This is one of the few comparisons in the obesity-drug world that is a real head-to-head, not a cross-trial guess. In the REDEFINE 4 study, Novo Nordisk’s CagriSema went straight up against Eli Lilly’s tirzepatide — and lost. CagriSema produced 23.0% weight loss versus 25.5% for tirzepatide at 84 weeks, and failed to prove it was even as good as its rival.
Tirzepatide (sold as Zepbound and Mounjaro) is the approved benchmark everyone is chasing. CagriSema is still waiting on the FDA. Here is what the matchup actually showed and what it means.
The quick answer
Tirzepatide beat CagriSema in the only trial that pitted them directly against each other. That is the headline, and it is unusually clean because most “X vs Y” drug comparisons rely on numbers from separate studies. Here, both drugs were tested in the same trial, in the same patients, over the same 84 weeks.
CagriSema still produced substantial weight loss — 23% is a big result by any standard. It just could not out-perform, or even statistically match, the drug that already sits on pharmacy shelves. For the other CagriSema matchup, see CagriSema vs retatrutide.
CagriSema was pitched as a tirzepatide-beater. In the one trial that tested that claim head-on, it came up short.REDEFINE 4, in a sentence
What each one is
CagriSema (Novo Nordisk) is a once-weekly fixed combination of two molecules: the amylin analogue cagrilintide and the GLP-1 drug semaglutide (the active ingredient in Ozempic and Wegovy). The idea is that amylin and GLP-1 suppress appetite through different pathways, adding up to more weight loss than semaglutide alone.
Tirzepatide (Eli Lilly, sold as Zepbound for weight loss and Mounjaro for diabetes) is a single molecule that activates two incretin receptors: GIP and GLP-1. It is already approved and widely used, and it set the current benchmark for weight-loss drugs. For the research-compound angle, see tirzepatide research in Canada.
So the matchup is amylin + GLP-1 (CagriSema) versus GIP + GLP-1 (tirzepatide) — two different second ingredients bolted onto the same GLP-1 base.
REDEFINE 4: the head-to-head
REDEFINE 4, reported February 23, 2026, is the trial that defines this comparison. It enrolled 809 participants and ran for 84 weeks, directly comparing CagriSema against tirzepatide 15 mg (the top dose).
| REDEFINE 4 (84 weeks, n=809) | Result |
|---|---|
| CagriSema weight loss | 23.0% |
| Tirzepatide 15 mg weight loss | 25.5% |
| Primary endpoint | Non-inferiority — not met |
“Non-inferiority” is the key phrase. The trial was designed to show CagriSema was at least as good as tirzepatide. It could not prove that statistically — tirzepatide came out ahead on the numbers and CagriSema missed the bar. That is different from a drug flopping: 23% weight loss is excellent. It simply was not enough to dethrone the leader.
Losing a non-inferiority trial does not mean a drug is weak. It means it could not prove it was as strong as the one already winning.What “failed non-inferiority” really means
Why it matters that CagriSema lost
Tirzepatide is the benchmark for a reason. In a separate head-to-head against semaglutide (the SURMOUNT-5 trial, published in 2025), tirzepatide delivered about 20.2% weight loss versus 13.7% for semaglutide over 72 weeks. It beat the previous champion decisively. So when CagriSema — which contains semaglutide — also came up short against tirzepatide, it confirmed tirzepatide’s position at the top.
For Novo Nordisk, REDEFINE 4 was a disappointment because CagriSema was positioned as the drug that would finally edge out Lilly. Novo still filed CagriSema with the FDA in December 2025 (on the strength of its earlier REDEFINE 1 and 2 data), with a decision expected by late 2026. It will likely reach the market — just not as the new king. We cover the semaglutide comparison in retatrutide vs tirzepatide vs semaglutide.
Side effects
Both drugs are GLP-1-based, so they share the familiar gastrointestinal side effects: nausea, vomiting, diarrhea and constipation, usually worst when starting or increasing the dose and easing over time. Tirzepatide’s profile is well characterised from years of real-world use; CagriSema’s adds the amylin component, but gastrointestinal complaints still lead.
Because tirzepatide is approved and widely prescribed, there is far more real-world safety data on it than on CagriSema, which is still pre-approval. Anyone weighing an approved GLP-1 drug should discuss the trade-offs with a doctor or pharmacist; none of this is medical advice.
What you can actually get
This is where the two part ways completely. Tirzepatide is approved (as Zepbound and Mounjaro) and available by prescription in many markets. CagriSema is not approved anywhere as of October 2026 and is awaiting an FDA decision.
