The short answer
Substantial weight loss occurred with and without reported nausea, vomiting or diarrhoea. Symptoms were not the main explanation.
What did researchers examine?
Domenica Rubino and colleagues revisited four SURMOUNT trials involving adults with overweight or obesity, with or without type 2 diabetes. They compared weight outcomes according to participants' reported digestive symptoms.
Themes, not a pooled outcome rate
With digestive symptoms
Weight loss reported
Without digestive symptoms
Weight loss reported
Original visual based on the study.
| Group or measure | Result |
|---|---|
| With digestive symptoms | Weight loss reported |
| Without digestive symptoms | Weight loss reported |
What did they find?
Weight reduction was broadly similar with and without these symptoms. Statistical models associated digestive symptoms with up to 3.1% of total weight reduction. That is not 3.1 percentage points of body weight, and the model does not prove causation.
What were the trade-offs?
Most digestive events occurred during dose increases. Across tirzepatide groups, 1.0–10.5% stopped treatment because of digestive adverse events; this range spans different trials and treatment groups.
What should readers take from it?
Feeling sick is not a useful scorecard for success. The analysis relied on self-reported symptoms and available endpoint weights, excluding data after treatment stopped. It may therefore better represent people who tolerated treatment. Symptoms still matter.
Sources
Rubino and colleagues, Diabetes, Obesity and Metabolism, 2025. Funded by Eli Lilly.