Caffeine myths, checked
What people believe about their coffee, why it sounds right, and what's true.
No Is coffee bad for you?
Across 201 meta-analyses, coffee went with benefit far more often than harm. The real risks are sugar, unfiltered brews, pregnancy and a cup too late in the day.
Not the way you think If you fall asleep fine, is your coffee fine?
Caffeine barely changes how fast you fall asleep. It takes deep sleep after you're asleep, and diaries counted 41 minutes lost where a monitor measured over an hour.
Sort of Does espresso have more caffeine than coffee?
Ounce for ounce, yes, about five times more. Drink for drink, no. A single shot has about 63 mg and an 8 oz cup of drip coffee about 95.
No Does dark roast have more caffeine?
Brewed the same way, dark roasts came out a little lower in caffeine than light and medium roasts in a 2024 lab study. The bold taste isn't extra caffeine.
No Should you wait 90 minutes after waking for your first coffee?
There's no evidence that coffee right after waking causes an afternoon crash, or that waiting prevents one. The cup that changes your night is your last one.
No Does coffee dehydrate you?
In 50 regular coffee drinkers, four cups a day for three days kept them as well hydrated as the same amount of water. Coffee counts toward your fluids.
Not the way you think Do energy drinks have way more caffeine than coffee?
An 8.4 oz Red Bull has 80 mg, less than an 8 oz coffee. But cans run from 54 to 328 mg per 16 oz, and a 12 oz CELSIUS has 200, about two coffees.
Not the way you think Does cold brew have less caffeine than hot coffee?
It tastes milder, but made with the same coffee and water, coarse-ground cold brew had more caffeine than hot coffee in a 2017 lab test, up to about a quarter more.
Sort of If you drink coffee every day, does it stop affecting your sleep?
Three 150 mg doses a day, ending 8 hours before bed, didn't change sleep in 20 daily drinkers. But a big dose still cut deep sleep 12 hours later in another trial.
Yes, but Does a coffee nap beat coffee or a nap alone?
In a driving simulator, coffee and then a nap of under 15 minutes cut sleepy driving errors to 9% of the placebo level, against 34% for coffee alone. It was 12 people.
