Orforglipron phase 2: a daily GLP-1 pill for weight loss

Why this study matters

Orforglipron is an experimental medicine. It is not approved in Canada as of September 2026, and this study is research only. Most GLP-1 medicines used for weight management in Canada are injections. Orforglipron is a small-molecule GLP-1 receptor agonist taken as a daily pill, with no restrictions on food or water. This was the first mid-stage trial to test whether the pill produces meaningful weight loss and what side effects it causes. For Canadian readers following the news about oral weight-management medicines, this is where the story starts.

Who was in the study

The trial enrolled 272 adults. All of them had obesity, or had overweight plus at least one weight-related coexisting condition. None had diabetes. At the start of the trial, the average body weight was 108.7 kg and the average BMI was 37.9. BMI, or body mass index, is weight in kilograms divided by height in metres squared. The study ran for 36 weeks. The published summary we reviewed does not report the age range or the countries where the trial was run.

What the researchers did

This was a phase 2, randomized, double-blind trial. Phase 2 means a mid-stage trial designed to find the right dose and to get an early read on benefit and harm. Randomized means participants were assigned to a group by chance. Double-blind means neither the participants nor the study staff knew who was taking the medicine and who was taking placebo. A placebo is an inactive pill that looks the same as the real one.

Participants took orforglipron at one of four doses (12, 24, 36 or 45 mg) or placebo once a day for 36 weeks. The primary end point, meaning the main result the trial was designed to measure, was the percentage change in body weight at week 26. Weight change at week 36 was a secondary end point. The published summary we reviewed does not say what lifestyle support the groups received.

What they found

At week 26, the primary time point, the average change in body weight ranged from -8.6% to -12.6% across the orforglipron dose groups, compared with -2.0% in the placebo group.

At week 36, the average change ranged from -9.4% to -14.7% with orforglipron, compared with -2.3% with placebo (R32-C60).

A weight reduction of at least 10% by week 36 occurred in 46 to 75% of participants taking orforglipron, depending on the dose, compared with 9% of those taking placebo.

The abstract states that orforglipron improved all of the prespecified weight-related and cardiometabolic measures, but the summary we reviewed does not give those numbers.

The published summary reports ranges across the dose groups rather than a result for each dose. It does not report a between-group difference with a confidence interval, so we cannot give one here.

Side effects and people who stopped

The most common side effects with orforglipron were gastrointestinal: stomach and bowel symptoms. These were mild to moderate and happened mostly while the dose was being increased. Gastrointestinal events led to stopping orforglipron in 10 to 17% of participants across the dose groups. The published summary we reviewed does not report the stopping rate in the placebo group, or the overall dropout rate by group. The authors state that the safety profile was consistent with the GLP-1 receptor agonist class.

What this study does not tell you

• This is phase 2 evidence. It was designed to find doses, not to prove long-term benefit or safety. The larger phase 3 trial, ATTAIN-1, came later.
• Orforglipron is not approved in Canada as of September 2026. Nothing here describes a medicine you can be prescribed today.
• The summary reports ranges across doses, so we cannot say how much weight people lost at any single dose.
• People with diabetes were excluded, so the results do not apply to them.
• The trial lasted 36 weeks. It does not tell you what happens after a year or more, or what happens when the pill is stopped.
• Rare or long-term harms cannot be detected in a trial of 272 people.
• Do not compare these percentages with numbers from trials of other medicines. Different trials enrol different people, run for different lengths of time, and measure results in different ways.
• The trial was funded by the company that makes the medicine.

What it means in Canada

Orforglipron is not approved in Canada as of September 2026. This trial is part of the research record for a medicine that may or may not reach the Canadian market. You can follow emerging medicines on our medicines page. For medicines that are available in Canada, see semaglutide in Canada and tirzepatide in Canada, and public drug coverage by province for how they are paid for.

Related reading

Other studies in this library that bear on the same question.

Source