Coffee, Alcohol, and 5 Other Drinks That Can Be More Dehydrating Than You Think

Hydration looks different for everyone. Some people carry a large water bottle around, while others keep it in the back of their mind without thinking too much about it. Then, there are those who may not realize until they return home after a busy day that they’ve barely had any water. Regardless of where you stand, staying hydrated is crucial—and it becomes even more vital as the summer heat sets in.

We all know that water is the top hydrator, but are there drinks that actually contribute to dehydration? Here are some of the most common beverages that can hinder your hydration, along with tips on how to counteract their drying effects, especially when the weather gets warmer.

Staying Hydrated Is Crucial

Staying properly hydrated is essential for our bodies in many ways, especially considering that water makes up more than half of our body composition (about 60%). The benefits of hydration include supporting brain function, joint health, immune system strength, and proper kidney, liver, and gut function. It also helps with detoxification, metabolism, nutrient absorption, and shields the skin, eyes, nose, mouth, and spine from stress and irritants.

While it’s always important to prevent dehydration, it becomes even more critical when temperatures rise, as we’re more prone to losing fluids. Common ways we lose moisture include breathing (who would have thought?), urinating, and sweating, all of which are natural bodily processes. During the summer, we tend to sweat more, which can make us more vulnerable to the uncomfortable symptoms of dehydration.

Dehydration for most people shows up as dizziness, headaches, reduced focus, sleeplessness, fatigue, mood swings, bloating, constipation, dark urine, and infrequent urination.

Severe dehydration can lead to more serious health issues like heart problems, seizures, or organ failure. This extreme level of dehydration is usually the result of severe illness or intense physical activity without adequate fluid intake. However, the hot summer months can also cause us to lose enough fluids to experience heat exhaustion, potentially leading to some of these symptoms if not properly addressed.

Preventing dehydration is straightforward in theory: consume more fluids (and food) than what your body loses each day. But in practice, as many of us know, it's much harder. By the time we feel thirsty, we're already falling behind on hydration, and many Americans experience chronic mild dehydration. The trick to overcoming this is setting small, achievable goals toward a bigger target—like aiming for 8 to 12 cups of water (64 to 96 fluid ounces) or other hydrating drinks daily. Also, remember that many foods, especially fresh fruits and vegetables, can help maintain hydration levels throughout the day.

What Makes a Drink Dehydrating?

Not every drink is as hydrating as it may appear. You might assume that any liquid is automatically hydrating, but that’s not always true. In fact, a lot of the popular drinks we enjoy here are actually quite dehydrating, to some extent. When discussing dehydrating drinks, the diuretic effect comes into play. Diuretics are substances that encourage the body to produce and expel more urine than usual, which can lead to dehydration.

Several dietary components, each with diuretic effects, can contribute to dehydration. Some of these include:

Added Sugars

Consuming added sugar makes the kidneys excrete more fluid. Moreover, when we consume high amounts of added sugar, excess sugar builds up in the bloodstream after the cells take what they need. When substances like salt and sugar become more concentrated in the blood than in the cells, the body draws water from the cells into the bloodstream to balance the concentration of water and solutes (like salt or sugar). In the process, when water is pulled from our cells to dilute blood sugar levels, it leads to dehydration throughout the body.

Excessive Caffeine Intake (Over 500 Milligrams)

Caffeine is a well-known diuretic, and its effects are widely recognized. However, the amount of caffeine you consume is crucial. A 2017 study published in Frontiers in Nutrition found that only caffeine consumption exceeding 500 milligrams (mg) led to diuretic effects. Since an 8-ounce cup of coffee contains around 80 to 100 mg of caffeine, most coffee drinkers may not reach this level. However, other caffeinated beverages like energy drinks can contain twice as much or more, increasing the risk of dehydration and diuresis.

Alcoholic Beverages

On the other hand, we have alcohol—the most commonly consumed depressant. Alcohol acts as a diuretic in several ways and is notorious for causing dehydration. This is one of the major reasons why alcohol often leads to hangover symptoms.

Alcohol is metabolized in the liver, where it produces acetaldehyde and other byproducts. While some of these are expelled from the body via carbon dioxide and water through the lungs (which is why breathalyzers work), others are processed and excreted by the kidneys. Alcohol also suppresses the antidiuretic hormone vasopressin, intensifying its diuretic effect and its potential to cause dehydration.

Some Artificial Sweeteners

Not all artificial sweeteners have the same impact on hydration, but some can significantly contribute to dehydration, mainly due to their effect on digestion. Sugar alcohols like sorbitol, xylitol, erythritol, and mannitol are particularly known for causing a laxative effect, leading to diarrhea, which in turn can lead to dehydration. This is likely because of their ability to alter gut bacteria in the microbiome.

