Does Tea Hydrate or Dehydrate You?

Tea Cups
Tea cups. Photo by elpatojo.

Have you ever been told that tea dehydrates you? Whoever told you is wrong.

The claim that tea dehydrates is a long-standing myth. While tea does contain caffeine, it only starts to have a diuretic effect once you’ve consumed 300mg. It’s also been found that most tea drinkers are safe to consume up to 400mg a day (though pregnant women should limit their caffeine intake to 300mg). Considering the average cup of tea has less than 50mg of caffeine, even the most prolific tea drinkers should be pretty safe.

So there you have it. Tea hydrates. Just thought you ought to know.

Need more evidence? Check out this study that looked at the hydration vs. dehydration question, among other important issues.


  • 1

    That was an interesting post! And you are quite right that just about all of us are safe if it takes 8 cups before a diuretic effect even begins. Good news!

  • 2

    This would sort of depend on what a “cup of tea” is defined as. Are we talking about a two, three, or six ounce cup; or are we talking about an “imperial cup” (eight ounces).

    Some folks just brew a big ol’ pot of tea and keep drinking till it’s gone.

  • 3

    Good question Frank. The introduction to the study puts the average daily intake at 540 ml (for 3.2 cups), so that’s 234 ml, or 8 ounces. A pretty sizable cup of tea in other words!

  • 4

    This is completely subjective, of course, but I find that black teas re more likely to feel ‘hydrating’ to me whereas greens or oolongs quench my thirst for a shorter period of time… I have no idea why this is!

  • 5

    That’s interesting Verity. I wonder if it’s due to the fact that greens and oolongs can sometimes be a bit more drying of the mouth, due to the tannins; though of course if you over-brew a black tea it will pucker your mouth like anything.

  • 6

    The main article had very good insight. This is the first site which I think explains it well. I know somebody who drinks a lot of tea, green tea that is. He said about 6 cups a day. Based on what I see on line green tea has about 40 mg of caffeine I believe. Wikipedia is a excellent start of information. For instance black tea is close to 100 mg of caffeine so you weren’t drink 6 cups a day. White tea is extremely low. Again go to Wikipedia and type in tea.

    I just brewed loose green tea this morning and it was in a sample pack so I’m not sure if the tea is good or not. I might have left it in the water too long it was extremely dry and it tasted very off. One of two things or two things could have happened. It was a very bad green tea or I left it in too long.

    Going with the main article, I seen on different sites that herbal tea does not have any caffeine in it. So you can drink this instead of plain water to hydrate you according to what I read. Is this true?

    Tea carries a lost of antioxidants which is good for the body, different tea do you different things. I’m not sure what herbal tea does for us besides give us a different option from drinking water on a cold evening and I’m not even sure about that. Anyway, I hope I made some sense.

  • 7

    I am an extremely prolific Iced Tea drinker. I drink a LOT. All day I have my glass at my side.

    I normally use either Lipton or Luzianne iced tea sized bags – Lipton is what I have on hand now.

    According to the box this has 45mg of caffeine per 8 oz serving (where 8oz = 1 cup) brewed according to the following directions…

    brew 2 bags in 4 cups of boiling water, then cut with 4 more cups of cold water.

    8 cups x (45mg caffeine/ 1 cup) = 360mg caffeine

    So a half gallon has 360mg with their method. Personally, I use a drip coffeemaker to brew my tea. I don’t know if it is more effective this way, but I end up getting 1 gallon and 1 quart, or 20 cups, out of the same two tea bags – and it tastes like moderate restaurant tea. Even if the coffeemaker is 150% as efficient at getting the goodies out of the bag, that’s only {(1.5 x 360mg caffeine) / 20 cups = 27mg per cup}.

    Soooo much better for you than soda.

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