Plain Water—The Surprising Runner-Up
Here’s something that might shock you: plain water isn’t actually the most hydrating beverage around, according to recent scientific research from Scotland’s St. Andrews University. While water does an excellent job at quickly entering your bloodstream, beverages with a little bit of sugar, fat or protein do an even better job of keeping us hydrated for longer. Think of water like a sprinter—fast to act but doesn’t stick around long enough for the marathon.
Plain water is still the best way to hydrate, no second guessing necessary, and it’s the foundation of all proper hydration. Water is calorie-free, easily accessible and essential for every bodily function, helping regulate body temperature, supporting digestion and keeping your skin healthy. It’s like having a reliable friend who’s always there when you need them most.
Milk—The Unexpected Hydration Champion
Skimmed milk, full-fat milk, and oral rehydration solutions were all more hydrating than water according to groundbreaking research published in The American Journal of Clinical Nutrition. Milk was found to be even more hydrating than plain water because it contains the sugar lactose, some protein and some fat, which slow the emptying of the stomach, keeping fluids in the body longer, plus sodium, which helps the body retain water.
Scientists discovered this by testing people’s urine output over four hours after drinking different beverages. In the study of 72 people, milk drinkers produced about 37 ounces of urine over four hours while water drinkers produced 47 ounces. That ten-ounce difference might seem small, but it represents significantly better fluid retention.
Oral Rehydration Solutions—Medical-Grade Hydration
Oral rehydration solutions like Dioralyte are designed for medical use for cases of dehydration and contain small amounts of sugar, sodium, and potassium, creating a balance that enhances water retention in the body. These aren’t just fancy sports drinks with marketing budgets—they’re scientifically formulated solutions that hospitals use to treat severe dehydration.
Oral rehydration solutions like DripDrop were developed by doctors on missions to defeat life-threatening dehydration, and studies show they are the most effective for dehydration. Solutions with sodium content of at least 40 mmol/L support exercise-induced sodium sweat losses better than lower sodium formulations, and solutions with lower osmolality optimize intestinal water uptake. Think of these as the Navy SEALs of the hydration world.
Coconut Water—Nature’s Sports Drink
Coconut water boasts 95 percent water content, which is better than fruit juice, and it’s typically healthier than juices and sports drinks when it comes to sugar content and added ingredients. Coconut water is refreshing and packed with potassium, making it an excellent natural alternative to artificial sports drinks.
Rich in electrolytes like potassium, sodium and magnesium, coconut water is a natural hydrator that helps replenish lost fluids and minerals, making it an excellent post-workout drink. However, you should watch out for versions with added sugar. It’s like getting all the benefits of a sports drink without the laboratory-created ingredients.
Sports Drinks—When Timing Matters
Sports drinks like Gatorade actually are onto something—the electrolytes, a science-y word for salts, in sports drinks can make hydration more effective. But here’s the catch: they’re really only beneficial during intense, prolonged exercise when you’re sweating heavily. If you do a lot of intense exercise, consider a post-workout beverage that contains some carbohydrates, sodium, and other electrolytes to replace water you lose through sweat.
The key is understanding when to reach for them. High-quality studies that are not funded by industry players indicate that sports drinks are only as effective as plain water when it comes to hydration. For the average person doing moderate exercise, you’re probably better off sticking with water or one of the other options on this list.
Herbal Teas—The Gentle Hydrators
Herbal teas, such as chamomile or peppermint, are hydrating and soothing, helping with digestion, reducing stress and providing gentle flavor without the risk of dehydration from caffeine. Unlike their caffeinated cousins, herbal teas won’t work against your hydration goals.
Herbal teas are caffeine-free and a great alternative to coffee and caffeinated tea, which have diuretic effects, and many herbal teas have health-promoting properties that can help lower inflammation, support heart health, or promote relaxation. It’s like getting a warm hug in a mug while staying perfectly hydrated.
Infused Water—Flavor Without the Consequences
If it’s hard for you to drink plain water all day, infusing your water with fruit is a healthy way to add flavor without adding sugar, with favorite combinations including lime and basil, cucumber with mint. Adding fruits, herbs or vegetables to your water can enhance the flavor and provide additional nutrients, like vitamins and antioxidants, making hydration more enjoyable.
This approach gives you all the hydrating benefits of water while making it interesting enough that you’ll actually want to drink it throughout the day. Sparkling water and infused waters made with fruits and herbs are great ways to mix it up while staying hydrated. It’s basically water that went to charm school.
Alcohol—The Hydration Saboteur
Now let’s talk about what to avoid. Alcoholic beverages, including beer, wine, and liquor, can change your body’s fluid balance by reducing the secretion of vasopressin, a hormone involved in the regulation of urine output, and could cause dehydration if consumed in large amounts. As a general rule of thumb, the higher the alcohol content, the more dehydrating your drink is, with any alcoholic drink over 10 percent alcohol strength being a dehydrator.
