Tirzepatide activates GIP and GLP-1 receptors, which participate in glucose regulation and appetite signalling. In SURMOUNT-1, adults with obesity or overweight and a related complication, without diabetes, lost substantially more weight than those receiving placebo. The highest study group averaged 20.9% weight loss at 72 weeks, versus 3.1% with placebo. Participants also received lifestyle support.

Two randomized trials studied tirzepatide in adults with obesity and moderate-to-severe obstructive sleep apnea. Over 52 weeks, it reduced breathing interruptions, body weight and several sleep-related symptom measures compared with placebo. These results concern a defined condition and clinical preparation. They do not show that a research vial treats snoring or that prescribed airway-pressure treatment can be stopped.

SURMOUNT-5 directly compared tirzepatide with semaglutide in adults with obesity without diabetes. At 72 weeks, estimated average weight loss was 20.2% with tirzepatide and 13.7% with semaglutide. This open-label trial provides a more useful comparison than unrelated study headlines. It does not establish superiority over retatrutide, which was not part of that comparison.

Digestive effects, including nausea, diarrhea and vomiting, were commonly reported in clinical trials, and some participants stopped treatment. Results apply to monitored clinical preparations. A laboratory certificate can help assess identity, purity or content when those tests are included, but cannot by itself establish sterility, clinical safety or equivalence to the medicine used in a trial.