Researchers at the Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease found the strongest link between search volume and prescriptions for Wegovy (semaglutide), manufactured by Fortune 500 Europe firm Novo Nordisk, and Zepbound (tirzepatide), made by Fortune 500 pharma giant Eli Lilly & Co. Results of their repeated cross-sectional study were published Jan. 29 in the journal JAMA Network Open.

“Some drugs, like Zepbound, were increasing so steeply, and that surprised us,” coauthor Dr. Philipp Berning tells Fortune. “But [the study] was confirmatory in terms of the GLP-1 agonists…that these more effective drugs took over the field.”

Certain newer OMDs including Wegovy and Zepbound belong to a class of medications called incretin mimetics, so named because they imitate the incretin hormones found in the gut that aid in blood sugar regulation. Wegovy is a GLP-1 (glucagon-like peptide-1) receptor agonist, and Zepbound is a dual GLP-1 and GIP (glucose-dependent insulinotropic polypeptide) receptor agonist. The Food and Drug Administration approved Wegovy and Zepbound in 2021 and 2023, respectively. By comparison, phentermine, an appetite suppressant considered in the study, has been around since 1959.

Researchers used the IQVIA National Prescription Audit and the Google Health Trends Application Programming Interface to analyze data from July 1, 2017, through Feb. 29, 2024—during which more than 69.2 million FDA-approved OMDs were dispensed, with an average annual growth rate of 5.3%.

In the first year, monthly prescriptions rose from 0.76 million in July 2017 to 0.8 million in June 2018. In the final year, prescriptions skyrocketed from 1.29 million in March 2023 to 1.51 million in February 2024, representing 0.41% of all prescriptions that month. OMDs had accounted for 0.21% of all prescriptions in July 2017.

Also in February 2024, the longstanding phentermine was the most popular, with 0.74 million prescriptions. Wegovy had 0.42 million in contrast to Zepbound’s 0.25 million. In Google searches per 10 million, however, phentermine (301.8) trailed Wegovy (636.3) and Zepbound (468.9).

Such robust online search activity surrounding OMDs served as a measure of public awareness, Berning says, which may further influence clinical adoption.

“We definitely believe that the numbers will continue to increase,” he says. “It’s a breakthrough in terms of the efficacy of [incretin mimetics] and controlling obesity.”

As pharmaceutical companies big and small compete to expand their incretin portfolios—for instance, Lilly is hoping to bring a weight-loss pill to market next year and Novo Nordisk recently tested higher-dose Wegovy—Berning doesn’t foresee a decline in parallel googling and prescribing.

That said, the authors noted that the study’s reliance on Google excludes searches on social media platforms and doesn’t take consumer interest as it relates to media coverage into account. Another study limitation is that available data lack details concerning prescription dosing and duration.

Prescriptions down for Saxenda, Contrave, and more

Not all OMDs showed a jump in prescriptions. Throughout the study period, the following drugs maintained fewer than 0.02 million monthly prescriptions:

• Alli (orlistat) by Haleon; available over the counter
• Lomaira (phentermine) by KVK Tech
• Orlistat (generic)
• Xenical (orlistat) by Cheplapharm/H2-Pharma

Monthly prescriptions fell below 0.02 million for Contrave (naltrexone/bupropion), manufactured by Currax Pharmaceuticals, from July 2022 and for Novo Nordisk’s Saxenda (liraglutide) from October 2023.

Generic names for Wegovy, Zepbound gained Google traffic

Wondering why ultra-popular brand names like Ozempic haven’t been mentioned yet? That’s because even though the Novo Nordisk medication contains the same active ingredient as Wegovy, semaglutide, and may help with weight loss, it’s only FDA-approved for people with Type 2 diabetes. The same goes for these diabetes medications, which are often mistaken for OMDs:

• Mounjaro (tirzepatide) by Lilly
• Rybelsus (semaglutide) by Novo Nordisk
• Victoza (liraglutide) by Novo Nordisk

Even so, these incretin drugs experienced a similar boost in online searches and dispensed prescriptions as their OMD counterparts, researchers found. Throughout the study period, Ozempic (2,031.7) and Mounjaro (653.1) had the highest prevalence per 10 million searches. In February 2024, Ozempic and Mounjaro prescriptions reached 2 and 1.2 million, respectively.

Despite the FDA’s warning that unapproved incretin drugs such as compounded semaglutide and tirzepatide can be risky, their popularity too was reflected in the study. In Google searches per 10 million, semaglutide was the clear winner (705.3) in February 2024, followed by tirzepatide (210.5) and liraglutide (17).

Monthly semaglutide prescriptions soared from 0.7 million in June 2021, when Wegovy became FDA-approved, to 2.6 million in February 2024. Similarly, when Zepbound was approved in November 2023, tirzepatide prescriptions jumped from 1.1 million to 1.4 million by February 2024. Liraglutide showed a decline in monthly prescriptions throughout the study period, from 0.33 million to 0.11 million.

For more on weight management:

• Hims & Hers Super Bowl ad slams pricey pharma industry—and fumbles FDA warnings on compounded GLP-1 drugs
• Hate needles? Lilly’s weight-loss pill could get FDA approval next year, CEO says
• Zepbound vs. Wegovy: New clinical trial says this weight-loss medication sheds more pounds
• Most Americans who want to lose weight don’t want to take GLP-1 drugs like Wegovy and Zepbound, new survey says
• The 5 biggest weight loss myths that ‘need to die,’ according to an obesity doctor