Scientists Reveal the Top 5 Most Hydrating Drinks—and Water Isn’t Even in the Top Three

18 December 2025

Is water overrated? For centuries, it’s reigned as the ultimate hydration hero. But according to a recent revelation from scientists, maybe we’ve been cheering for the wrong liquid all along—water isn’t even in the top three when it comes to hydrating power! Let’s dive straight into the facts, because it just got splashy in the world of hydration rankings.

Water: Ubiquitous, Essential… But Not #1?

Before anyone starts up an angry group chat in defense of aqua, let’s be clear: water is absolutely vital for nearly every living being on this planet. Life literally depends on it. But is it really the champion of hydration, or have we been giving it a little too much credit?

At first glance, the answer seems painfully obvious. When thirsty, humans reach for water instinctively. But let’s dig deeper. Chemically speaking, pure water (dihydrogen monoxide, if you’re trying to impress at trivia night) is H₂O. But that’s distilled water—the kind you’re not usually sipping at lunch. Tap and bottled waters come with a healthy serving of minerals. And guess what? Those minerals matter, especially when it comes to keeping your body’s electrolyte balance in check.

Mineral water is more aligned with what most of our bodies expect and need. Regularly drinking only distilled water, as pure as it may sound, can actually mess with your electrolyte balance over time. Electrolytes like magnesium, potassium, and calcium are crucial; they stick to water, keep your body’s chemistry humming, and help balance its fluids.

The Electrolyte Equation

So, if pure water isn’t optimal by itself, what is? To truly quench the body, scientists say finding liquids packed with electrolytes is key. Enter the humble oral rehydration solution—yes, those little sachets often handed to babies after a bout of stomach trouble. These powders add salts and nutrients to water, helping to slow down the loss of fluids, electrolytes, and other important compounds, meaning you stay hydrated more effectively.

Selection can be daunting, though. The beverage aisle is an endless parade of drinks: sweet, fruity, fizzy, or fortified—which hydrates best? Most product labels leave you clueless. That’s where the team at the University of St Andrews School of Medicine stepped in. Fed up with the mystery, they conducted a thorough study to identify, once and for all, which drinks truly top the hydration charts.

The Study Behind the Shocking Top 5

The researchers didn’t just chug and judge. They compared beverages based on how quickly and how long they hydrated the body, according to the Beverage Hydration Index (BHI). Curious findings emerged: drinks with some lactose, proteins, and even a little fat can slow down how quickly fluids leave the body, helping you stay hydrated for longer stretches.

Skim milk: Topping the list with a BHI of 99%. It’s the unexpected hydration MVP!
Oral rehydration solution: Also scoring 99%, thanks to its mix of mineral salts and compounds that actively maintain hydration.
Whole milk: Not far behind—demonstrating that a touch of fat helps fluids stick around.
Orange juice: Just edges past water, clocking in at 95% BHI.
Water: Still a classic, just not the all-time champ here.

The research surprised many. While the difference between water and other beverages might seem minor, it’s actually enough to make a real difference for some.

Should You Swap Your Water Bottle for Milk?

Before you rush to fill your gym bottle with orange juice or start mixing up oral rehydration powder for everyday sipping, the scientists caution: their study didn’t look at the long-term effects of surviving exclusively on these “winning” drinks instead of water. For the vast majority, water remains a safe, solid, and simple choice.

However, these findings could be especially helpful for certain groups—like the elderly, infants, or people with disabilities who may struggle to drink large amounts of fluids. For them, maximizing hydration from every sip can be crucial.

So, while water’s not leaving your side as a hydration essential, maybe it deserves to share the spotlight. Turns out, sometimes it’s the quiet achievers (here’s looking at you, skim milk) who keep us running strongest. And if nothing else, you now have the perfect fact to dazzle the next time someone reminds you to “just drink more water.” Cheers to staying hydrated—whichever way you pour it!