Hydration Isn't Just About What Counts as Water
Apparently, we need to talk about hydration.
More specifically, we need to talk about the not-so-internet-friendly argument that says caffeine isn't dehydrating, herbal diuretics aren't dehydrating, and therefore anyone suggesting you shouldn't rely on caffeinated or strongly diuretic beverages for 100% of your daily fluid intake is spreading outdated misinformation.
There is a grain of truth in that argument.
There is also a rather impressive amount of nuance that tends to disappear somewhere between reading the abstract and confidently announcing that science has "debunked" something.
And since I apparently enjoy making my life more difficult, let's talk about it.
First: Is caffeine dehydrating?
Yes...but also no....but not exactly.
Caffeine has a diuretic effect. That's not a myth. Caffeine acts on the kidneys and can increase urinary output, particularly at higher doses and in people who aren't accustomed to caffeine. But here's where the nuance matters. Research examining caffeine and hydration has found that moderate amounts of caffeine consumed as part of normal beverage consumption still contribute to total fluid intake. Habitual caffeine consumers also develop tolerance to some of caffeine's diuretic effects. It's important to note that tolerance does not equate to being healthy.
A review of the research found that acute doses in the neighborhood of 250–300 mg or more can increase urine output in people who haven't consumed caffeine for a period of time, while the effect is substantially reduced in regular coffee and tea drinkers.
Another controlled study found that caffeine concentrations up to 400 mg/L did not significantly alter urine output or net fluid balance in healthy, already-hydrated adults. In that study, caffeine itself wasn't what determined how well the beverage was retained.
So, yes:
Your coffee counts toward your fluid intake....if it is in MODERATE amounts with OTHER
BEVERAGE CONSUMPTION.
No, you don't need to drink an additional glass of water for every cup of coffee because your kidneys send the entire cup directly to the urinary tract. But that doesn't mean caffeine suddenly stopped being pharmacologically active.
Those are two different statements.
And this distinction is precisely where reading to comprehend instead of regurgitating becomes critical.
Now let's talk about "excessive"
This is where the word moderation apparently gets people confused.
Moderation doesn't mean:
"I can consume as much as I want because technically it isn't dehydrating."
It means consuming something in an amount that is reasonable within the context of your overall diet, health, physiology, medications, environment, and activity level.
For healthy adults, a commonly cited level supported by a large systematic review is up to about 400 mg of caffeine per day, as an intake generally not associated with overt adverse effects in the healthy adult population. That is a ceiling used for safety assessment, not a recommendation that everyone should consume 400 mg of caffeine every day.
Research has also found dose-dependent effects of caffeine on anxiety, with higher doses producing substantially greater effects in the studies included in a recent meta-analysis. A 2025 meta-analysis of controlled trials also found that caffeine reduced total sleep time and sleep efficiency and increased the time it took participants to fall asleep. While not technically related to dehydration specifically, this illustrates how the other impacts of specific substances can and do impact the overall system. This is exacerbated when dehydration is present.
So if your definition of "moderate" is:
four energy drinks, three coffees, a pre-workout, and an herbal stimulant tea because technically they all contain water...
we may want to revisit the definition.
Hydration is not the only thing your body needs you to consider.
And now for the herbs
Here's where this whole conversation started over on social media (yes, I know, that was my first problem...)
Herbal infusions can absolutely contribute to your daily fluid intake. They can even help increase hydration.
The National Academies' Dietary Reference Intakes specifically define total water intake as coming from drinking water, other beverages, and the water contained in food (watermelon and cucumber are two of my favorite hydrating foods).
So if you make yourself a big mug of lemon balm tea? Congratulations. You're hydrating. It's not a diuretic, so it isn't going to cause water to be pulled from your body.
If you make peppermint tea? Chamomile? Alfalfa? Ginger? Yep...you're hydrating your body.
The plant doesn't magically cancel out the H₂O.
However...I know! I know! Nuance drives people crazy, but it is the crux of what I live for.
Some herbs have diuretic activity. Just like caffeine.
And just like caffeine, dose and duration matter. Several herbal diuretics have been identified, including fennel, hibiscus, parsley, horsetail, and several species of Sambucus. As with most herbal studies, the evidence base for many herbal diuretics remains limited, and additional research is needed. Sadly, this is the world we live in. But we do know that there are multiple mechanisms through which plant compounds can influence renal water and electrolyte handling.
That distinction matters.
So should you avoid diuretic herbs?
No. That's not what I'm saying either. Diuretic herbs can have legitimate traditional and therapeutic uses.
There are reasons someone might intentionally choose a plant with diuretic activity. But using a diuretic herb therapeutically is different from choosing a strong, diuretic infusion as the primary beverage you consume all day while assuming that the fact that it contains water makes everything else irrelevant.
Context matters. Dose matters. Frequency matters. And, apparently, reading the methods section matters too.
Wild concept, I know.
