Real-World GLP-1 Adherence: Why 50% of Patients Quit Within a Year

Clinical trials report GLP-1 discontinuation rates of 7–11%. Real-world claims data tells a radically different story. An IQVIA analysis of prescription claims found that among patients newly prescribed GLP-1s for obesity in 2023–2024, 90% either never started therapy or dropped off within a year. Only 30% even filled their first prescription.¹

This gap between trial retention and real-world persistence is not a footnote. It is the single most important variable determining whether GLP-1s deliver population-level health improvements or remain a pharmacological curiosity for a minority of patients who can afford and tolerate them.

The Numbers in Detail

Why Patients Quit

1. Cost

At $150–$1,400/month depending on insurance coverage and product, cost is the number one barrier. The IQVIA finding that 70% of patients never even fill their first prescription likely reflects sticker shock at the pharmacy counter. Cost is also the primary driver of the "one-and-done" phenomenon.¹

2. Side Effects

Nausea, vomiting, and diarrhea affect 30–50% of patients during dose escalation. For most, these resolve within weeks. For a meaningful minority, they don't — and the discomfort drives discontinuation. Real-world data shows higher adverse-event-driven dropout than trials, likely because trial participants receive more intensive support and coaching.³

3. Supply Disruptions

The 2023–2024 semaglutide and tirzepatide shortages forced involuntary gaps in treatment for millions of patients. Many never restarted. Supply has stabilized in 2026, but the damage to persistence rates is visible in the claims data.⁵

4. Suboptimal Dose Titration

Academic clinic data shows that many real-world patients never reach the therapeutic dose levels used in trials. Slow titration, provider caution, and patient-driven dose capping mean that a significant percentage of patients achieve lower weight loss than trials predict — which can lead to disappointment and discontinuation.³

5. Weight Plateau Frustration

Weight loss typically plateaus at 6–9 months. Patients who expect continuous linear loss may interpret a plateau as "the drug stopped working" and discontinue, when in reality the drug is maintaining a new set point that would revert without it.

What Predicts Who Stays On

Factors associated with higher persistence across multiple studies:

• Weekly dosing (vs. daily) — Wegovy and Ozempic have higher persistence than daily injectables
• Lower out-of-pocket cost
• Integrated clinical support (nutritionist, behavioral coaching)
• Higher initial weight loss in first 3 months
• Comorbid type 2 diabetes (insurance coverage is better for diabetes indication)

The adherence crisis is not just a patient problem — it's a system problem. Until GLP-1s are affordable, side effects are managed proactively, and patients are educated about the chronic nature of obesity treatment, the gap between what these drugs can do and what they actually deliver at population scale will remain the field's biggest challenge.