Research brief · 2026-09-09
How Long Do People Actually Stay on GLP-1s?
Clinical trials of semaglutide, tirzepatide and liraglutide, all prescription medications, run on fixed schedules with built-in follow-up and strong incentives to stay enrolled. Real life is different, and the best way to see the difference is to look at prescription records. Every real-world cohort that has done so lands in roughly the same place: most people do not stay on these drugs as long as the trials that established their benefits.
The baseline figure comes from a 2024 analysis by Gleason and colleagues in the Journal of Managed Care and Specialty Pharmacy. Using integrated pharmacy and medical claims, they identified 4,066 adults with obesity and no diabetes who started a GLP-1 for weight in 2021. Persistence, defined as no gap of 60 days or more, was 46.3 percent at six months and 32.3 percent at one year. Only about a quarter met a strict adherence threshold. The drug mattered a great deal: one-year persistence was 47.1 percent for semaglutide and 19.2 percent for liraglutide in the same dataset.
Cost is an obvious suspect, so a 2025 study by Samuels and colleagues in Diabetes, Obesity and Metabolism is especially telling. It followed 2,306 patients at an academic obesity clinic enrolled in a bundle that provided semaglutide or tirzepatide at no cost to the patient. Median persistence was still only 10.7 months. Those who stayed six months had lost a median of 9.4 percent and those who reached twelve months 14.4 percent, close to trial figures, but the median patient did not reach a year even with cost removed.
Structured support did not fix it either. A 2026 retrospective cohort by Talay and colleagues, in the same journal, followed 4,535 patients in a semaglutide-supported digital weight-loss service in Germany. Only 12 percent remained adherent to both the medication and the tracking protocol for a full year. That minority lost 15.1 percent on average, but the authors described the programme's population-level impact as fundamentally limited by 88 percent attrition.
What none of these studies can say is why people stop. Claims and health-record data show that a prescription was not refilled, not whether the reason was cost, side effects, a feeling of being done, a shortage, or something else. Definitions of persistence also vary between studies, so the exact percentages are not directly comparable, and most of the data predate wider low-cost access. Decisions about starting or stopping these medications belong with a physician.
Sources
- Gleason PP, et al. Real-world persistence and adherence to glucagon-like peptide-1 receptor agonists among obese commercially insured adults without diabetes
- Journal of Managed Care & Specialty Pharmacy 2024
- Samuels JM, et al. Real-world titration, persistence & weight loss of semaglutide and tirzepatide in an academic obesity clinic
- Diabetes, Obesity & Metabolism 2025
- Talay L, Hom J, Tan M, Ahuja N. Real-World Effectiveness and 12-Month Persistence of a Semaglutide-Supported Digital Weight-Loss Service: A Retrospective Cohort Study in Germany
- Diabetes, Obesity & Metabolism 2026
Peptide Proof reports what studies found. We do not give medical advice, dosing guidance, or treatment recommendations.