Shares of Monster Beverage fell after new research indicated that energy drinks may increase blood pressure and disturb the heart's rhythm.
The company has come under mounting pressure from critics regarding potential health risks of Monster Energy, the top-selling U.S. energy drink.
The company's shares were trading down following the news. (Click here to track Monster's stock after the report.)
The research, which analyzed seven previously published studies and was presented at an American Heart Association meeting, found an increase of 3.5 points in systolic blood pressure for those consuming energy drinks.
"The correlation between energy drinks and increased systolic blood pressure is convincing and concerning, and more studies are needed to assess the impact on heart rhythm," said Sachin Shah, the lead author of the report and an assistant professor at the University of the Pacific in California.
Monster was not immediately available for comment.
Earlier this month, the company said its medical investigators found no evidence that the drink caused the death of a teenage girl in Maryland.
The girl's family sued Monster last year, blaming her cardiac arrest on "caffeine toxicity" brought on by consuming two Monster Energy drinks in a 24-hour period.
The authors of the new research also found that the QT interval was 10 milliseconds longer among those who had just consumed one to three cans of energy drinks.
A prolonged QT interval, which describes a segment of the heart's rhythm on an electrocardiogram, can cause serious irregular heartbeats or sudden cardiac death.
"Patients with high blood pressures or long QT syndrome should use caution and judgment before consuming an energy drink," Shah said.