Weight-Loss Medications Less Effective in the ‘Real World’: Study

Weight-loss medications like Ozempic and Mounjaro are not as effective in a “real-world” setting, according to a new study.

The study — published June 10 in the Obesity Journal — analyzed nearly 8,000 patients who were classified as having severe obesity. Between 2021 and 2023, they were treated with semaglutide or tirzepatide, injectable GLP-1 medications, in a real-world setting.

GLP-1 is short for glucagon-like peptide-1 receptor agonists, which work in the brain to impact satiety. Semaglutide is sold under brand names Ozempic and Wegovy, and tirzepatide is sold under brand names Mounjaro and Zepbound.

In a follow-up study, which ended in December 2024, researchers grouped patients who discontinued their obesity medications into those who discontinued early (within 3 months) and late (within 3-12 months).

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They found that more than 20% of patients discontinued their medications early and 32% discontinued their medications late. Additionally, more than 80% of patients were on lower maintenance dosages of their medications.

After a year of treatment, the average weight loss was 3.6% for those who discontinued their treatment early, compared to 6.8% for those who discontinued their treatment late. Those who continued treatment lost about 12% of their body weight.

During clinical trials for the GLP-1s, patients lost about 15% to 20% of their body weight.

“Our findings about the real-world use patterns of these medications and associated clinical outcomes could inform the decisions of healthcare providers and their patients on the role of treatment discontinuation and maintenance dosage in achieving clinically meaningful weight reductions,” Dr. Hamlet Gasoyan, Cleveland Clinic researcher and lead author of the study, said in a statement.

The study notes that discontinuation rates during real-world use were higher than those in a clinical trial setting due to high out-of-pocket costs, issues with insurance coverage, side effects and supply shortages.