“Tea is just as hydrating as tap water,” explains Kerry Ruxton, Ph.D., a nutritionist with the Tea Advisory Council and a researcher who has studied tea’s effects on hydration.

In fact, a 2011 study by Ruxton compared moisturizing effect of black tea and plain water1 directly. In the study, participants were given six cups of black tea throughout the day. Their hydration levels were measured, and then the experiment was repeated with the same amount of tap water. “The results showed no difference in hydration status,” Ruxton tells mindbodygreen.

This simulates the findings Beverage hydration index2, which measures how much certain drinks cause the body to retain or lose fluid over a four-hour period compared to water. Compared to coffee, which is slightly (but only slightly) less hydrating, thanks in part to its higher caffeine content, tea contains water. Caffeine has a diuretic effect, meaning it can cause you to lose more fluid through your urine than you retain.

According to Dana Cohen, MD, integrative medicine physician and co-author Beat Fatigue, Lose Weight, and Get Your Body Healthy With the New Science of Optimal Hydration, tea can be included in the daily norm of liquid consumption.

As a general rule, Academy of nutrition and dietetics3 recommends aiming for at least nine cups of fluid per day for women and 13 cups per day for men. However, they also note that fluid needs can vary depending on a long list of factors, including your age, gender, activity level and health.

Pro tip: Instead of sticking to a certain amount, Cohen recommends drinking enough fluids that you take a bathroom break every two to three hours to make sure you’re well-hydrated.