A new study is raising concerns about the potential heart risks associated with caffeinated energy drinks and stimulant supplements, particularly among younger adults.
Researchers reviewed more than 28,000 adverse-event reports submitted to the FDA between 2017 and 2025. Products containing caffeine or other stimulants appeared disproportionately often in reports involving serious cardiovascular events, including cardiac arrest and heart attacks.
About 45% of reports linking caffeine- and stimulant-containing products to cardiovascular events involved adults ages 18 to 34 — a group not usually considered at high risk for heart attacks or cardiac arrest.
The analysis found cardiac arrest was reported about 11 times more often in connection with caffeine- and stimulant-containing products compared with products without those ingredients.
Reports involving energy drinks and supplements were about 4.5 times more likely to include heart attacks and four times more likely to include ventricular arrhythmias or heart palpitations.
Dr. Brian Downey, director of General Cardiology Services at Tufts Medical Center in Boston, Massachusetts, said the findings are notable.
“That’s quite a bit higher than we would expect to see,” Downey said.
He also cautioned that the FDA database is voluntary, meaning not every patient who experiences an event submits a report.
Downey said the potential concern may involve a combination of the amount of caffeine and other ingredients in these products.
A 20-ounce energy drink can contain the caffeine equivalent of as many as four or five cups of coffee, he said. The study also notes that some energy drinks contain three times as much caffeine per fluid ounce than brewed coffee.
Exercise and other factors that increase heart rate may also contribute to the risk of abnormal heart rhythms or heart attacks.
Researchers said the reasons for the pattern among younger adults aren’t fully understood. Possible factors include how frequently young adults consume these products; whether they use them before intense exercise or with alcohol or drugs; or whether some people have an undiagnosed heart condition.
The American Heart Association says up to 400 milligrams of caffeine per day is generally safe for most adults. But some people can quickly exceed that amount with energy drinks or stimulant supplements.
Downey said moderation is key, particularly for teenagers.
“Having an occasional energy drink is probably not the end of the world, but being prudent with how much and how often is probably a good idea,” he said.
He also recommends considering more natural sources of caffeine, such as coffee or tea, and consuming them in moderation.
“A cup or two of coffee a day or something in the afternoon is probably fine,” he said.
The AHA acknowledges the study has not been peer-reviewed and does not prove that caffeine or stimulant products caused the reported heart events.
Its experts say more research and systematic safety monitoring are needed to better understand the relationship between these products and cardiovascular conditions.
For now, consumers can pay attention to how much caffeine they’re getting, how often they’re using stimulant products, and whether they experience symptoms such as chest pain, palpitations or fainting.
