GLP-1 receptor agonists can slow gastric emptying and affect satiety pathways. Food may stay in the stomach longer, and fullness signals can become more noticeable. Large portions, high-fat meals, or eating quickly may make nausea more likely for some people, which is why GI-management guidance often focuses on meal size, fat content, and pace.

In Wegovy injection 2.4 mg adult weight-reduction trials, nausea was reported in 44% of semaglutide-treated adults versus 16% on placebo. In the pooled STEP 1-3 semaglutide 2.4 mg tolerability analysis, nausea was 43.9% versus 16.1%, the median nausea duration was 8 days, and first gastrointestinal adverse events plateaued after week 20. The Zepbound label reports nausea in 8% on placebo, 25% on 5 mg, 29% on 10 mg, and 28% on 15 mg, with most nausea, vomiting, and diarrhea events occurring during dose escalation and decreasing over time.