(HealthDay News) — Some energy drinks appear to significantly improve endothelial function, while other energy drinks and coffee do not, according to a study published in The American Journal of Cardiology.

Janos Molnar, MD, and John C. Somberg, MD, both from the American Institute of Therapeutics in Lake Bluff, Illinois, evaluated the effect of 3 energy drinks and coffee on endothelial function with a device that uses digital peripheral arterial tonometry to measure the reactive hyperemia index (RHI). 

Six healthy volunteers received energy drinks in a random order at least 2 days apart. Drinks studied were 250-mL Red Bull (80 mg caffeine), 57-mL 5-hour Energy (230 mg caffeine), and 355-mL NOS (120 mg caffeine). Sixteen volunteers received a cup of 473-mL coffee containing 240 mg caffeine. Evaluations occurred before drink (baseline) and at 1.5 and 4 hours after drink.

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The researchers found that Red Bull and 5-hour Energy significantly improved endothelial function at 4 hours after drink, whereas NOS and coffee did not change endothelial function significantly.

“Caffeine does not appear to be the component responsible for these differences,” the authors concluded.


  1. Molnar J, Somberg JC. Evaluation of the Effects of Different Energy Drinks and Coffee on Endothelial Function. Am J Cardiol. 2015;116(9):1457-1460.