Caffeine and Dehydration: What’s the Evidence Show?
NEWSLETTER
NEWSLETTER

Caffeine and Dehydration: What’s the Evidence Show?
You may have heard that caffeine is a diuretic, and while this is true it isn’t that straightforward. Simply put a diuretic promotes diuresis, which is an increase in the production of urine. The generally held idea is that a diuretic always causes you to pee more, and thus coffee and black tea should cause you to pee more.
However, we have some pretty robust evidence showing that caffeine amounts of ≤225 mg (1-2 cups of coffee or 5-6 cups of black tea) don’t affect the amount of urine you produce, and do not lead to dehydration. We can’t say for sure what happens above this amount, but it is probably a good idea to switch to a caffeine free option such as
decaf coffee or caffeine free tea.
Submitted by Erik Vandenboer— Dietetic Intern, Mount Saint Vincent University