Why Does Coffee Make You Pee?

In the United States, over 50% of American adults divulge in their morning routine with a warm cup of joe to get them started. This is equivalent to 150 million people every day just in the United States alone. According to the National Coffee Association, the average American drinks 3.2 cups of coffee a day. That’s over 1,168 cups of coffee a year. It’s no wonder why the United States coffee market is worth over 18 billion dollars annually.

Point being, if your’re American…you probably drink the jitter juice to start off your morning. You may have noticed after you finish a cup of your favorite brew, that sudden urge to urinate. So why does this happen? Well, it all starts with the way caffeine affects your brain.

Along with giving you a jolt of mental focus, caffeine also inhibits the production of a hormone called the anti-diuretic hormone or ADH. ADH is secreted by the pituitary gland of the brain, which sends the hormone through the bloodstream and into the kidneys. There, the ADH  signals the kidneys to produce aquaporins.

Aquaporins are responsible for absorbing water within the kidneys and distributing water into the bloodstream so the rest of the body can be rehydrated. The release of ADH by the pituitary gland means the body is thirsty and needs to be quenched.  

Caffeine affects the process of hydration because it is a diuretic. This means that when you drink coffee, it causes the body to send signals to your pituitary gland that inhibits the production of the ADH hormone, which in turn causes the kidneys to not reabsorp water. This will increase the excretion of water via urine. This is the reason you have to urinate after you enjoy coffee.