By comparison, an 8-ounce cup of coffee has about 100 milligrams; a 16-ounce Starbucks Grande, 330 milligrams. Five of the 16 products that list a specific amount of caffeine—Arizona Energy ...

Adults can safely consume up to 400 milligrams of caffeine daily, which equates to roughly three cups of coffee, says Alissa Steinberg, a registered dietitian and founder of Healthy U. During ...