Alcohol is a diuretic, which means it causes you to urinate more by inhibiting you from reabsorbing water, and the higher the alcohol content a drink has, the greater the diuretic and dehydration effect. Dark drinks such as red wine, whiskey, or brandy contain congeners—chemicals that ensure the alcohol stays in your body longer, dehydrating you more than clear drinks.
High-Caffeine Beverages—The Double-Edged Sword
At doses above 300 mg of caffeine—around 3 or 4 cups—the risk of fluid loss increases, particularly for those unaccustomed to caffeine, though the effect is short-lived and mild. A small study found that consuming 537 mg of caffeine, or about 6 cups of coffee, significantly increased urine production, and participants who consumed over 500 milligrams of caffeine daily showed disruptions in fluid balance.
The good news? A regular coffee would be pretty much as hydrating as water for most people. Coffee and tea also count in your hydration tally, as many used to believe that they were dehydrating, but that myth has been debunked since the diuretic effect does not offset hydration. Moderation is key—think of caffeine like a good friend who becomes annoying when they overstay their welcome.
Energy Drinks—The Hydration Destroyers
Energy drinks can increase the risk of dehydration, possibly because of their caffeine content, and may contain a combination of dehydrating ingredients, generally containing high levels of caffeine and sugar and other added ingredients that stimulate the kidneys. Certain types of energy drinks contain other ingredients that could contribute to dehydration, like taurine, which is a compound with diuretic effects.
Energy drinks are like that friend who promises to help you move but then calls in sick—they seem helpful but often make things worse. Drinking caffeinated beverages such as energy drinks won’t have a hydrating effect and may contribute to dehydration, as caffeine stimulates urine production and can interfere with water reabsorption.
Soft Drinks and Sodas—The Sweet Deceivers
Soft drinks often contain caffeine, which is a culprit for dehydration; tons of sugar and sodium; and it’s bad for your bones and teeth, too. Soda often contains caffeine and high amounts of sugars, and while the consumption of a cold soda may feel refreshing at first, it likely will not satisfy a person’s thirst in the long run, as the sensation of a cool, carbonated beverage makes people think it quenches thirst better, leading to drinking less additional liquid.
Sugar has dehydrating effects because it changes the osmotic pressure within the digestive tract, which causes fluids to be drawn from the body into the intestines, contributing to water loss and dehydration. It’s like paying someone to steal your wallet—you think you’re getting something good, but you’re actually losing something valuable.
High-Sugar Fruit Juices—The Healthy Imposters
Fruit juice contains about 85 percent water, which makes it super hydrating when you’re picking 100 percent fruit juice, but you should be mindful of the sugar content, as juices can be packed with added sugars, which can inhibit hydration, so if you’re drinking a lot of fruit juice, water it down. Beverages with more concentrated sugars, such as fruit juices, are not necessarily as hydrating as their lower-sugar cousins, as their high concentration of sugars gets diluted during osmosis, which pulls water from the body into the small intestine.
The natural sugars in fruit juice can work against you if you’re not careful. It turns out that too much sugar can become a drawback when it comes to hydration. Think of high-sugar juices like a beautiful sports car with sugar in the gas tank—looks great but won’t get you where you need to go.
Hot Chocolate and Sugary Hot Beverages—The Winter Traitors
One cup of hot chocolate contains more sugar and calories than a can of soda, dehydrating your system, though in the winter, people tend to eat more soups and stews, which offer hydration, so having the occasional hot cocoa isn’t going to hurt. These seemingly comforting beverages can actually work against your hydration goals when consumed regularly.
The high sugar content in these drinks creates the same osmotic problems as sodas and fruit juices. Consumers say that staying hydrated is the top action they take to improve their health, and hydration is the most desired benefit and the top reason consumers give for buying a particular food or beverage. Don’t let these cozy drinks fool you into thinking they’re helping when they’re actually hindering your hydration efforts.
The Science Behind Smart Hydration Choices
It should be possible to assign a beverage hydration index to each drink that will define the hydration response, similar to how the glycemic index defines blood glucose response, with the cumulative volume of urine passed over a fixed period being the area under the curve for renal water excretion. This scientific approach helps us understand why some drinks work better than others.
While staying hydrated is important for keeping joints lubricated, preventing infections, and carrying nutrients to cells, in most situations people don’t need to worry too much about how hydrating their beverages are, but for athletes training seriously in warm conditions or those whose cognitive function may be impacted by working long hours without beverage breaks, hydration becomes critical. If you’re thirsty, your body will tell you to drink more, but making smart choices about what you drink can make all the difference in how you feel.
Understanding hydration isn’t just about drinking more—it’s about drinking smarter. Your body is constantly working to maintain the perfect fluid balance, and the beverages you choose can either support or sabotage that effort. The next time you reach for a drink, remember that not all liquids are created equal when it comes to keeping you properly hydrated.
