Randomised controlled trials
In the trials below, people were assigned at random to take Orforglipron or a dummy pill (placebo). All the weight loss figures are averages: how much body weight fell from the start.
| Trial | Key result | Source |
|---|---|---|
| [1]ATTAIN-1 | 12.4% mean weight loss at the highest dose studied (36 mg of the trial capsule, shown in the FDA label as the equivalent 17.2 mg tablet). 59.6% achieved ≥10% loss. Nausea 29–36% vs. 10% placebo; vomiting 13–24% vs. 4% placebo. | New England Journal of Medicine 2025 ↗ |
| [2]ATTAIN-2 | 10.5% weight loss at highest dose. HbA1c reduced by 1.8%. Consistent GI safety profile with injectable GLP-1 class. | The Lancet 2025 ↗ |
| [3]ATTAIN-MAINTAIN (transition from injectable) | Weight maintained following switch — average difference of 0.9 kg vs. those continuing injectable GLP-1. All primary endpoints met. | Eli Lilly press release 2025 ↗ |
Reported side effects
The rates below come from the ATTAIN-1 trial. View source
| Side effect | Frequency in trial |
|---|---|
| Nausea | 33% |
| Vomiting | 19% |
| Constipation | 18% |
| Diarrhoea | 15% |
Body composition data
No published body composition substudy for orforglipron. As a GLP-1 agonist, the lean mass profile is expected to be similar to injectable GLP-1 drugs — proportional to total weight lost.
Heart and metabolic data
Cardiovascular outcomes data pending. Blood pressure and lipid improvements observed across Phase 3 trials. 91% of prediabetic participants reached near-normal blood sugar vs. 42% placebo in ATTAIN-1.