In clinical trials, semaglutide and tirzepatide completion rates exceed 80%. In the real world, 50-70% of patients discontinue within 12 months. The gap between trial persistence and real-world persistence is the central challenge of GLP-1 medicine — and the data tells us exactly why.
The persistence data landscape
| Study / Source | Drug | N | 12-mo Persistence | Key Finding |
|---|---|---|---|---|
| Gasoyan et al. (Obesity, 2024) | Semaglutide (all) | ~42,000 | 32-46% | Cost was primary discontinuation driver |
| Wharton et al. (DOM, 2025) | Semaglutide 2.4mg | ~8,200 | ~42% | GI intolerance caused 18% of stops |
| IQVIA Tracker (2024-2026) | All GLP-1 AOMs | Market-level | 30-50% | Injectable persistence > oral |
| Trujillo et al. (JMCP, 2025) | Systematic review | Meta | 35-55% | Insurance coverage strongest predictor |
Why patients stop
Cost (primary driver — 35-45% of discontinuations). At $800-1,300/month for brand-name GLP-1s, affordability is the single largest predictor of persistence. Patients whose insurance covers the medication persist at approximately 2x the rate of cash-pay patients. Manufacturer savings programs and compounded alternatives improve cost-related persistence, but the data on compounded medication persistence specifically is limited.
Side effects (20-25% of discontinuations). GI intolerance — persistent nausea, vomiting, or diarrhea that doesn't resolve during titration — accounts for most side-effect-related discontinuation. The majority of GI side effects resolve within 4-8 weeks of reaching maintenance dose, but patients who discontinue during the titration phase before GI adaptation occurs represent a significant proportion of the attrition.
Formulary and access changes (10-15%). Insurance plans change formularies, copay amounts increase at renewal, prior authorization requirements change, or patients change jobs and insurance plans. These administrative disruptions cause treatment gaps that frequently become permanent discontinuation.
Achieving treatment goals (5-10%). Some patients stop because they've reached their weight goal and choose to attempt weight maintenance without medication. The weight regain data suggests this strategy succeeds in a minority of cases — most patients regain 50-70% of lost weight within 12 months of stopping.
Patient choice / lifestyle factors (10-15%). Injection burden, daily pill timing requirements, dietary restrictions (avoid high-fat meals), and general treatment fatigue contribute to discontinuation in patients without specific cost or side effect barriers.
The persistence problem is primarily an access problem, not a medication problem. Insurance coverage is the strongest predictor of 12-month persistence. Patients with coverage persist at roughly 2x the rate of those without. Until GLP-1 medications are affordable long-term — through insurance mandates, biosimilar competition, or manufacturer pricing — discontinuation rates will remain the Achilles' heel of this drug class.
What improves persistence
Three factors consistently predict higher persistence across studies: stable insurance coverage with manageable copays, structured support programs (coaching, regular follow-ups, app-based tracking), and injectable rather than oral formulation (once-weekly injection adherence exceeds daily oral adherence by approximately 15-20 percentage points).
Providers who monitor patients regularly and proactively manage side effects during titration also see higher persistence. The patients most likely to discontinue are those who are prescribed, shipped medication, and then have no clinical contact until a problem prompts them to stop rather than seek adjustment.