Do Coffee And Tea Dehydrate You? (The Facts About Caffeine)

A woman drinking coffee wondering if it will dehydrate her.

It is apparent that our society has grown with the notion that the consumption of tea and coffee causes dehydration to the body. However, there has been little research carried out to support this claim. Research shows that consuming healthy amounts of coffee and tea will not dehydrate you.

If you are reading this article, there’s a good chance that you drink tea and coffee regularly and you are interested in how they affect the hydration levels in your body. 

In this article, we will dive a little deeper into the effects that coffee, tea, as well as decaffeinated coffee and herbal tea have on your body’s hydration levels. More specifically, the topics covered in this article include (click on one of the topics below to scroll to that section):

What Is Dehydration?

You become dehydrated when a significant amount of body fluids are lost. As a result of your body losing these fluids, your normal body functions can be impaired. In other words, dehydration occurs when your body does not have enough water required to carry out its regular functions.

Every day your body naturally loses fluids through various means such as sweating, breathing, and urinating.

The fluid that your body regularly loses can be replenished by drinking water or other healthy liquids, as well as eating foods that contain a high percentage of water.

What Is Caffeine? (Why Is It So Popular?)

Caffeine is one of the most commonly used natural stimulants in the world. It is mostly found in tea leaves and also usually found in beans, kola nuts, and cocoa plants. Around 90 to 93% of individuals around the world consume caffeine in one form or another.

Natural tea leaves contain more caffeine than raw coffee beans. However, by the time it reaches your mug, a cup of coffee typically contains more caffeine than a cup of tea.

This is because coffee is usually brewed with hotter water, which helps to extract more caffeine from the beans. Furthermore, there are typically more coffee beans used to brew one cup of coffee than there are tea leaves used for one cup of tea.

Individuals consume caffeine because it is considered to be psychoactive as it stimulates the brain and central nervous system within 10 to 45 minutes of ingestion. As a result, it makes you more alert as well as it helps to boost your energy.

It can take up to six hours for caffeine to be completely broken down by your body and cleared out from your system.

Debunking The Myth: Why So Many People Think Caffeine Dehydrates You?

The notion that coffee and tea cause dehydration to the body is based on a 1928 study involving just three men. The men were studied over the course of two winters.

The men drank a variety of drinks that contained caffeine. Initially, the men were required to drink four cups of coffee a day, other times they drank mainly tea and sometimes, they drank water laced with pure caffeine.

At regular intervals, the volume of their urine was measured to determine how much fluid their bodies were loosing. As a result of the study, researchers were able to conclude that when the men consumed caffeinated drinks, the volume of their urine increased.

Since then, the notion began to spread that beverages containing caffeine could, because of the diuretic effects, increase the amount of fluid your body loses and lead to dehydration.

Although tea and coffee contain different substances, they both contain caffeine which is the point of focus for most research.

Can Coffee Dehydrate You?

A cup of coffee on a table, can coffee dehydrate you?
A Cup Of Coffee – Can It Dehydrate You?

It is often suggested that coffee causes dehydration and so, it’s consumption should be completely avoided or reduced significantly in order to maintain fluid balance in the body.

However, this is untrue because although coffee is diuretic, the excess urination you experience when you consume coffee doesn’t lead to dehydration unless you fail to drink more fluids.

Research carried out at the University of Birmingham in the U.K intending to study the fluid levels of 50 men who had a habit of consuming about three to six cups of coffee each day. The study indicated that moderate consumption of coffee provided similar hydrating qualities as water.

Therefore the next time you find yourself contemplating whether or not to take that hot cup of coffee due to fear of dehydration, do not hesitate to drink it.

Does Tea Dehydrate You?

Tea is one of the most popular and widely consumed beverages in the world. Just like coffee, most people hold a popular opinion that tea dehydrates you because of its caffeine content.

In a rare study where people drank nothing but tea for the duration of the trial, there appeared to be no difference between the hydration levels of individuals who drank the same quantity of boiled water.

This study disproves the idea that drinking tea can dehydrate your body as a result of its caffeine content. Consequently, one can argue that tea can provide similar hydrational value to your body as water does.

Can Decaf Coffee Dehydrate You?

No, decaf coffee by itself cannot dehydrate you.

The word decaf, which is short for decaffeinated, indicates the removal of caffeine from coffee beans or tea leaves.

Decaf is not completely free of caffeine but at least 97% of its caffeine has been removed. Studies have shown that, on average, a cup of regular coffee can contain anywhere between 70 to 140 mg of caffeine. However, each cup of decaf coffee can contain between 0 and 7 mg of caffeine.

