If you manage a health plan budget, one drug class is now doing more to move your numbers than anything else on the formulary. According to IQVIA, GLP-1 therapies account for nearly half of all growth in prescription drug sales. That figure came out of a keynote by Scott Biggs, director of supplier services at IQVIA, at the Pharmacy Benefit Management Institute annual meeting in Orlando.
The size of the category explains why. On the diabetes side, GLP-1s such as Mounjaro and Ozempic represent a $98 billion market growing 16.5% year over year. On the weight loss side, products such as Zepbound and Wegovy generated $55 billion over the last 12 months, a 75% jump year over year, in a category that was effectively nonexistent in 2022. Combined, that is roughly $153 billion in annual spend concentrated in a single therapeutic class.
That growth has crowded out older diabetes spending. Insulin products now make up 9.8% of the diabetes market, down from 38.4%, a drop of nearly 29 percentage points. By prescription count, insulin fell from 21% of fills to 16%. Treatment patterns in diabetes have shifted, not just pricing.
Pharmacies have changed their posture too. A year ago, roughly 48.5% of independent pharmacies declined to fill weight loss GLP-1 prescriptions. That number is now 35%, and only 8% refuse diabetes GLP-1 prescriptions. Biggs described independents as beginning to accept the weight loss products rather than turning them away. Retail still handles about 80% of the GLP-1 market, though mail delivery has climbed to 12.9% of prescriptions as direct to consumer channels grow.
Medicare is now a factor as well. CMS launched a Part D demonstration called the Bridge program on July 1, 2026, giving certain beneficiaries access to Wegovy, Zepbound, and Foundayo for a $50 copay. Biggs said 9,000 claims were paid in the first three days, which he estimated at close to $2 million in CMS spending over that short window.
The pipeline suggests this is early. Biggs said roughly 200 molecules are in development. Near term work focuses on reducing side effects, improving tolerability, preserving muscle mass, and producing greater weight loss either alone or in combination therapy. Longer term research is looking at prostate cancer progression, endometrial and other obesity related cancers, fertility and PCOS in women’s health, and inflammatory pathways tied to respiratory and neurodegenerative conditions including dementia and Alzheimer’s disease. Trials are also examining whether GLP-1s can improve depressive symptoms and reduce alcohol consumption, opioid overdose risk, and tobacco use.
The broader drug trend data from IQVIA’s 2026 Use of Medicines Trend report fills in the backdrop. Total prescription medicine use rose 1.5% in 2025, reaching 210 billion days of therapy. The U.S. market grew 10.6% at net prices in 2025 and has averaged 9.3% annual growth over five years. Patient out of pocket costs hit a record $110 billion, up $6 billion from the prior year. Going forward, patent expirations and pricing pressure are expected to slow growth through 2030, with spending forecast to rise 4.5% to 7.5% at net prices and 6% to 9% at list prices.
For employers, the practical question is no longer whether GLP-1s will show up in your claims data. It is how your plan handles coverage criteria, prior authorization, and cost sharing for a category that keeps expanding into new indications. Plan designs written before this category existed are the ones most likely to produce surprises at renewal.
Note: the source article states weight loss GLP-1 sales rose from $2 million in 2022, while its own summary says near zero. I wrote it as effectively nonexistent to avoid repeating the conflict. Tell me which figure you want and I will set it.