Is Coffee a Diuretic?

The caffeine in coffee can serve as a diuretic.
People who drink coffee on a regular basis are less likely to notice its diuretic effects.
Diuretics can affect blood pressure levels.
Coffee can cause those who drink it to urinate more frequently.
Because coffee is a diuretic, a cup or two a day may aid in weight loss through the decrease of water weight.
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  • Written By: Chad J. Smith
  • Edited By: Angela B.
  • Last Modified Date: 04 March 2015
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A diuretic is any drug or compound that increases the rate of urination, an effect a person can experience first-hand when drinking a cup of coffee or two. You have some coffee and, soon enough, you have to use the restroom. This makes coffee a diuretic.

Specifically, it is the caffeine in the coffee that makes coffee a diuretic. Coffee is a natural diuretic, along with some kinds of tea and other foods. How much the diuretic effects will apply to you will depend on variables such as personal tolerance, weight, and age. Other variables that make coffee a diuretic are just how much caffeine your particular type of coffee contains and how much coffee you actually drink. If you don’t normally drink coffee and you have a couple of strong cups of caffeinated coffee in the morning, then you’re probably going to need to use the restroom a little more often, and with greater urgency, than you normally do.

Underlying the questions about coffee’s diuretic properties is the concern that it may somehow be harmful, because one may actually become dehydrated as a result of drinking too much coffee and, thus, urinating too much. Research demonstrates that a little coffee is not harmful, and the concern over dehydration is unfounded. In reality, it is probably the urgency with which one needs to relieve himself that causes the concern.


Caffeine is a stimulant that increases and expedites the need to use the restroom, but it doesn’t actually cause you to expel more urine from your system than you normally would. A cup of coffee is mostly water, so the diuretic effects may be offset by the water being consumed in the process of drinking the coffee. With that said, drinking enough plain water every day is part of a healthy routine, and you should replace what you lose.

The natural caffeine found in every cup makes coffee a diuretic. If you don’t normally drink coffee or don’t consume other caffeinated beverages, then a cup or two of coffee with have noticeable diuretic effects on your system. You’ll feel the pressure to urinate more strongly and you may even feel as if you’re urinating a larger volume than normal. Regular coffee drinkers, however, are less likely to notice the beverage's diuretic effect. The diuretic effects of coffee will be insignificant as a result of the regular coffee drinker’s tolerance of caffeine.



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Post 3

@burcidi-- That's exactly right. Coffee doesn't make the body produce more urine, it just makes urine leave the body faster. It does this by stimulating urination. So that is the reason why coffee doesn't really carry the risk of dehydration like the over-the-counter or prescription diuretics.

@fify-- That's a good question. One reason could be that the type of caffeine in coffee is different than the caffeine in tea. Plus there is just more caffeine in coffee. I can never have coffee at night for this reason, but can have black tea without having any trouble sleeping.

I'm not sure how accurate this is, but I've heard that this diuretic effect of coffee might also be caused, or

at least increased by the oils in coffee. Different people might also react to it differently. For example, I don't really drink more water like you do when I have coffee. But coffee does stimulate bowel movements with me, which it may not do for other people.
Post 2

Okay, so, coffee makes us urinate more, but it doesn't increase urine output? How does that work?

Does coffee just quicken urination? The amount of urine that would leave our body by, let's say, midnight, will leave by the afternoon?

Is this what this means? If it is, then coffee is not "diuretic" in the same sense that diuretic water pills are. I believe water pills actually increase urine output (not just quicken it) and they have a risk of dehydration.

Post 1

I'm a big coffee drinker and I believe that coffee has health benefits. But coffee does make me go to the restroom more because it makes me drink more water.

I had no idea that coffee is diuretic and always wondered why I drink so much water after having coffee. For every one cup of coffee, I have an extra two glasses of water. It's this extra water that makes me go to the bathroom more.

If I didn't drink more water with coffee, I don't think I would go to the restroom more than usual. But I'd probably be dehydrated because it makes me so thirsty!

Black tea makes me thirsty too, but not as much as coffee does even though they both have caffeine. Does anyone know why?

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