This, of course, depends on several factors including the preparation method, coffee type, and cup size.

Many individuals enjoy drinking a cup of coffee in the morning to kickstart their day and even at regular intervals throughout the day. However, for a variety of different reasons, several individuals try to limit their caffeine intake.

So instead they opt for decaf coffee. It as an excellent alternative as it still provides a full taste and a similar amount of antioxidants as regular coffee.

Are Coffee And Tea Diuretics?

Yes, they are! (well, except for decaf coffee, it does not have a diuretic effect on your body).

A substance that is a diuretic refers to anything that promotes the formation of urine by the kidneys. Diuretics cause you to lose water from your body through various means. As provided by MedicineNet, some of these means include:

  • Inhibiting the kidney’s ability to reabsorb sodium, hence enhancing the loss of sodium and water in the urine
  • Preventing the exchange of sodium for potassium, thus resulting in the excretion of sodium and a moderate amount of potassium.
  • Enhancing the excretion of both sodium and chloride in the urine so that water is excreted with them.

Your consumption of coffee can make any of these to occur thereby causing your body to lose water. But there’s no need to fret, just because a substance is classified as diuretic does not mean it can cause dehydration by itself.

Studies show it takes as much as 360 milligrams of caffeine to act as a diuretic, and a cup of regular coffee can have anywhere from 95 to 200 milligrams of caffeine depending on the brew. So, you see that it will take at least 2 cups of regular coffee to have diuretic effects on your body.

Does Drinking Coffee And Tea Help You Stay Hydrated?

Yes, drinking coffee and tea will help you stay hydrated. Although it shouldn’t be your only source of hydration.

Dr. Daniel Vigil, an associate professor at the University of California Los Angeles, explains when you drink coffee or tea, you are still consuming liquids that your body will absorb and use to help your hydration levels.

As he states, “even though caffeine is a mild diuretic, you won’t lose more fluid through urine than you take in by drinking a caffeinated beverage because your body can absorb as much fluid as it needs and expel the rest.”

The Benefits Of Drinking Coffee And Tea

It can be said that after water, coffee and tea are some of the most often enjoyed beverages consumed across the world.

Studies show that 1.6 billion cups of coffee and around twice as many cups of tea are consumed daily. There is a strong chance that you already enjoy at least one of these two popular beverages.

Have you ever thought about the benefits of consuming your favorite tea or coffee? Well, whether you are a coffee or tea drinker, or even both, you enjoy some of the same benefits. In addition to helping you stay hydrated, coffee and tea can help benefit you by:

1. Polyphenol Contained In Coffee And Tea Has Antioxidant Properties

These properties are believed to help prevent inflammatory illnesses. Furthermore, polyphenol helps boost insulin sensitivity and also slows down the rate in which your body absorbs and digests sugar.

A new study led by Harvard School of Public Health (HSPH) researchers showed that population who increased the amount of coffee they drank each day by more than one cup over four years had an 11% lower risk for type 2 diabetes than those who made no changes to their coffee consumption.

Properties of polyphenol have also been shown to help reduce the risk of strokes and cardiovascular disease.

2. Caffeine Can Aid Fat Burning And Improve Metabolism

The caffeine contained in coffee and green tea is one of the few natural substances proven to aid fat burning and improve the rate of metabolism.

3. Coffee And Tea Can Be An Energy Booster

Coffee and tea can help boost your energy level and help you feel less tired. It is no wonder most people reach for a cup of joe first thing every morning!

4. Coffee And Tea Can Stimulate Brain Activity

Caffeine is known to stimulate brain activity. Recent studies show that it may protect against dementia and Alzheimer’s disease.

Alzheimer’s disease is one of the most common neurodegenerative diseases and the leading cause of dementia in the world. Studies show that coffee consumption can effectively lower the risk of this disease by 65%.


In conclusion, coffee and tea may exact diuretic effects when you consume them, but that doesn’t mean they make you dehydrated. The next time you reach for a cup of coffee or tea, enjoy it without feeling guilty about how it will affect your hydration levels.

While the intake of caffeinated tea and coffee may cause you to experience some diuretic effects, it doesn’t necessarily cause dehydration. However, it is still important to consume a variety of healthy fluids such as eating foods high in water content or drinking plain water.

For any comments, questions or feedback you might have, please send us a message through our contact form.

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Check-out the list of the products we recommend to help keep you hydrated throughout your day.

Be sure to consult your health care professional with any medical questions. Similarly, the information found in this article should not be considered medical advice.

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