Eli Lilly's retatrutide beats Ozempic in head-to-head trial: what it means for Canadian GLP-1 patients

This article is for informational purposes only and is not medical advice. Consult your Canadian healthcare provider about your situation.

Retatrutide beats semaglutide in a 2026 head-to-head trial

A phase 3 trial reported by Reuters on October 28, 2026, found that retatrutide, Eli Lilly's investigational triple-hormone receptor agonist, produced statistically greater reductions in body weight and HbA1c (a standard measure of blood sugar control over roughly three months) compared with semaglutide (sold in Canada as Ozempic for type 2 diabetes and as Wegovy for weight management) in adults with type 2 diabetes. The trial is the first direct comparison between the two drugs at scale, and its results were reported by Reuters via CTV News.

For Canadians currently on semaglutide, or waiting to start a GLP-1 therapy, the practical answer right now is: nothing changes yet. Retatrutide has not received approval from Health Canada, the federal regulator responsible for authorizing drugs sold in this country. It is not available at Canadian pharmacies, and no provincial drug plan, including OHIP (Ontario Health Insurance Plan), RAMQ (Quebec's Regie de l'assurance maladie du Quebec), MSP (British Columbia's Medical Services Plan), or AHCIP (Alberta Health Care Insurance Plan), covers it. Canadians who want access would need to enroll in a clinical trial.

What this means in Canada

Retatrutide is FDA-approved (US) for neither obesity nor type 2 diabetes as of this writing; it remains under regulatory review in the United States as well. Health Canada has not issued a Notice of Compliance or any interim authorization for retatrutide. The drug is not listed in Health Canada's drug product database.

Semaglutide, by contrast, is well established in Canada. Ozempic (semaglutide 0.5 mg, 1 mg, and 2 mg injection) is Health Canada-approved for type 2 diabetes management. Wegovy (semaglutide 2.4 mg injection) is Health Canada-approved for chronic weight management in adults with obesity or overweight plus at least one weight-related condition. Provincial coverage varies: some plans cover Ozempic for diabetes with prior authorization, but Wegovy coverage for obesity alone remains inconsistent across provinces and is generally not covered without special authorization.

The Society of Obstetricians and Gynaecologists of Canada (SOGC) has not issued a position statement on retatrutide. The Canadian Diabetes Association's clinical practice guidelines address semaglutide and other approved GLP-1 receptor agonists, but retatrutide falls outside current Canadian prescribing guidance because it is not approved here.

Canadian telehealth platforms that prescribe GLP-1 therapies, including Felix, a Canadian men's and women's health platform, Cleo, a Canadian women's health platform, and Science & Humans (scienceandhumans.com), a Canadian hormone and metabolic health service, currently offer semaglutide where clinically appropriate and where supply allows. None can prescribe retatrutide to Canadian patients.

What changed

Retatrutide works differently from semaglutide. Semaglutide is a GLP-1 (glucagon-like peptide-1) receptor agonist: it mimics one gut hormone to reduce appetite and slow gastric emptying. Retatrutide is a triple agonist, targeting GLP-1, GIP (glucose-dependent insulinotropic polypeptide), and glucagon receptors simultaneously. The glucagon receptor component is the main addition over tirzepatide (sold in Canada as Mounjaro for type 2 diabetes and as Zepbound for obesity, both Health Canada-approved), which targets GLP-1 and GIP only.

The 2026 head-to-head trial compared retatrutide directly against semaglutide, and retatrutide produced larger reductions in both body weight and HbA1c. This is a meaningful result because most prior GLP-1 comparisons have been indirect, drawn from separate trials with different populations and designs. A direct randomized comparison carries more weight clinically.

The Endocrine Society has previously noted that triple agonism may produce additive metabolic effects beyond what single or dual agonists achieve, though it has not yet issued formal guidance on retatrutide specifically, as regulatory approval in any jurisdiction is still pending.

What Canadian patients should know

If you are currently taking semaglutide (Ozempic or Wegovy) and it is working for you, this trial is not a reason to stop or switch. Retatrutide is not available to you through any Canadian pharmacy or prescriber outside a research setting.

If you are not yet on a GLP-1 therapy and are interested in options, the drugs currently available in Canada include:

Semaglutide (Ozempic, Wegovy): Health Canada-approved, available by prescription, coverage varies by province and indication.
Tirzepatide (Mounjaro, Zepbound): Health Canada-approved, available by prescription, coverage also varies.
Liraglutide (Victoza for diabetes, Saxenda for weight): Health Canada-approved, longer on market, generally broader formulary coverage.

If you are interested in whether retatrutide trials are recruiting in Canada, ClinicalTrials.gov lists active Eli Lilly studies and their Canadian site participation. Your physician or endocrinologist can advise whether you meet eligibility criteria.

Provincial pharmacare differences matter here. Quebec's RAMQ covers some GLP-1 drugs for diabetes under specific criteria. Ontario's Trillium Drug Program may cover semaglutide for diabetes with documentation of medical necessity. British Columbia's PharmaCare and Alberta's provincial drug benefit program have their own criteria. For weight management without a diabetes diagnosis, out-of-pocket costs for semaglutide in Canada typically run between CAD $250 and $400 per month depending on dose and pharmacy.

Limitations and open questions

The full trial data, including the study protocol, exact cohort size, duration, and safety profile breakdown, had not been published in a peer-reviewed journal at the time of this article. The Reuters report is based on data presented or released by Eli Lilly. Independent peer review may surface findings that modify the headline result.

Side effect comparisons between retatrutide and semaglutide from this trial are not yet fully detailed in public reporting. The glucagon receptor component of retatrutide raises questions about effects on heart rate and potential for nausea at higher doses. The Mayo Clinic's overview of GLP-1 therapies notes that gastrointestinal side effects are common across this drug class and vary by agent and dose titration.

Health Canada has not issued guidance on a retatrutide review timeline. The SOGC has not commented. Whether retatrutide will be priced competitively with tirzepatide and semaglutide in Canada, if and when it reaches approval, is unknown. Lilly's pricing history with tirzepatide suggests the drug will be expensive before any provincial formulary negotiation.

The trial compared retatrutide against semaglutide, not against tirzepatide. Given that tirzepatide already outperforms semaglutide on weight outcomes in published trials, the more clinically relevant question for Canadian prescribers may be how retatrutide compares to tirzepatide. That data is not yet available.