The Most Hydrating Drinks, Ranked by Science

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Water isn’t the top of the list. A few everyday drinks keep fluid in your body a little longer, and most of the rest tie it rather than fall behind. Here’s the leaderboard, and what each tier means for what you actually reach for.

Which drinks are the most hydrating?

Researchers ranked thirteen common drinks by how much fluid each kept in the body over four hours versus plain water, in a 2016 trial (Maughan et al.). Four landed modestly ahead. Here’s the full board.

Not one of the thirteen drinks in this 2016 panel, from cola to lager, scored below plain water.

It’s one trial in 72 men over a few hours, so read the board as the best available guide, not a fixed law.

What does the top tier mean for you?

Skim milk, oral rehydration solution and whole milk sit at the top because they carry protein, fat and electrolytes that slow how fast the fluid leaves you. In practice, a glass of milk with breakfast is doing a little more hydration work than the same glass of water. That’s a bonus if you were drinking it anyway, not a reason to swap your water for a carton.

Oral rehydration solution earns its place the same way, which is exactly why it’s the thing to reach for after a stomach bug or a heavy sweat, and overkill on a normal desk day. Orange juice’s raw 1.39 cleared water too, but its edge mostly vanishes once you correct for the water the juice already contains (P=0.11), so treat it as a tie, not a top-tier hydrator.

Where do coffee, tea and soda land?

Right alongside water, and that’s the useful part. Coffee, tea, cola, diet cola, sparkling water and a sports drink all scored statistically level with plain water. Level is not a loss.

Your morning coffee and afternoon tea count toward your fluid for the day exactly like a glass of water, caffeine and all (more on that in our coffee piece). Sparkling water is the same deal as still: the bubbles change nothing about how it hydrates you. A sports drink sat in that tied group too, worth remembering the next time the label promises more, since on a normal desk day it hydrates you no better than the tap. If you like these drinks, keep drinking them, and stop mentally scoring them at zero.

Is there an exception?

One. The single alcoholic drink in the trial, lager, tied water rather than trailing it, so even beer isn’t the villain the ranking might lead you to expect.

Brim treats alcohol more strictly anyway. It’s the one category we credit below zero (Premium), a deliberate nudge rather than a lab reading. Nobody finishes a heavy night better hydrated than they started, so the app leans cautious. If you’re tracking a night out, the water between rounds is what actually moves your number.

How should you count your drinks?

A tracker that scores everything except water at zero is throwing away real data. One that scores milk the same as water hides a real, if small, difference the other way.

Our honest answer: credit each drink by roughly where the evidence puts it. That’s what we built Brim to do. Brim credits every non-water drink by a version of this ranking (Premium): milk, coffee, tea, juice and soda each at their own percentage of a glass of water, and alcohol below zero. Free logging covers water only; the percentages themselves show for every user, free or not, in the BHI Hydration Index Lookup.

Our numbers aren’t a straight copy of the trial. Milk is credited at 130%, below its raw figure, because a glass also carries natural sugar the hydration score ignores. Coffee caps at 90% at its gentlest. In our experience, real-world tracking should stay a little more conservative than a single lab morning.

Key takeaways