In Canada, the usual caution applies: approved products are accessed through a clinician, while unauthorized injectable peptides sold online are illegal, and Health Canada’s 2026 advisory was explicit that a “research use only” label gives no exemption. Research-grade tirzepatide sold for laboratory use is a separate category that is not for human use. See tirzepatide research in Canada.
Myths
“Myth: CagriSema is a failed drug.”
It produced 23% weight loss and will likely be approved. It failed one specific goal — beating tirzepatide in REDEFINE 4 — not the broader test of whether it works.
“Myth: Tirzepatide and CagriSema are basically the same.”
They share a GLP-1 base but differ in the second ingredient: tirzepatide adds GIP (one molecule, two receptors), CagriSema adds amylin (two molecules combined). Different mechanisms, different companies.
“Myth: The 2.5-point gap is huge.”
23.0% vs 25.5% is a real but modest difference. The bigger story is statistical: CagriSema was supposed to prove non-inferiority and could not, which matters more for its positioning than the raw gap suggests.
“Myth: You can buy CagriSema now because semaglutide is available.”
CagriSema is a specific approved-pending combination product; it is not the same as buying semaglutide. It is not authorized or sold anywhere yet.
For researchers
For laboratory pharmacology work on incretin and amylin biology, TrueLabs supplies reference peptides in CAD, for in vitro and laboratory research only, never for human or veterinary use, including TZ-2 (tirzepatide) from $73, cagrilintide from $40 and RT3 (retatrutide) from $90. For a combination like CagriSema, a certificate of analysis should confirm each component — see how to read a peptide COA and the COA library.
FAQ
Tap a question to reveal the answer.
Is CagriSema or tirzepatide better for weight loss?
In the REDEFINE 4 head-to-head, tirzepatide won: 25.5% weight loss versus 23.0% for CagriSema at 84 weeks, and CagriSema failed to meet non-inferiority. Both are strong, but tirzepatide came out ahead in the only direct comparison.
What was REDEFINE 4?
REDEFINE 4 was a phase 3 trial (reported February 2026, 809 participants, 84 weeks) that directly compared CagriSema against tirzepatide 15 mg. CagriSema produced 23.0% weight loss versus tirzepatide’s 25.5% and did not meet its non-inferiority goal.
Does “failed non-inferiority” mean CagriSema doesn’t work?
No. CagriSema produced about 23% weight loss, a large effect. It failed to statistically prove it was at least as good as tirzepatide, which is a positioning setback, not evidence that the drug is ineffective.
What is the difference between CagriSema and tirzepatide?
CagriSema (Novo Nordisk) combines the amylin analogue cagrilintide with semaglutide. Tirzepatide (Eli Lilly, sold as Zepbound/Mounjaro) is one molecule hitting GIP and GLP-1. Different second ingredient, different maker.
Is CagriSema approved?
Not yet. Novo Nordisk filed with the FDA in December 2025 and a decision is expected by late 2026. It is not approved or sold in Canada as of October 2026.
Is tirzepatide available in Canada?
Tirzepatide is an approved medicine (Zepbound/Mounjaro) accessed through a clinician where authorized. Research-grade tirzepatide sold for laboratory use is a separate category that is not for human use, and unauthorized injectable peptides bought online are illegal in Canada.
Why did Novo Nordisk still file CagriSema after it lost?
Because REDEFINE 4 was one trial with one goal (beating tirzepatide). CagriSema’s broader programme (REDEFINE 1 and 2) supported its efficacy, so Novo filed on that basis. It will likely reach the market, just not as the category leader.
How does tirzepatide compare to semaglutide?
In the SURMOUNT-5 head-to-head (published 2025), tirzepatide produced about 20.2% weight loss versus 13.7% for semaglutide over 72 weeks, beating it clearly. That is part of why tirzepatide is the current benchmark.
Related reading
- CagriSema vs retatrutide
- Retatrutide vs tirzepatide vs semaglutide
- Tirzepatide research in Canada
- What is survodutide?
- The next weight-loss drugs after Ozempic
References
- CagriSema did not meet primary endpoint of non-inferiority to tirzepatide (REDEFINE 4, February 23, 2026). Drug Topics. Drug Topics
- Tirzepatide bests semaglutide for weight loss: SURMOUNT-5 (20.2% vs 13.7%, 72 weeks). TCTMD. TCTMD
- Health Canada. Think twice before injecting peptides bought online (advisory, April 9, 2026). Health Canada
This article summarizes published research and regulatory information for information only and is not medical advice. TrueLabs research compounds are sold for in vitro and laboratory research use only and are not intended for human or veterinary use.