6 Reasons Why Tea Is Dehydrating When You Drink It Improperly

Tea does not dehydrate you, but there are a few exceptions. Here are six reasons why tea is dehydrating if you don’t drink it correctly.

man touching his forehead after drinking from a glass cup - why tea is dehydrating
Incorrect consumption of tea causes dehydration

I’m nowhere close to being an obsessive tea drinker – but I must admit that the huge tea collection at home makes me proud. And I’m not just talking about green tea or tea bags. I have chai tea, lemon ginger tea, chrysanthemum tea, rose bud tea, and even butterfly pea flower tea.

I drink tea every day – but sometimes, a serious question pops into my mind while kicking back with a hot cup in my hand: How much tea is too much? And Is there any chance I’m losing my hydration to tea?

Well, I did some research to learn whether upping my tea intake does more harm or good. The good news is: that tea is not directly dehydrating you. But in some rare cases, it may – especially when you don’t consume it correctly. 

Here are six scenarios when drinking tea may cause dehydration.

1. When There’s More Caffeine Than Water

Tea cannot be consumed without diluting it in water. It’s hard to determine the exact percentage, but generally, there’s much more water than caffeine in black or green tea. So, the diuretic effect of caffeine is much lower than the amount of water you absorb.

Herbal tea is not likely to cause dehydration as it doesn’t contain caffeine. One gram of green tea has about 11 to 19 milligrams of caffeine.

Each type of tea requires a certain amount of water to brew. A significant drop in water intake compared to the caffeine level will contribute to the diuretic effect. You’ll be fine if you keep your daily tea consumption under control at less than four cups a day.

You might find our explainer on what percentage of tea is water useful. 

2. You Regularly Overconsume Tea

According to a study, you should not have more than three cups of green tea a day. Overconsumption of this recommended amount over time will lead to nausea and vomiting.

Why tea is dehydrating
You should not have more than three cups of green tea a day

Even though there is still an ongoing debate about the best amount of tea to be consumed daily, you still need to drink a lot of high-caffeine tea to experience a noticeable difference. Any amount of caffeine greater than 400 milligrams a day is probably too much. 

If you cannot live without tea, try herbal tea.

3. When You Drink Too Much Sugar-Infused Or Sweetened Tea 

Excess sugar may lead to cell damage and dehydration. Sugar triggers dehydration because it moves the water out of the cells to equalize the sugar concentration stationed outside the cells.

Excess sugar in the body messes up insulin levels, energy levels, and more. Your body needs more water to metabolize a significant amount of sugar, which can worsen dehydration. 

4. Caffeinated Herbal Tea May Cause Fluid Imbalance

As mentioned above, herbal teas do not contain caffeine; therefore, they are not a cause of dehydration. 

However, there are some exceptions to herbal teas. 

Let’s take Yerba Mate. This popular traditional drink from South America is made from the dried leaves and twigs of the Ilex paraguariensis plant. Each cup of Yerba mate contains around 85 milligrams of caffeine, a tad higher than regular tea but less than coffee.

5. Tea May Cause Nausea That Leads To Fluid Imbalance

There is a connection between nausea and dehydration. Those who experience severe nausea find drinking enough water and taking in other fluids difficult. Vomiting also contributes to fluid loss.

A few properties in tea may cause nausea if consumed in large quantities or on an empty stomach; for example, tannins can be astringent and irritate digestive tissue.

However, not everyone responds to the nausea side effect of tea the same way. Some people with a severe sensitivity to tea may experience nausea and fluid imbalance after drinking as few as one to two cups, but that’s not always the case.

6. Tea May Cause Heartburn

Last but not least, let’s address acid reflux. The caffeine in tea is likely to result in heartburn and aggravate pre-existing acid reflux symptoms if overconsumed. The reason behind this effect is the way caffeine relaxes the sphincter that separates the esophagus from the stomach.

a woman pressing her hands on her chest
Caffeine in tea causes acid reflux which leads to heartburn

As a result, the acidic stomach contents flush into the esophagus more frequently, leaving a scar on the esophagus lining. Without prompt treatment, the scar tissue builds up, leaving behind a narrow esophagus known as strictures. So, if it’s harder to swallow liquids, it’s easy to become dehydrated.

If you liked this post, you might also enjoy our What percentage of tea is water?


  • Oanh Nguyen

    Born and raised by a traditional mama-barista, Oanh is a typical Viet coffee aficionado who would spend her entire precious Sunday showing you how to categorize coffee beans just by the looks and smells. She enjoys writing about everything drinks-related while sipping her favorite rosebud tea. Find Oanh on LinkedIn.