Does Coffee Dehydrate You? A Detailed Guide To The World’s Most Popular Drink

Caffeine is the most commonly consumed psychoactive drug in the world. Furthermore, it’s the most heavily studied and proven ergogenic aid. It’s the main active ingredient in coffee, tea, energy drinks, and many pre-workout formulas.

Take a look around your local shopping mall, and you’ll be hard-pressed not to find someone sipping on a caffeinated beverage. Whether it's for a social occasion or to get an energy boost when you’re feeling tired, there’s no getting away from coffee in modern-day society. 

With many proven beneficial effects, including better exercise performance and cognition, we can definitely see why. However, as with anything in life, it's important to consider the potential downsides. 

With caffeine acting as a diuretic (something that increases urine production), does caffeine dehydrate you? We explore the answer to this question in detail, looking at coffee alongside other caffeine-containing beverages. Does Coffee Dehydrate You?

If you’re urinating more frequently after drinking coffee, it's totally logical to think that you might start experiencing signs of dehydration. When this happens, you’d need to replenish your electrolytes and water. 

However, while the caffeine content in coffee has a diuretic effect, it’s unlikely to dehydrate you with normal coffee consumption. 

When diving into the research, you actually tend to take in more fluid when drinking a cup of coffee than the amount you lose. Of course, this is slightly different if you’re only drinking espressos, but you get the point. 

If you’re a normal coffee consumer, there’s not much difference to water when it comes to hydration. Our bodies take approximately 1–4 days to build up a caffeine tolerance, including its ability to increase our urinary output. Therefore, regular coffee drinkers will urinate less than those who enjoy the odd cup of coffee!

However, as with everything in life, balance is key. Just because it doesn’t necessarily dehydrate you, doesn’t mean to say you should start chugging liters of coffee. Research shows that you need to consume more than 400 milligrams per day (equal to around 5 cups of brewed coffee) for it to have a significant diuretic effect. Researchers observed that this had a short-term diuretic effect, while lower amounts of coffee were just as hydrating as water. For some of us, we might normally accomplish this by lunchtime! 

In the case that you do start to notice some common symptoms of dehydration, consuming electrolyte-rich foods alongside common electrolyte drinks can help keep your body's water levels in check. You can also make your own electrolyte drinks if you’re looking for cheaper options with more freedom over what's in them. With water making up around 60% of your total body mass, this isn’t something that you should take likely.

So, while coffee might make you urinate more, it shouldn’t dehydrate you in most cases. This is especially the case in habitual coffee drinkers as their bodies have adapted to the diuretic effects of caffeine. If you’re someone who drinks more than 400 milligrams of caffeine every day, it might have a mild diuretic effect. However, this may depend on your individual response. 

If you’re someone who drinks decaf coffee, the answer to “Does decaf coffee dehydrate you?” is still the same. With virtually no caffeine, there’s not even a mild diuretic effect. Drink your decaf coffee, and don’t worry!

To better understand the effects of caffeine and why it's a diuretic, our next section looks at the links between caffeine and hydration.

Caffeine And Hydration 

Coffee is mainly drunk because of its caffeine content, a psychoactive substance that improves focus and aids performance. Caffeine is a diuretic, meaning it causes your kidneys to produce more water-containing urine than usual. Drink your favorite cup of coffee, and more water will leave your body, including important electrolytes!

As we’ve mentioned above, caffeine is the most widely consumed psychoactive substance in the world. You can’t walk for more than 2 minutes down your favorite high street without noticing several coffee shops and supermarkets full of energy drinks. 

Once ingested, the caffeine in your coffee passes through your gut and into your bloodstream. When it eventually reaches your liver, it's broken into several compounds that then exert their beneficial effects. We won’t bore you with the different scientific names for the purpose of today’s article.

Once in the liver, caffeine may increase the blood flow to your kidneys. This is what makes them release more water through your urine, which is why coffee is often thought of as something that dehydrates you. As we’ve discussed above, this is often not the case.

Coffee is often thought to be the main culprit when it comes to caffeine. However, other drinks, such as tea and energy drinks also contain caffeine. Therefore, does tea hydrate you? Let’s answer this in the next section.

What About Other Caffeinated Beverages?

While it's true that coffee is the most commonly consumed caffeinated beverage, it's not the only one. Sometimes, you might like to sit down and enjoy a nice cup of tea with your favorite biscuit. Other times, you might use an energy drink to get you through a hard gym session, physical work day (we’re talking about you first responders), or even a long day at work. 

Here’s a breakdown of the caffeine content in typical servings of coffee compared to other caffeinated beverages:

Tea

Tea contains less caffeine compared to coffee. Therefore, it's considered to be more hydrating with less of a diuretic effect, even when consumed in large amounts. 

The table above shows the average amount of caffeine in a typical tea. However, this will vary depending on the type of tea, brewing method, and steeping time. 

Overall, tea is a pretty good drink to stay hydrated, especially on a cold day if you choose one with a low caffeine content. If you’re only consuming one of two throughout the day, you won't need to worry.

Energy Drinks

The global energy drinks market size was estimated at nearly $80 billion in 2024. By 2030, this number is expected to rise to $125 billion. Basically, their market is huge and isn't going to stop growing any time soon. All you need to do is stroll down your supermarket drinks aisle and you’ll spot the main ones.

Most energy drinks contain a mixture of caffeine, vitamins, and electrolytes. However, a lot of them contain added sugars, which isn't the greatest choice for your health. This is also the case with many commercial sports drinks, even though most of them don’t contain caffeine. 

Even with their high caffeine content, energy drinks are unlikely to cause dehydration when consumed in moderation. Again, this means that 2-3 is generally okay, but don’t start chugging 10 unless you want to land yourself in trouble. The same logic should be applied when deciding how many electrolyte drinks you can consume daily.

If you’re looking to stay hydrated without worrying about the caffeine and added sugar contents, DASH Hydrate may have the answer you’re looking for. Our Sugar-Free Electrolyte packs contain several electrolytes and can be mixed with your favorite foods and drinks for a fraction of the cost of most commercial options.

Is Coffee Your Friend Or Foe?

Coffee contains caffeine, meaning it will likely have a diuretic effect and increase your urination frequency. However, you’ll need to consume excessively large amounts for it to have any kind of dehydrating effect. Even then, some studies show little to no effect, especially in normal coffee drinks. 

The same goes for other caffeine-containing beverages such as tea and energy drinks. They’re unlikely to have any kind of meaningful diuretic effect when consumed normally. In other words, you’ve got nothing to worry about. Enjoy your favorite beverage and try our DASH Hydrate packs if you’re looking to make your own hydration aid at home!