Health Wellness Does Coffee Dehydrate You? We Asked Dietitians It's not as detrimental to hydration as you might think. By Samantha Lande Samantha Lande Samantha is a freelance writer who covers health, nutrition, wellness, and has contributed to national and international publications for over a decade. Real Simple's Editorial Guidelines Updated on February 10, 2024 Fact checked by Isaac Winter Fact checked by Isaac Winter Isaac Winter is a fact-checker and writer for Real Simple, ensuring the accuracy of content published by rigorously researching content before publication and periodically when content needs to be updated. Highlights: Helped establish a food pantry in West Garfield Park as an AmeriCorps employee at Above and Beyond Family Recovery Center. Interviewed Heartland Alliance employees for oral history project conducted by the Lake Forest College History Department. Editorial Head of Lake Forest College's literary magazine, Tusitala, for two years. Our Fact-Checking Process In This Article View All In This Article Overview Exceptions Hydration Tips FAQs According to the National Coffee Association, 62 percent of Americans drink coffee daily, with the average coffee drinker consuming more than three cups each day. Beyond its ability to wake you up, coffee has numerous health benefits, so it's no wonder it's a beloved beverage. But if you tend to sip more coffee than water throughout the day, you might be asking the question: Does coffee dehydrate you? Read on to figure out exactly how your coffee habit is affecting your hydration levels. Ilisa Nussbaum, a distinguished Registered Dietitian Nutritionist certified by the state of Connecticut, is the owner of IN Nutrition. Marie A. Spano, MS, RD, CSCS, CSSD, is a leading sports nutritionist, having served major league teams, minor league affiliates, and MMA teams. Hydration Impact for Regular Coffee Drinkers "The impact of coffee on hydration is a super common question," says clinical dietitian Ilisa Nussbaum. "We always joke that nutritionists start each answer with 'it depends,' but it's true for this question." If you're concerned about your morning cup of Joe, you need not worry too much if you drink coffee daily. "Anyone who regularly consumes caffeinated coffee or tea will develop a tolerance, and a regular cup of coffee has no real significant effect on overall hydration status," says registered dietitian Marie Spano. Studies have shown that drinking two to four cups of coffee (around an 8-ounce size cup—we're not talking Venti here) had little impact on hydration for the regular coffee drinker. The caffeine in coffee is a diuretic, but with regular consumption of coffee, that diuretic effect actually decreases, having minimal impact on urine output. While coffee does have a diuretic effect, drinking one or two cups likely won't lead to dehydration. According to experts, you would have to drink more than 500 mg of coffee per day—about six cups—to induce a substantial amount of dehydration. Hydration Impact for Casual Coffee Drinkers While the diuretic effect of coffee decreases with regular coffee consumption, the casual coffee drinker may feel more of a dehydrating impact. They simply don't have the same level of tolerance as a more frequent coffee drinker. However, the impact isn't too intense. "In those who don't regularly consume caffeine, drinking two to three cups of coffee will lead to a very short-term and minimal increase in urine output," Spano says. It's important to pay attention to what you feel like when you're not used to drinking coffee. For example, if you're taking more trips to the bathroom (for number one or two), you may want to increase your fluid intake to replenish. When a habitual coffee drinker goes sans caffeine for a few days, they should treat it more like they're a casual drinker when they come back to it. "If you're sick or recovering from an illness that left you caffeine-free for a few days, it's a good idea to ease back into your coffee habit," Nussbaum says. Of course, whenever you're sick, it's important to hydrate as much as possible. Tips to Stay Hydrated Everyone reacts to caffeine differently and has different hydration needs based on their size, age, and how much they exercise. Two cups of coffee may have little impact on one person, while another will feel more heightened effects. And not all cups of coffee have equal levels of caffeine. If you're noticing a pattern of adverse reactions, it's best to decrease the amount of coffee you're sipping. Also, don't mistake caffeine tolerance as a free pass not to hydrate in general. While coffee itself isn't too dehydrating, frequent coffee drinkers should still hydrate in other ways. Dietitians suggest enjoying coffee after hydrating with a glass of water and having some food. Due to the high acidity in most coffees, consuming coffee on an empty stomach may lead to stomach discomfort. Additionally, experts recommend maintaining proper hydration throughout the day after coffee consumption. "Don't let your caffeine intake impair your intake of straight fluids like water," Nussbaum says. Coffee may not dehydrate you detrimentally, and it can even count toward your daily hydration—but it's still imperative to drink enough water (and other more hydrating drinks) throughout the day. If you're prone to experiencing caffeine's diuretic effects, refrain from caffeine consumption four to six hours before bedtime. This step can help reduce the chances of waking up dehydrated in the morning, as caffeine close to bedtime may lead to increased urination. As for the decaf coffee drinker? Even decaf has trace amounts of caffeine, but it certainly has less of a diuretic effect than regular coffee. The biggest takeaway is the see how you feel. "The easiest way is to pay attention to what your body feels like when you drink coffee: its impact on your sleep and the number of times you're going to the bathroom," says Nussbaum. Frequently Asked Questions What is a diuretic? A diuretic is a substance that expels salt and excess fluid out of the body, leading to increased urination. Caffeine is a diuretic because it enhances blood flow to the kidneys, which prompts the organ to release fluid through urine. What type of coffee has the most caffeine? The type of coffee with the highest caffeine content varies based on brewing method and bean type. Typically, a single shot of espresso contains around 63 mg of caffeine, while an 8-ounce cup of brewed coffee has around 70-140 mg of caffeine depending on the roast of the beans. Meanwhile, a 16 ounce serving of cold brew usually packs around 200 mg of caffeine, making it the coffee with the highest caffeine concentration. Can coffee cause electrolyte imbalance? Research indicates that drinking coffee does not cause electrolyte imbalance. As long as you stay hydrated throughout the day, coffee consumption does not negatively impact exercise performance or overall health. I Tried CBD in My Coffee—and I'm Still Not Sure What I Felt Was this page helpful? Thanks for your feedback! Tell us why! Other Submit Sources Real Simple is committed to using high-quality, reputable sources, including peer-reviewed studies, to support the facts in our articles. Read our editorial guidelines to learn more about how we fact check our content for accuracy. National Coffee Association, "NCA releases atlas of American coffee." Killer SC, Blannin AK, Jeukendrup AE. "No evidence of dehydration with moderate daily coffee intake: a counterbalanced cross-over study in a free-living population." PLoS One. 2014;9(1):e84154. doi:10.1371/journal.pone.0084154 Neuhäuser-Berthold null, Beine S, Verwied SC, Lührmann PM. Coffee consumption and total body water homeostasis as measured by fluid balance and bioelectrical impedance analysis. Ann Nutr Metab. Maughan RJ, Griffin J. "Caffeine ingestion and fluid balance: a review." J Hum Nutr Diet. U.S. Department of Agriculture. "Nutrients in beverages, coffee, brewed, espresso, restaurant-prepared." FoodData Central. U.S. Department of Agriculture. "Nutrients in beverages, coffee, brewed, prepared with tap water." FoodData Central. Armstrong LE. "Caffeine, body fluid-electrolyte balance, and exercise performance." Int J Sport Nutr Exerc Metab.