Eli5 How does caffeine dehydrate you?


We all know that caffeine dehydrated you but how does it exactly work? For instance. If I drink an energy drink and immediately follow that with water does the water get absorbed properly or is there some sort of caffeine window?

In: 6

Caffeine will stimulate certain parts and functions of your body. One of these functions is diuresis, which is the expulsion of water from your body via your kidneys and bladder. So it makes you pee more, which is how it dehydrates you. If you drink water afterwards, that can make up for the loss (depending on how much water you drink and how much caffeine you just ate/drank).

Caffeine doesn’t dehydrate you. It is a mild diuretic, meaning you pee more. But the liquid you are consuming still hydrates you more than you’re losing.


Drinking normal coffee doesn’t dehydrate a normal person. The mild diuretic effect of caffeine will be more than offset by the water in the coffee in the first place. This is a made up outcome.

AFAIK, caffeine increases your blood pressure, and that’s how it’s diuretic. I.e. your blood vessels contract, more liquid is pushed out of them. Any substance that increases your blood pressure will have at least mild diuretic effect.

when it comes to coffee it doesnt.

caffeine has a mild diuretic effect but generally is offset by the aater you need to consumed to ingest said caffeine(unless you are somehow freebasing caffeine).