Is Green Tea Hydrating?

Does Caffeine Dehydrate You?

There’s a common belief that drinking caffeinated drinks doesn’t hydrate you as well as water, or other caffeine-free beverages. This is because caffeine is known to have a diuretic effect, so it makes sense to assume that a caffeinated drink would have the same impact.

However, evidence to suggest this is the case is, at best, scant, especially in the 40-or-so milligram dose you’re likely to find in a typical cup of Green Tea. For example, a study conducted at Loughborough University found that, only when individuals abstained from caffeine for a number of days and were then given a dose equivalent to about 5-8 cups of tea (250-300mg), there was a temporary increase in their fluid output (they peed a bit more than usual). Doses equivalent to a normal cup of green tea were, on the other hand, found to have no diuretic effect, and they found that regular caffeine consumers became resistant to caffeine’s diuretic effects altogether!

Other studies have found a slight increase in fluid output when caffeine is consumed, however, even these did not find this increase was enough to outweigh the amount of fluid consumed when drinking a caffeinated drink like Green Tea. In fact, the NHS guidelines include tea and coffee in their guidelines of healthy drinks that can contribute toward your recommended 6-8 glasses of fluid a day.

So, if you’re concerned about drinking too much Green Tea in case it dehydrates you, the answer is that it’s probably absolutely fine to drink a few cups a day, and they do contribute to your recommended daily water intake. However, do be aware that some people should avoid caffeine altogether for other medical reasons, and even in people with no underlying conditions, excessive caffeine consumption can be troublesome. If you have any concerns about your caffeine intake, consult your doctor for advice.