Total U.S. spending on glucagon-like peptide-1 receptor agonists increased by more than 500% from 2018 to 2023, with substantial growth in semaglutide and tirzepatide products, according to new research.

The study, conducted by researchers from the American Medical Association and the Centers for Disease Control and Prevention, found that spending on these medications rose from $13.7 billion to $71.7 billion during the study period. The most dramatic growth occurred between 2022 and 2023.

Key Findings

Total spending on glucagon-like peptide-1 receptor agonists (GLP-1 RAs) increased at a mean annual rate of 34% from 2018 to 2022, then accelerated to 62% growth from 2022 to 2023. By 2023, products containing semaglutide (Ozempic, Rybelsus, and Wegovy) or tirzepatide (Mounjaro) accounted for 70% of all GLP-1 RA spending.

"This study estimated that more than $71 billion was spent on GLP-1 RAs and more than $50 billion on a product based on either semaglutide or tirzepatide molecules," the investigators wrote in JAMA Network Open.

The analysis showed that spending patterns varied considerably by product:

• Semaglutide (Ozempic) spending increased from $0.4 billion to $26.4 billion
• Dulaglutide (Trulicity) rose from $5.6 billion to $17.6 billion
• Combined spending on liraglutide (Victoza) and exenatide (Bydureon, Byetta) decreased from $7.1 billion to $3.1 billion
• Liraglutide (Saxenda) spending increased slightly from $0.6 to $0.9 billion

Products with FDA approval for type 2 diabetes accounted for 89% of all GLP-1 RA spending in 2023, while products approved for obesity treatment represented 11% of spending.

Market Share Shift

The market share of GLP-1 RA products shifted dramatically over the study period. From 2018 to 2023, dulaglutide (Trulicity) declined from 41% to 25% of total spending, while the combined share of liraglutide (Victoza) and exenatide (Bydureon, Byetta) fell from 52% to just 4%.

By 2023, the two products released since 2021—Mounjaro and Wegovy—had captured 17% and 10% of market share, respectively.

Study Methodology

The researchers analyzed Symphony Health data for adults aged 18 years or older, which captured 85% of retail and 74% of mail order prescription fills. The spending figures represented amounts directly spent by patients and insurers at the point of sale, adjusted for inflation using 2023 dollars.

The researchers noted several limitations to their analysis. The study did not capture sales at compounding pharmacies or prescription indications. Additionally, the figures could not be adjusted for rebates, discounts, or price concessions, which "vary across manufacturers and can be substantial, especially on newly released products."

"Manufacturer discounts for GLP-1 RAs prior to the introduction of tirzepatide have been estimated to be as much as approximately 40% to 60%," the researchers noted. "Although this study's results suggest dramatic increases in net spending on GLP-1 RAs, the actual spending is likely somewhat lower than our estimates."

The study did not include tirzepatide (Zepbound), which was approved for obesity treatment in November 2023.

The researchers concluded that "expanded indications and coverage determination in future years could continue to drive demand and spending," noting that factors such as "challenges in long-term adherence, spending in competition with other health care costs, lack of price transparency, and the integration of new products and indications will continue to drive demand for ongoing research in this area."

Author Insights

In an exclusive interview, lead author Stavros Tsipas, MA from the American Medical Association, addressed questions about the study's findings and limitations.

When asked about potential changes in manufacturer discount structures with the entrance of tirzepatide into the market, Tsipas noted data limitations prevented such analysis. "Within this study, data are not available and hence, we were unable to adjust our spending estimates for any rebates, discounts, or price concessions," he explained.

Similarly, regarding the challenge of distinguishing between on-label and off-label prescribing patterns—particularly for products like Ozempic that showed dramatic spending increases—Tsipas confirmed methodological limitations. "Because of data limitations, we were unable to observe the indication for the prescription. Data are not sufficient to develop a methodology to distinguish between on-label and off-label uses," he stated.

These responses highlight the challenges researchers face in fully capturing the economic impact of GLP-1 RAs, particularly as their usage expands beyond their primary indications.

The researchers concluded that "expanded indications and coverage determination in future years could continue to drive demand and spending," noting that factors such as "challenges in long-term adherence, spending in competition with other health care costs, lack of price transparency, and the integration of new products and indications will continue to drive demand for ongoing research in this area."

No competing interests were declared.