What does adequate hydration actually look like?
Your body doesn't require you to drink some magical number of ounces of plain water while simultaneously pretending that everything else you've consumed doesn't exist.
Total water comes from water, other beverages, and food. Your needs also vary according to body size, activity, climate, illness, sweating, diet, and other individual factors.
This is especially important if you live somewhere hot. Live in the desert....during the summer when it's hotter than satan's ball sack...
I don't live in the desert. I don't know what you're talking about. Anywho...
If you're sweating your ass off in the Arizona heat, your fluid and electrolyte needs aren't necessarily the same as someone sitting in a climate-controlled office in Maine. The body regulates hydration through thirst, the kidneys, hormones, and changes in urinary concentration and volume. There isn't one magic number that guarantees perfect hydration for every human being every day.
Which brings us back to moderation. More appropriately, balance. That means your overall fluid intake comes from a variety of sources, rather than trying to make one beverage or one category of beverage do all the work. And that you aren't only consuming beverages that are designed to move fluid OUT of your cells.
So what can you drink if you really hate water?
If you want to increase your fluid intake without making plain water your entire personality, herbal infusions are a fantastic option. So are fruit infusions. I personally can't stand them, but not everything is about me.
Some herbs I particularly like for simple, non-diuretic-focused infusions include:
Bright, mild, and ridiculously easy to drink either hot or cold. It's also fantastic for helping support the nervous system.
Peppermint (Mentha × piperita)
Refreshing, especially iced, and a great after-meal infusion for people who enjoy something cooling and aromatic.
Soft, floral, and naturally caffeine-free. It also helps to reduce inflammation in the body and makes for a great nightcap.
Ginger makes an excellent infusion on its own or blended with other herbs. You can drink it hot, pour it over ice, or add citrus for something that feels much more like an actual beverage than "I'm forcing myself to drink water because apparently adulthood is a hydration challenge." Always make sure to use fresh, though, because the powdered stuff has a completely different chemical makeup.
The bottom line
Caffeine isn't the hydration boogeyman we've sometimes made it out to be. Moderate caffeine consumption does contribute to your daily fluid intake...IF YOU ARE HEALTHY.
But higher caffeine doses produce diuretic effects, and caffeine can have other physiological effects that have absolutely nothing to do with whether the beverage contains water.
Likewise, a cup of diuretic herbal tea still contains water and therefore contributes to your total fluid intake. But if you're consuming large quantities of strongly diuretic herbs, you're also intentionally encouraging your kidneys to increase urinary excretion. That's worth considering when you're looking at your overall hydration strategy.
This isn't an argument for fear. It's an argument for context. And when people are asking for context, giving that to them is a beautiful thing. Not making blanket statements.
You don't need to panic about your morning coffee. You don't need to stop drinking tea. You don't need to carry a gallon jug of plain water everywhere you go. And you absolutely don't need to believe that every beverage containing caffeine or a diuretic herb somehow "doesn't count."
But there's also no scientific basis for taking the very specific finding that
moderate caffeinated beverages can contribute to hydration
and stretching it into
therefore the composition, dose, frequency, and physiological effects of what I drink don't matter.
That's not how science works. And honestly, it's not how reading works either. But it absolutely is how social media works. Insert eye-roll.
Hydration isn't about finding the one beverage that technically counts. It's about giving your body enough total water and electrolytes to support the work it's doing—and understanding that different things you consume can influence that balance in different ways.
Drink the coffee. Drink the tea.
But also drink the damn water. Or infusions that add to your hydration in measurable ways. Either way, just know what you're actually consuming.
With a modicum of sass,
Maughan, R. J., & Griffin, J. (2003). Caffeine ingestion and fluid balance: a review. Journal of Human Nutrition and Dietetics, 16(6), 411–420. DOI: 10.1046/j.1365-277X.2003.00477.x
Killer, S. C., Blannin, A. K., & Jeukendrup, A. E. (2014). No Evidence of Dehydration with Moderate Daily Coffee Intake: A Counterbalanced Cross-Over Study in a Free-Living Population. PLOS ONE, 9(1), e84154. DOI: 10.1371/journal.pone.0084154
Institute of Medicine. (2005). Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. National Academies Press. DOI: 10.17226/10925
EFSA Panel on Dietetic Products, Nutrition and Allergies. (2015). Scientific Opinion on the safety of caffeine. EFSA Journal, 13(5), 4102. DOI: 10.2903/j.efsa.2015.4102
Liu, C., et al. (2024). Caffeine intake and anxiety: a meta-analysis. Frontiers in Psychology, 15. DOI: 10.3389/fpsyg.2024.1270246
Yarnell, E., & Touwaide, A. (2019). Accuracy of Dioscorides' De materia medica (First Century C.E.), Regarding Diuretic Activity of Plants. Journal of Alternative and Complementary Medicine, 25(1), 107–120. DOI: 10.1089/acm.2018.0251
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