The most frequently reported side effects of semaglutide involve the gastrointestinal system. Across multiple large-scale randomized controlled trials and meta-analyses, nausea, vomiting, diarrhea, and constipation consistently appear as the most common adverse events. These symptoms are usually dose-dependent, with higher doses producing more frequent and more severe GI issues.
Other less common but clinically relevant side effects include gallbladder disease (notably cholelithiasis), rare cases of pancreatitis, worsening of diabetic retinopathy in certain patients, and in isolated case reports, even sarcopenia or gastroparesis.
Importantly, a significant number of patients discontinue semaglutide early because of persistent side effects. Meta-analyses report discontinuation rates up to twice as high in semaglutide groups compared to placebo, with GI effects being the main driver.
Despite early side effects, semaglutide generally demonstrates a favorable long-term safety profile. A comprehensive meta-analysis including over 57,000 patients found no increase in serious adverse events compared to placebo, with side effects largely limited to early and transient GI disturbances. Long-term follow-up studies also suggest that with proper patient monitoring, semaglutide remains safe and effective for sustained use.
The timeline and intensity of side effects vary across patients, influenced by dosage, rate of dose escalation, pre-existing gastrointestinal conditions, and overall health status. Gradual dose titration is strongly associated with improved tolerability, as is patient education about expected symptoms and their transient nature. Supportive measures, including dietary adjustments or adjunctive therapies, may further ease GI discomfort.