Tea and Health

If you've noticed you need the bathroom more after a cup of tea, you're not imagining it. Tea does have a mild diuretic effect, but the explanation is more nuanced than most people expect, and "a bit more than water" is closer to the truth than "a lot more."

The role of caffeine

Caffeine is the main cause. It stops the kidneys from reabsorbing as much sodium, so more water gets passed out. At meaningful doses, caffeine is a well-documented diuretic. The effect depends on the dose: a small cup of green tea (25 to 40mg of caffeine) has a noticeably smaller effect than a strong cup of black tea (60 to 80mg).

Caffeine by type of tea:

• Black tea: 40 to 70mg per cup, the strongest diuretic effect of the teas
• Oolong: 30 to 50mg per cup, moderate
• Green tea: 25 to 45mg per cup, mild
• White tea: 15 to 30mg per cup, minimal

So if bathroom trips bother you, white tea is the practical choice. Our Fresh White Tea and Floral White Tea are both at the low end of the caffeine range, which suits the afternoon or evening when you want less caffeine.

Does tea count toward your daily fluids?

Yes, and this is often misunderstood. The UK's NHS, the European Food Safety Authority, and most nutrition guidelines agree that caffeinated drinks, tea and coffee included, count toward your daily fluid intake. The mild diuretic effect of caffeine doesn't cancel out the fluid you're drinking, so tea still hydrates you overall.

The one caveat is that at very high intakes, several very strong cups in quick succession, the diuretic effect can become stronger. At normal levels, 2 to 4 cups spread through the day, tea adds to your fluid balance.

How brewing affects caffeine

To cut caffeine, and with it the diuretic effect, without changing teas:

• Use cooler water. Hotter water pulls out more caffeine, so brewing green tea at 75°C instead of 85°C noticeably lowers it.
• Steep for less time. A 90-second steep extracts much less caffeine than a 3-minute steep of the same leaf.
• Drink the second infusion. Most of the caffeine comes out in the first steep, so a second steep of the same leaves has much less caffeine but keeps most of the flavour.

Herbal teas work differently

Not all teas have caffeine. Herbal infusions like chamomile, rooibos, and peppermint have none. Some herbal teas have diuretic compounds of their own: dandelion root is a well-documented natural diuretic, and hibiscus has organic acids with mild diuretic properties. For most herbal infusions, though, you won't need the bathroom any more than with plain water.

In practice

For most people, 2 to 4 cups of tea a day won't cause a problem with bathroom trips. If you do notice it:

• switch to a lower-caffeine tea (oolong, then green, then white)
• avoid big mugs of strong black tea in the evening
• spread your cups through the day instead of drinking several close together

Good whole-leaf teas from Nepal's high-altitude estates, like the black teas and oolongs in our Sampler Kit, have plenty of flavour with shorter steeps. That means less caffeine than the long steeping you need to get flavour out of commodity tea bags.

Frequently Asked Questions

Is tea more diuretic than coffee?
No. Coffee usually has 80 to 120mg of caffeine per cup, against 40 to 70mg for black tea, so coffee is a stronger diuretic than black tea and much stronger than green or white tea.

Will drinking tea dehydrate me?
Not at normal levels. The fluid in tea outweighs the mild diuretic effect of its caffeine, so tea hydrates you.

Does the type of tea bag affect caffeine?
Yes. Finer tea (the fannings and dust in most standard tea bags) releases caffeine faster and more completely than whole leaf. Whole-leaf tea in an infuser with a shorter steep usually gives you less caffeine than a standard tea bag steeped for 3 to 5 minutes.

What tea is best to drink before bed?
White tea, or a caffeine-free herbal tea like chamomile. Our Fresh White Tea has roughly 15 to 25mg of caffeine, little enough for most people to drink in the evening without it affecting their sleep.

Can I reduce caffeine in tea by "washing" the leaves?
A first 30-second rinse, poured away, does remove some caffeine, with estimates of a 20 to 40% reduction. A short rinse barely affects the flavour, so it's a reasonable trick if you're sensitive to caffeine but want to keep drinking your favourite tea.