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Why Does Coffee Make You Pee? Diuretic Effects Explained

person needs to pee

We’ve all been there. Maybe a cup and a half of your favorite drip coffee, you’re having a great conversation with your friend, and you start crossing your legs. You’re getting antsy. Is it the caffeine making you jittery? Nope! You’ve got to pee!

Why does coffee do this? And it seems like it comes on all of a sudden. Why? Let’s take a look at why one of the world’s most popular beverages.

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How Caffeine Affects Your Body

It goes without saying that the main stimulant in coffee is caffeine. But for as obvious as this is there are several misconceptions about the world’s most popular drug. Some of these misconceptions are that caffeine is inherently addictive, it causes insomnia, and it is linked to cancer. But one misconception that is particularly relevant for us is that caffeine makes you dehydrated.

While it is true that large amounts of caffeine will have you reaching for your water bottle, moderate use is generally considered to have little to no effect on how hydrated you are. Part of this misconception stems from the fact that caffeine is a mild diuretic, meaning that it promotes increased urination. According to this view, if caffeine as a diuretic causes you to lose more fluid than you are putting into your body (You drink a 6 oz. cup of coffee and pass 8 oz. of urine), then you are becoming more dehydrated. But this is not so. One study suggests that you can consume up to four cups of coffee per day without any detrimental effect on overall fluid balance.

woman drinking coffee
Image Credit: Pixabay

Caffeine As a Diuretic

Coffee has been consumed by humans (and goats!) since at least the sixth century. But caffeine was not isolated from the coffee bean until about 1820 when Friedlieb Ferdinand Runge was tasked with discovering what exactly in the magic bean was getting people hyped up. This discovery would later lead to the possibility of decaf coffee (a tragic tale for another day).

Since then, it has been discovered that caffeine is the diuretic element of coffee. We know that diuretic causes increased urination, but how exactly does it work?

Diuretics are often proscribed by doctors for kidney issues and high blood pressure. This is because diuretics help release sodium into your urine. The sodium takes more water from the blood as a consequence. Lower sodium levels help kidney health and reduce blood pressure at the same time.

This is why caffeine is often linked to overall lower blood pressure (albeit a small decrease) even though while it is in your system it can raise your heart rate.

hands holding a cup of coffee
Image Credit: Pixabay

Why Does Coffee Make My Pee Smell?

If your pee smells like coffee (let’s hope your coffee doesn’t smell like pee) then you are probably drinking too much coffee. This could be an indicator that you are at least mildly dehydrated. Good fluid balance will not lead to pee smelling like coffee. If you are not getting enough water, then your urine will be more concentrated. If the fluid that you are putting into your body is coffee, the antioxidants (specifically, polyphenols) in coffee that are usually absorbed by your digestive tract will not be completely absorbed. These polyphenols are the thing that is largely responsible for the smell of coffee.

Why Does Coffee Make You Poop?

If you have ever had to pee like a racehorse due to caffeine consumption, you’ve surely had to scramble to find a toilet for a number two due to the same. We know the story. You wake up early and have your first cup on the way to work. Then your stomach starts to growl. You think, “I’m not hungry, I just ate breakfast!”

Then you realize. I’m not hungry. Storm’s a-comin’. Let’s hope you work in an office because if you don’t, you’ve got an emergency on your hands. Your boss chews you out because you missed the morning meeting and you sheepishly respond, “I had something personal to tend to.”

Why does coffee make you poop? Can the urge to go be managed or subdued?

Coffee makes you rush to the restroom because caffeine relaxes muscles in your digestive system. It relaxes the lower esophageal sphincter which can cause reflux and heartburn in excess amounts. But it also relaxes the muscles in your colon. This is why, shall we say, it comes with relative ease after a cup of coffee.

In addition to the caffeine relaxing some intestinal muscles, the chlorogenic acids in coffee can also increase stomach acid which expedites digestion.

If you’re trying to avoid the rush to make your daily deposit too early, try switching to a darker roast of coffee. Dark roast coffee generally has less acidity and sometimes less caffeine than medium or lighter roasts.

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Final Thoughts

In general, “everything in moderation” is a good axiom to follow when it comes to your diet. Coffee is delicious. No doubt. But if your morning trips to the bathroom, whether number one or number two, are interfering with your daily routine, you might want to consider dialing it back a bit. Cut back a bit and you’ll enjoy savoring it more as well.


Featured Image Credit: Pixabay


Aaron Rice

Aaron is a Pacific Northwest native who enjoys coffee, playing guitar, and playing cribbage with his wife. He is currently a graduate student in Boston, Massachusetts.

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