Why does caffeine dehydrate you?

Answer 1

This is purely anecdotal, of course. I had my teeth bleached by the dentist last Thursday evening and was told to avoid coffee & tea for several days to avoid staining. One day later I had terrible back and hip pain (I was expecting to get headaches!) that prevented me from sleeping, even after taking ibuprofin. On Monday morning, I still had the back & hip pain. After my first (and only) 20oz cup of coffee, the back and hip pain both disappeared.

Answer 2

it is a Diuretic which means that it causes your body to loose water, because it takes more water for your system to process it through the kidneys. Other diuretic drink are soft drinks and tea. Caffeine is a diuretic but the most recent studies have shown that although caffeine causes a mild diuresis, it is similar to that of water. “In the 10 studies reviewed, consumption of a caffeinated beverage resulted in 0 to 84 percent retention of the initial volume ingested, whereas consumption of water resulted in 0 to 81 percent retention.” Additionally, regular consumption of caffeine reduces the diuretic effect unless consumed in large quantities (500-600 mg/day). Of course, this opposes what we have heard for decades and what many will continue to repeat.

Answer 3

Caffeine does not necessarily dehydrate the body's joints. However, it does act a diuretic for some people so can cause dehydration if consumed in excess.