People with type 2 diabetes who stopped taking GLP-1 drugs such as Ozempic, Wegovy, Mounjaro, and Zepbound for two years had a 22% higher risk of heart attack, stroke, and death than those who stayed on the medications, according to a study published September 21, 2026, in BMJ Medicine.

That increase largely wiped out the cardiovascular protection patients had built up while on the drugs. The finding comes from researchers at Washington University School of Medicine in St. Louis, who tracked 333,687 U.S. veterans with type 2 diabetes for up to three years.

GLP-1 medications — semaglutide, sold as Ozempic and Wegovy, and tirzepatide, sold as Mounjaro and Zepbound — help lower blood sugar and reduce weight. About one in eight U.S. adults now take them. They also protect the heart, but the new research suggests that protection fades surprisingly fast once treatment stops.

What did the study find?

The researchers, led by clinical epidemiologist Ziyad Al-Aly, compared GLP-1 users with veterans prescribed sulfonylureas, an older class of diabetes drugs that includes glipizide (Glucotrol), glimepiride (Amaryl), and glyburide (Diabeta). Of the participants, 132,551 had been prescribed GLP-1 drugs and 201,136 sulfonylureas.

The team reassessed each patient's treatment status every six months. During the study, 26% of GLP-1 users stopped the medication entirely, and roughly 23% had a gap of at least six months before restarting.

The results showed a clear pattern:

• Continuous GLP-1 use for three years cut the risk of major cardiovascular events by 18% compared with sulfonylureas — about four fewer events per 100 people over three years.
• Stopping after two or two-and-a-half years still yielded risk reductions of 7% and 15%, respectively.
• Stopping before 18 months produced no significant reduction in cardiovascular risk by the study's end.
• A temporary interruption before restarting cut the average benefit from 18% to 12%, with even a six-month gap raising risk by 4% to 8% compared with continuous use.
• One year off treatment raised risk by 14%; two years off raised it by 22%.

Why does stopping hurt the heart?

The study is observational, so it shows associations rather than proof of cause and effect. Still, the mechanism appears metabolic. When people quit the drugs, inflammation, blood pressure, and cholesterol rebound, even if weight regain is the only change patients notice.