How much caffeine is dangerous to human health? Like, hypothetically, if I add 6 teaspoons of coffee concentrate to my oatmilk, and each teaspoon contains at least 80mg of caffeine, that means I'm consuming upwards of 480mg in a day and my brain is perpetually playing that song at the end of Hereditary. Hypothetically. Anyways asking for a friend who may or may not have been consuming half a gram of caffeine daily for the past week...totally a friend...