Skip to main content

Does coffee dehydrate you? Debunking this common misconception

Understanding coffee's effects

Small coffee cup and saucer
Maani Collection / Shutterstock

Every coffee drinker has reached a point where they realize they’ve consumed about three or four cups of coffee and almost no water in a day. At this point, the notion that coffee dehydrates you may run through your head, reminding you to grab a glass of water. While drinking enough water is critical regardless of coffee consumption, the concept that coffee dehydrates you is not entirely true.

The misconception stems from the idea that coffee is a diuretic, which is true. However, are these diuretic effects enough to cause symptoms of dehydration? In this guide, we’ll break down everything you need to know about the question, “Does coffee dehydrate you?” Is this common belief made up, or is there some truth to it? Let’s explore.

Recommended Videos

Does coffee dehydrate you?

Espresso cup with a book and coffee beans
Engin Akyurt / Pexels

While coffee is a diuretic, that doesn’t necessarily mean it dehydrates you. Coffee’s caffeine content increases the amount of urine your body produces, which can increase the amount of fluids you lose. This process creates a mild diuretic effect, helping your kidneys to draw out extra salt and water. However, coffee is made of nearly 95% to 98% water, so the diuretic effects are mild. All in all, this means that the short answer is no, coffee does not dehydrate you.

Developing a tolerance

Man drinking coffee while working on a laptop
Andrea Piacquadio / Pexels

The question “Does coffee dehydrate you?” also goes hand in hand with a few other key points. Most people who regularly consume coffee also begin to develop a tolerance. Habitual coffee consumption causes your body to adapt to regular coffee consumption, further impacting the diuretic effects of coffee. Over time, your body will adjust its fluid regulation mechanisms to reduce the amount of sodium and water lost. Studies have examined these effects, too, concluding that regular coffee drinkers experience little to no diuretic impact.

A study of 50 men who regularly drank coffee divided participants into a water-only group and those who drank both water and coffee. Overall, the researchers found almost no difference between the two groups. While this doesn’t mean you should completely disregard the idea that coffee could dehydrate you, it means you shouldn’t have much to worry about if you have just one or two cups daily.

Drinking too much coffee

Coffee next to a laptop
Pixabay / Pexels

All in all, the casual coffee drinker is unlikely to drink enough coffee to become dehydrated. The FDA recommends that adults consume no more than 400 milligrams of caffeine daily. On average, a regular cup of coffee contains about 95 mg of caffeine (per 8 ounces), so it would take quite a few cups of coffee to reach the 400 mg limit.

However, many other coffee drinks, such as nitro cold brew or espresso drinks, can contain upwards of 200 mg per cup. At national coffee chains like Starbucks, extra-large sizes like venti sizes of some drinks can include even more than 200 mg of cup. With this in mind, it’s easy to see how you could accidentally consume too much caffeine daily.

As long as you stay under this limit, your coffee consumption will not likely cause dehydration symptoms. However, if you’re consuming more caffeine than you think, you could be at risk for symptoms of dehydration. Some signs and symptoms of dehydration include fatigue, confusion, dizziness, and headaches. You might also notice excessive thirst, dry mouth or lips, or dark-colored urine. Always see a doctor if you notice any signs of dehydration.

Suppose you think you’re about to consume 400 mg of caffeine (or are starting to develop symptoms of dehydration). In that case, switching to decaf or limiting caffeine consumption may be worthwhile to avoid dehydration.

How to avoid coffee’s diuretic effects

Cold brew coffee
ROMAN ODINTSOV / Pexels

The best way to avoid experiencing coffee’s diuretic effects is to limit your consumption to one to three cups daily. However, this can be challenging for those with busy schedules or who love sipping delicious coffee all day. While switching to decaf is an option, some coffee lovers say the decaffeination process may impact the flavor. In these cases, switching to half caff coffee is a great idea to allow you to enjoy the taste of coffee you love with a lower caffeine content. You can also adjust the type of coffee you drink, as some coffee, such as light roast, may contain more caffeine than dark roast coffee.

If you reach for (another) coffee, it might be time to space your caffeine throughout the day and consume water in between. If you use coffee as a pre-workout for an energy boost, drink plenty of regular water throughout your workout.

Emily Caldwell
Emily is an accomplished freelance journalist focusing on food, beverage, health, fitness, and travel content. She loves to…
Is espresso bad for you? Here’s what experts say about its health effects
Does drinking espresso pose health risks?
espresso mugs

Studies and news headlines every other day seem to alternate between the positive and negative effects of drinking coffee, leaving many coffee drinkers confused. But few headlines examine espresso specifically. Espresso is a delicious concentrated form of coffee and is a personal favorite of mine. But how does the caffeine in espresso affect you? Is espresso bad for you?

I spoke with Ashley L. Madsen, PA-C, HHC, ABAAHP, Clinical Director of Ethos Aesthetics + Wellness, to learn how drinking espresso affects our health. Madsen shared her thoughts on "Is espresso bad for you?" along with some insight backed by medical research. Here's what she had to say.
Is espresso bad for you?

Read more
How to make a cappuccino: A 5-step guide for beginners
Craft a smooth and balanced cappuccino at home
Cappuccino with a design in the foam

The balanced nature of a cappuccino, made with equal parts espresso, steamed milk, and milk foam, is what makes the drink my favorite espresso drink. Drinking a cappuccino feels like a good mix between indulgent but not too indulgent and creamy, like a latte.

The smooth, creamy espresso drink is a go-to order for when I don't want a black Americano, yet I feel like ordering something more sophisticated than a coffee with cream. I've loved to order a cappuccino for years, but I only recently started to explore how to make a cappuccino at home. Here's what you should learn to brew this classic favorite at home.
How to make a cappuccino

Read more
Verve Coffee Roasters launches new Wilder Blend, inspired by California’s Wilder Ranch State Park
Celebrate the beauty of nature in your cup of coffee
Verve Coffee Roasters

Verve Coffee Roasters has recently launched its latest Wilder Blend, inspired by California’s Wilder Ranch State Park. The Santa Cruz-based specialty coffee roaster celebrates nature's beauty with its fan-favorite seasonal blend, Wilder. The Wilder Blend highlights three different regions: Guatemala, Rwanda, and Peru. With notes of pluot, cherry leaf, and dandelion, the coffee results in a jammy upfront, rounding out into a delicate balance with a finishing floral touch. Each sip captures the spirit of the land to your cup, echoing serene trails and coastal breezes.
Wilder is now available in both the company's cafe locations in California and via online purchase for home brewing. The blend can also be brewed in various ways, including Verve’s Dwell Dripper - crafted from BPA-free silicone and features a unique bottomless design, allowing for a free-flowing brew process that creates an aromatic and beautiful brew. Effortlessly clean and endlessly enjoyable, this new blend can be purchased in whole bean form, finely ground form for espresso, medium for filter brewing, and coarse for French press brewing.
According to Verve Coffee Roasters, all of the brand's coffee roasts can be brewed in multiple ways, designed for your perfect morning. You can also try the Wilder Blend in Instant Coffee form to enjoy your coffee on the go. Individual packets are ideal for travel and require only 10 ounces of hot or cold liquid  (water, milk, or milk alternative) to make. Simply stir and drink up (perhaps while hiking in the Wilder Ranch State Park). This limited-time seasonal roast is available now for purchase.
Buy Now

Read more