How Long People Stay on GLP-1s

This page compiles real-world persistence data — the rate at which patients remain on GLP-1 therapy over time, measured from pharmacy claims and electronic health records. These rates are substantially lower than the completion rates seen in clinical trials, where patients receive the drug free of charge with frequent monitoring.

Reported 12-month rates range from 10% to 63%. The variation reflects methodological choices: how "still on therapy" is defined, which populations and drugs are included, and whether the study counts prescription attempts or only filled prescriptions.

For trial efficacy, see page 1 (clinical trial results). For drug pricing and cost assumptions, see page 2 (costs). For what happens after discontinuation, see page 4 (weight regain).

Higher persistence produces higher total pharmacy spend. Whether sustained use generates medical cost offsets has not yet been demonstrated — Prime Therapeutics found no medical cost offsets through 2 years of follow-up for obesity-only GLP-1 users. See page 5 (ROI) for the full cost-offset evidence.

Among non-T2D patients who discontinued, 36.3% reinitiated within 1 year (Rodriguez et al., 95% CI: 35.6–37.0%). For T2D patients, the reinitiation rate was 47.3%. Weight regain was the strongest driver: each 1% of weight regained increased the hazard of reinitiation by 2.8%.

Gasoyan et al. found that among discontinuers, 19.6% restarted the same medication within 1 year while 35.2% received some alternative obesity treatment (27.4% a different medication, 13.7% lifestyle visits, 0.6% bariatric surgery). Among obesity-only patients, the restart rate was 14.2% — roughly half the diabetes restart rate (23.5%).

Real-world post-discontinuation weight trajectories differ from trial withdrawal data. The STEP 1 extension showed participants regained two-thirds of lost weight within 1 year of stopping; Cleveland Clinic real-world data found obesity patients lost an average of 8.4% before stopping and regained 0.5% at 1 year post-discontinuation. The difference likely reflects real-world patients stopping earlier at lower doses, losing less weight to begin with. For the full weight regain evidence, see page 4 (weight regain).

No study tracks outcomes beyond the first reinitiation event. Cycling (start → stop → regain → restart) is common in real-world data; its cost-effectiveness has not been measured. Each restart involves dose re-escalation (~16 weeks), new prior authorizations, and repeated clinical engagement costs.

No multi-year data exists for post-shortage cohorts. The 62.6% 12-month persistence from 2024 initiators has no 24- or 36-month follow-up. Whether the steep attrition seen in 2021 cohorts will repeat or whether newer cohorts sustain gains is unknown.

Cycling outcomes are unmeasured. The common real-world pattern — start, stop, regain, restart — has no published cost-effectiveness or health outcomes data. No study tracks outcomes beyond the first reinitiation event.

Compounded semaglutide creates a blind spot. Claims-based studies cannot capture compounded GLP-1 use or cash-pay purchases. Patients appearing "non-persistent" in claims data may have continued therapy through these channels.

No randomized evidence compares benefit design strategies. Whether low copays, mandatory counseling, step therapy, or coverage duration limits optimize persistence-adjusted outcomes has not been studied in controlled settings.

The Prime trend data is unreplicated. Persistence doubling from 2021 to 2024 comes from a single PBM's commercially insured book. No other source has published year-by-year cohort trends.

Optimal treatment duration is undefined. The question "how long must a patient stay on therapy to achieve durable clinical benefit?" has no published answer.

Trial-to-real-world extrapolation is rarely quantified. Trial participants were selected and monitored differently than commercial populations. Extrapolating trial efficacy to a broad commercial population requires discounting by persistence, adherence, dose attainment, and patient selection — a compound discount that has not been systematically modeled in the published literature.

Persistence means continuous treatment without a gap exceeding a defined threshold — most commonly 60 days. A patient who fills their prescription every 4 weeks with no gaps longer than 60 days is "persistent." The moment they go 60+ days without a fill, they are classified as having discontinued, even if they restart later.

Adherence is measured as proportion of days covered (PDC) — the number of days with medication on hand divided by the observation period. PDC ≥80% is the standard threshold for "adherent." Unlike persistence, adherence is a continuous measure (0–100%) and captures partial use. The two measures can diverge: at 3 years in the Prime cohort, persistence was 8.1% while mean PDC was 37.5% — reflecting widespread intermittent utilization rather than clean start-stop.

The 60-day gap is the most common standard in published GLP-1 persistence research. Some studies use different thresholds (Do et al.: 135-day; BHI: 2× expected Rx duration; Gasoyan: 90-day). These definitional differences explain much of the variance in reported rates and are flagged throughout this page.

Switching between GLP-1s is generally counted as persistence for employer modeling — switching from Wegovy to Zepbound is not discontinuation from the employer's perspective. Most studies in the master table allow switching; those that don't are noted.

Source quality hierarchy: ★★★★ = peer-reviewed journal with disclosed methods; ★★★ = PBM report or white paper with methods disclosed; ★★ = conference presentation or poster; ★ = industry blog or news article with undisclosed methodology.

All data is drawn from publicly available sources. Conflicts between sources are flagged rather than resolved. Gaps are noted as gaps. This page is reviewed and updated as new data becomes available. Corrections can be submitted via the contact page.