Extremely High Protein Intake

Although more commonly associated with food than drinks, consuming large amounts of protein (a current health trend) can also lead to dehydration. During digestion, protein breaks down into nitrogen, which requires additional water for processing, drawing from our body’s reserves. The kidneys are tasked with removing this excess nitrogen, leading to diuresis and increasing the risk of dehydration.

Common Beverages That Can Lead to Dehydration

Now that we've covered the science, let’s dive into some of the most dehydrating drinks available. This way, you can make the best hydration choices as summer approaches.

You don’t have to completely eliminate dehydrating drinks—they’re a tasty part of life and hard to resist. However, it’s helpful to know which ones are the worst offenders so you can make smarter decisions for your hydration. This knowledge will keep you feeling healthy and energized throughout the summer, when dehydration is a real concern.

1. Coffee

It’s no surprise that coffee takes the top spot on this list of dehydrating beverages, thanks to its caffeine content. But don’t worry, one or two cups of coffee won’t push you into severe dehydration.

Based on the data we have about caffeine’s diuretic effects, you would need to consume almost five cups of coffee a day to experience a significant impact on hydration. If you're someone who drinks more than two cups per day, it’s a good practice to balance each cup of coffee with a glass of water to counter any potential dehydrating effects.

2. Caffeinated Tea and Certain Herbal Teas

While tea generally contains less caffeine than coffee—black tea has about 50 mg per eight ounces—it can still contribute to dehydration if you're drinking large amounts throughout the day. Some herbal teas, especially those designed to treat constipation, can also be surprisingly dehydrating. These teas often contain senna leaves, which have a laxative effect that leads to significant water loss in the body. Keep this in mind when you're browsing the herbal tea section!

3. Regular and Diet Sodas

Soft drinks are notorious for their high levels of added sugar and caffeine, and their diet versions aren't much better due to their artificial sweetener content. Although one study found that cold carbonated drinks might make you feel more hydrated, they actually have the opposite effect, thanks to the diuretic properties of sugar and caffeine. Moreover, if you opt for diet soda, digestive issues can make it even harder to stay properly hydrated.

4. Beer, Wine, and Cocktails

Whether you're enjoying a craft cocktail, sipping on a glass of wine, or cracking open a casual beer, the alcohol in these beverages works as a dehydrator in multiple ways. This is likely the primary culprit behind the headache, dry mouth, and fatigue that many of us experience the morning after heavy drinking. Yes, much of why hangovers feel so awful boils down to dehydration.

To prevent dehydration while drinking alcohol, be sure to drink water before, during, and after each alcoholic beverage.

5. Certain Juices

Depending on the juice variety and its preparation, fruit (and some vegetable) juices can be a hydrating and healthy choice. However, certain juices can actually contribute to dehydration, particularly those that aren't made from 100% fruit and contain added refined sugar. Additionally, some juice ingredients, like celery, contain asparagine, a diuretic amino acid. Beets, while packed with potassium to help regulate water balance, can also promote water excretion when consumed in large amounts.

Lemonade may not be as hydrating as you think. That's because it’s nearly impossible to make lemonade without adding some type of sweetener, whether it’s sugar or an artificial alternative. If you made lemonade using only 100% fruit juice, it would likely be more suited for drizzling on your salmon than drinking as a refreshing beverage. The sweeteners added to lemonade make it less effective for hydration, so it’s not the best choice. (Lemon water, however, is an excellent option for hydration!)

6. Energy Drinks

Energy drinks are a combination of caffeine and added sugars, making them particularly dehydrating. Similar to sodas, energy drinks intensify this effect, given that they contain some of the highest levels of caffeine found in any beverage or food.

7. High-Protein Smoothies

High-protein smoothies, often considered a quick and healthy snack or meal replacement, can actually contribute to dehydration. This happens not only because of the high protein content in some smoothies but also due to the added sugars from ingredients like sweeteners, flavored yogurts, or juices.

How to Enjoy Your Favorite Beverages and Stay Hydrated

So, how can you indulge in your favorite drinks—like lemonade, mojitos, and iced coffee—while still staying properly hydrated?

If staying hydrated is your top priority, limiting or cutting out these drinks might be the most effective strategy. Alternatively, get creative and craft your own versions of these classic beverages at home. For example, try opting for decaffeinated coffee or tea, lower-protein smoothies, water infused with fruits and herbs instead of sugary drinks, or fresh juices packed with hydrators like watermelon, citrus, and cucumber.

Another approach? For each dehydrating drink you consume, balance it with a hydrating one (think: a glass of water!). If you're tired of plain water, go for infused water with cucumber or citrus, flavored seltzers, low-sugar juices, kombucha, or caffeine-free coffee and tea.