Monday Mythbuster #41: Decaf Coffee Dehydrates You

You might have heard the rumor that your cherished cup of decaf coffee can dehydrate you.

This idea stems from the fact that caffeine, present even in decaf coffee (though in considerably lesser amounts), is a diuretic.

This means that it encourages the kidneys to excrete more water.

But here's the truth: the amount of water that coffee makes you lose is significantly less than the amount of water you take in by drinking it.

In other words, rather than dehydrating you, having a cup of coffee can contribute to your daily water intake.

Regular Vs. Decaf: A Hydration Comparison

Myth: Decaf Hydrates You Less Than Regular Coffee

This myth is based on the deduction that since decaf contains less caffeine than regular coffee, it must have less of a diuretic effect – and hence, less of a hydrating effect.

However, according to credible sources like Healthline, this is a misconception.

Regardless of its lower caffeine content, decaf coffee's net hydration effects are nearly on par with plain water.

Decaf As A Water Substitute

Myth: Decaf is As Good As Water For Hydration

While it can be tempting to believe that if decaf doesn't cause dehydration, it can replace water as a primary source of hydration, it's essential to set the facts straight.

According to Precision Fuel & Hydration, drinking decaf coffee is not equivalent to drinking water.

While decaf hydration levels are surprisingly good, mainly due to its lower caffeine, it shouldn't fully replace other sources of hydration, including good old water.

Dehydration Symptoms: What To Look For

Myth: Drinking Coffee Must Be Making Me Dehydrated Because I Have These Symptoms

If you are feeling thirsty, experiencing a dry mouth or tongue, or noticing darker urine, it's easy to think it's due to the coffee you drink.

But remember, coffee, including decaf, isn't a significant cause of dehydration.

These symptoms might be indicative of actual dehydration, in which case you should consider increasing your fluid intake.

Optimal Water Intake: What's The Ideal Quantity

Myth: Eight Cups of Water Is The Universal Requirement

Again, a common myth busted.

Various factors influence water intake requirements such as age, body weight, height, level of physical activity, and more.

While sipping on a cup of coffee now and then is harmless, make sure to keep yourself hydrated with plain water too.

Conclusion: Debunking The Coffee Dehydration Myth

The popular myth that regular or decaf coffee leads to dehydration has been debunked!

The bottom line is, while coffee acts as a mild diuretic, it does not cause dehydration.

Feel free to enjoy your daily cup (or two...or three) and ensure you are having a sufficient intake of water and other hydrating beverages.

If you find yourself struggling with hydration, don't blame your coffee. Instead, consult with your healthcare provider to pinpoint the cause and find a solution.

Stay hydrated my friend,


Founder & CEO


Oh!mino is a sports performance brand under Oh!Nutrition, specializing in science-backed nutritional products. Founded in 2008, our California-based parent company focuses on innovative, scientifically validated supplements. Our flagship offering, Oh!mino Muscle Synthesis Activator, sets a new standard in performance supplements. Experience the difference with our patented essential amino acid products, designed to elevate your performance. Learn more on our website.

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