A 16-oz "grande" cup of Starbucks coffee packs a big caffeine punch.
With 330 milligrams of caffeine per cup, the medium-sized drink contains almost the entire "daily safe dose" of caffeine, which is 400 milligrams, according to a report by Chemical & Engineering News and published by the American Chemical Society.
Too much caffeine can be dangerous, according to the report.
“Whereas low dose caffeine effects are wakefulness, a little bit of arousal, and slight euphoria,” Bertil B. Fredholm, emeritus professor of pharmacology at the Karolinska Institute in Sweden, told CEN. “High dose effects are anxiety, irritation, and general mental discomfort—a completely different kettle of fish.”
Past studies have shown that a medium-sized Starbucks has about 100 milligrams more caffeine than the same serving from Dunkin' Donuts.
In extreme cases, excessive caffeine has resulted in heart problems or even death.
Here's a chart, courtesy of CEN, showing where Starbucks and other caffeinated drinks measure up:
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