Tea Keeps You Just as Hydrated as Water So, drink away, caffeine lovers By Evann Gastaldo, Newser Staff Posted Apr 2, 2011 6:36 AM CDT 11 comments Comments This will keep you just as hydrated as water, a new study shows. (?usadifranci) (Newser) – Good news, tea lovers: You know all that water you're supposed to drink every single day? Well, you can substitute tea for at least some of it, a new clinical trial shows. Despite the fact that tea is caffeinated, the study shows that four to six mugs of it per day will keep you just as hydrated as the same amount of water, with no negative health effects. Of course, it's worth noting that the Tea Advisory Panel commissioned the study, which was published in the British Journal of Nutrition. Volunteers in the trial drank either four mugs of tea (with semi-skim milk, but no sugar) over 12 hours, or a similar amount of boiled water (about one liter), served warm. Then the test was repeated using six cups, or about 1.5 liters. During the study, volunteers were not allowed to exercise vigorously or consume other caffeine or alcohol. Blood samples showed no significant difference in hydration levels between the tea drinkers and the water drinkers, the Daily Mail reports.