Retatrutide Phase 3 Results 2026: What Canadians Should Know

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Btrep2025

September 30, 2026

On September 30, 2026

Retatrutide is back in the spotlight after new Phase 3 results from the TRIUMPH-2 trial were released on September 29, 2026. The study evaluated retatrutide in adults with type 2 diabetes and obesity or overweight, and the results add important new data to one of the most closely watched metabolic drug-development programs in the world.

For Canadians, the timing is especially relevant because multiple retatrutide trials are currently listed in the Canadian Clinical Trial Search Portal. At the same time, retatrutide remains investigational and has not been approved for human use by Health Canada.

What is retatrutide?

Retatrutide is an investigational once-weekly triple hormone receptor agonist being developed by Eli Lilly. It activates three metabolic hormone receptors: GIP, GLP-1, and glucagon.

That makes it mechanistically different from single- and dual-pathway agents. Retatrutide is still in clinical development, and Lilly has repeatedly stated that it is not approved for public use.

What did the new TRIUMPH-2 Phase 3 trial show?

TRIUMPH-2 was an 80-week randomized, double-blind, placebo-controlled Phase 3 trial involving adults with type 2 diabetes and obesity or overweight.

According to detailed results released by Lilly, participants receiving retatrutide 12 mg lost an average of 20.8% of body weight under the efficacy estimand. Participants receiving 9 mg lost 19.1%, while those receiving 4 mg lost 12.7%. The placebo group lost 4.0%.

Among participants with a baseline BMI of 35 or greater, those receiving 12 mg lost an average of 23.4% of body weight.

At the end of the study, 59.5% of participants receiving the 12 mg dose no longer met BMI criteria for obesity.

What happened to A1C?

The trial also showed substantial improvements in glycemic control.

Retatrutide 4 mg reduced A1C by an average of 1.4 percentage points.
Retatrutide 9 mg reduced A1C by 1.6 percentage points.
Retatrutide 12 mg reduced A1C by 1.5 percentage points.
Placebo reduced A1C by 0.2 percentage points.

Up to 40.0% of participants in the retatrutide groups reached an A1C below 5.7%.

What other cardiometabolic changes were reported?

At the highest dose, Lilly reported average reductions in several additional risk markers, including triglycerides, non-HDL cholesterol, systolic blood pressure, waist circumference, and high-sensitivity C-reactive protein.

These findings are relevant because obesity and type 2 diabetes frequently occur alongside broader cardiovascular and metabolic risk.

What side effects were seen?

The most common adverse events were gastrointestinal, including diarrhea, nausea, constipation, reduced appetite, and vomiting. These effects were generally reported as mild to moderate and often resolved during treatment.

Discontinuation because of adverse events occurred in 3.8% of participants on 4 mg, 11.6% on 9 mg, and 7.7% on 12 mg, compared with 4.9% on placebo.

Is retatrutide approved in Canada?

No. Retatrutide remains investigational. Lilly Canada stated in August 2026 that retatrutide has not been approved for human use by Health Canada or any other regulatory agency.

That distinction matters because public interest in retatrutide has grown much faster than its regulatory status.

What retatrutide trials are happening in Canada?

Canada is participating in multiple parts of the retatrutide development program.

The Canadian Clinical Trial Search Portal currently lists studies involving:

weight-loss maintenance in obesity (TRIUMPH-6)
obesity and established cardiovascular disease (TRIUMPH-3)
dose-escalation strategies in obesity or overweight (TRIUMPH-9)
obesity or overweight with chronic low-back pain (TRIUMPH-7)
obesity or overweight with knee osteoarthritis (TRIUMPH-4)
cardiovascular and kidney outcomes (TRIUMPH-Outcomes)
a head-to-head Phase 3 study comparing retatrutide with semaglutide in type 2 diabetes (TRANSCEND-T2D-2)

This broad trial program suggests researchers are looking beyond weight loss alone and evaluating effects across diabetes, cardiovascular disease, kidney disease, pain-related conditions, and weight maintenance.

Why is the semaglutide comparison trial important?

One of the most interesting Canadian-listed studies is TRANSCEND-T2D-2, a Phase 3 trial comparing once-weekly retatrutide with once-weekly semaglutide in adults with type 2 diabetes whose blood sugar is not adequately controlled with metformin, with or without an SGLT2 inhibitor.

That study is important because direct head-to-head trials are much more informative than comparing percentages from separate studies conducted in different populations.

What should Canadians take away from the new data?

The main takeaway is that retatrutide now has substantial Phase 3 evidence in adults with type 2 diabetes and obesity or overweight, including meaningful changes in body weight and A1C.

But the development program is still ongoing.

Retatrutide is not yet approved in Canada, and the results should be understood as clinical-trial evidence for an investigational drug rather than evidence of an approved treatment available to the public.

Frequently asked questions

Is retatrutide available in Canada?

No. Retatrutide is investigational and has not been approved for human use by Health Canada.

How much weight loss was reported in TRIUMPH-2?

Under the efficacy estimand, the 12 mg retatrutide group lost an average of 20.8% of body weight over 80 weeks.

Did retatrutide lower A1C?

Yes. Average A1C reductions were up to 1.6 percentage points in TRIUMPH-2.

Is retatrutide being studied in Canada?

Yes. Multiple retatrutide studies are listed in the Canadian Clinical Trial Search Portal, including obesity, cardiovascular, kidney, pain, and diabetes studies.

Has retatrutide been compared directly with semaglutide?

A Phase 3 head-to-head trial comparing retatrutide with semaglutide in adults with type 2 diabetes is listed in the Canadian Clinical Trial Search Portal. Results from that trial should be interpreted when they become available rather than inferred from unrelated studies.

Sources

This article is for educational purposes and summarizes publicly available clinical-trial information. It is not medical advice.

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