Novo Nordisk and Eli Lilly Just Got Some Fantastic News

If the market for GLP-1 drugs wasn't already expanding rapidly enough, makers of these miracle drugs just got news that could accelerate its growth. A study conducted on mice and funded by the National Institutes of Health (NIH) has shown that the GLP-1 drug semaglutide extended lifespan in older, healthy mice by tempering the detrimental effects of aging.

Of course, researchers have long known that calorie restriction can have anti-aging benefits. And GLP-1 drugs are designed to suppress appetite, thereby reducing caloric intake. But the new study, conducted at the University of California, found that the drugs' effects on mice could be more than just a consequence of lower-calorie diets.

In fact, the new study in healthy older mice offers evidence that these drugs may slow physiological aging itself. According to the NIH press release: "Compared with a control group, mice treated with the drug showed improved muscle and cognitive function. Gene expression analysis showed that several hallmarks of natural aging, such as increased inflammation and reduced regenerative capacity, were reduced in treated animals."

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The study in question used the GLP-1 drug semaglutide, which is manufactured by Danish drugmaker Novo Nordisk (NYSE: NVO) and marketed as Ozempic for type 2 diabetes and Wegovy for obesity and chronic weight management.

Eli Lilly's (NYSE: LLY) main GLP-1 drug is called tirzepatide, which it markets as Mounjaro for diabetes and Zepbound for weight loss. Late last year, tirzepatide became the world's best-selling drug, knocking Merck's cancer drug Keytruda out of the top spot.

I assume that semaglutide's anti-aging effects in the study could be replicated with tirzepatide. And that should be fantastic news for both Novo Nordisk and Eli Lilly. Of course, the research remains a long way from establishing the same anti-aging results in humans. But if people believe it might, that will only encourage adoption of the drugs.

The GLP-1 market is already forecast to explode

The use of GLP-1 drugs is growing rapidly. According to polling firm Gallup, Americans' use of GLP-1 injectables for weight loss has nearly quadrupled since 2024. The percentage of U.S. adults taking these weight loss drugs has risen to 11% this year, from 3% just two years ago. And 15% of U.S. adults report having used the medicine at some point.

The drugs are extremely effective at treating obesity. The adult obesity rate in the U.S. has fallen from 39.9% in 2022 to 36.8% in 2026.

J.P. Morgan Global Research forecasts that some 25 million Americans will be on GLP-1 treatment by 2030, up from about 10 million last year. That includes people taking the drugs for type 2 diabetes, but the effects on appetite are the same. And Morgan Stanley forecasts the market for the drugs will more than double from 2025 to 2035, to $190 billion.

The news about GLP-1 drugs just keeps getting better, and the major manufacturers continue to reap massive benefits. I like both of these stocks. While Lilly seems to be winning the GLP-1 race at the moment, Novo continues to develop new products. The potential size of the market for the drugs leaves lots of room for success by multiple competitors.

Matthew Benjamin has positions in Novo Nordisk. The Motley Fool has positions in and recommends Eli Lilly, Merck, and Novo Nordisk. The Motley Fool has a disclosure policy.