Americans’ voracious appetite for GLP-1 weight loss drugs is driving the country to spend more than $1 trillion on prescription drugs this year, a new report says.
U.S. spending on prescription drugs is projected to increase nearly 13% to $915 billion in 2025 and exceed $1 trillion in 2026, according to an American Society of Health-System Pharmacists (ASHP) report released April 30.
A major reason why the drug’s sales have grown so much: the popularity of the weight-loss and diabetes drugs tirazeptide and semaglutide.
Eli Lilly’s tirazeptide, sold as Zepbound for weight loss and Monzaro to treat type 2 diabetes, is the country’s best-selling drug. The ASHP report projects wholesale purchases of approximately $63 billion in 2025.
Novo Nordisk’s semaglutide, sold as Vegovy for weight loss and Ozempic to treat type 2 diabetes, was second with more than $59 billion last year. ASHP reports that the No. 3 drug, the blood thinner Elixis, reached $29 billion in sales — less than half the amount spent on each other weight-loss drug.
The society analyzed data from a national database that tracks wholesalers’ purchases from drug manufacturers. Wholesalers then sell the drugs to hospitals, clinics, retail and mail-service pharmacies, home health agencies, long-term care facilities, and other health care entities.
The amount consumers pay for prescription drugs varies depending on copays, discounts, and insurance coverage.
Consumers pay less. Drug companies recover more.
Zepbound and Wegovi sales continued to boom, while Lilly and Novo cut prices to lure more cash-paying customers. Surveys show that about half of employer insurance plans now cover anti-obesity drugs. Novo and Lilly have attracted uninsured consumers by selling the drugs directly through their respective pharmacies or through telehealth providers.
“They are a phenomenon,” said Eric Tichy, lead author of the ASHP report and chair of supply chain management at the Mayo Clinic. “The weight loss aspect makes it a phenomenon when pitted against the obesity epidemic in the United States.”
On April 30, Eli Lilly reported strong quarterly revenue and profit growth due to sales of Zepbound and Monjaro – even after cutting Zepbound prices for US consumers purchasing directly from Lilly’s pharmacy. In April, Lilly also launched a weight-loss pill, Foundaio, which it expects to drive further sales growth this year.
Spending on GLP-1 drugs is expected to accelerate further with the launch of weight-loss pills from both companies – Novo’s Vegovy pill and Lilly’s Foundaio. Both companies are betting that daily oral options will appeal to consumers who want to avoid injections or are hesitant to start a weight-loss medication.
Lilly CEO David Ricks told analysts the price cuts have been effective.
“Every time we lower pricing, we see a pretty big spread,” Ricks said.
Although price cuts have enticed customers who pay cash, Ricks said expanding insurance coverage remains important. Earlier this month, Medicare announced a bridge program to open GLP-1 coverage for weight loss from July 1 to December 31, 2027. Under the program, people enrolled in Medicare must pay a $50 monthly copay.
Patients are using more drugs – and not just paying more for them
The ASHP report estimates that U.S. prescription drug spending will increase 10 to 12% this year to more than $1 trillion.
In addition to the GLP-1 increase, total spending is increasing as more patients are using more medications. The report found that about 1% of the increase in spending could be attributed to higher drug prices.
Still, other data suggests price increases remain widespread. As of Jan. 9, companies plan to increase the list prices of more than 850 drugs by an average of 4% over 2025, according to drug pricing nonprofit 46Brooklyn Research. Meanwhile, the prices of some widely used drugs like Eliquis and Jardiance dropped by 43% and 44% respectively.
In 2025, cancer drugs accounted for the largest and fastest growing category of drug spending in clinics and hospitals. Pembrolizumab — sold as Keytruda — was the top-grossing oncology drug in both settings, the ASHP report said.
One factor driving higher prescription use may be changes in Medicare policy. In 2026, Medicare implemented a $2,100 limit on out-of-pocket drug spending for enrollees in Part D, which includes pharmacy and mail-order prescriptions. The cap is part of the Inflation Reduction Act of 2022 legislation that also gave Medicare the power to negotiate drug prices directly with drug companies.
“This could lead to greater use of higher-priced drugs because patients are paying less,” Tichy said.