brings a dose-related rise in heart rate that larger trials are studying.

Can I just compare the weight-loss percentages directly?

Not reliably. The trials differ in patient mix, duration (48 to 80 weeks), and how they report results. A longer trial or a different estimand can shift the ranking on its own. Use the numbers as rough guides, not a scoreboard.

Related Reading

• Retatrutide: complete evidence review
• Next-gen GLP-1 pipeline 2026
• Orforglipron: complete evidence review

-- The GLP-1 Daily Team