The New Tea Study’s Sweet Spot Is 6–8 Cups a Day — and That’s More Tea Than You Think
The biggest tea study of the year says 6 to 8 cups a day. That's nearly two liters, and for black tea drinkers it runs into the daily caffeine limit.
A study of nearly half a million people says the sweet spot for tea is six to eight cups a day.
The paper, published October 21 in the Journal of Internal Medicine, followed 485,934 Chinese adults for a median of nine years and found that people who drank tea at least three days a week had about an 11% lower risk of vascular disease — heart attacks, strokes, peripheral artery disease — than those who didn’t. That figure was adjusted for age, smoking, physical activity and weight. The benefit didn’t belong to tea alone, either. The lowest risk of all was among tea drinkers who didn’t smoke and stayed active.
Nobody in the coverage stopped at the number. Let’s.
Six to eight cups a day, using an ordinary 8-ounce cup, is 1.4 to 1.9 liters of tea. A day. Most people who think of themselves as tea drinkers don’t drink a liter and a half of anything, let alone tea. The study’s “sweet spot” is a serious habit, not a cup with breakfast.
Then there’s the caffeine. The Mayo Clinic puts an 8-ounce cup of black tea at about 48 milligrams, with strong brews running up to 70. At 48 milligrams a cup, six cups comes to 288 milligrams and eight cups to 384. The widely cited daily ceiling for caffeine in adults is 400 milligrams. In other words, the optimal dose in the study lands a black-tea drinker just short of the caffeine limit — and a strong-brew drinker right past it.
Green tea changes the math completely. At roughly 29 milligrams a cup, eight cups is only about 232 milligrams, barely half the ceiling. The study itself found black tea more consistently linked to lower risk than green tea, so there’s a trade-off buried in the numbers: the tea with the clearer association is also the one whose dose flirts with the caffeine cap.
Moderate-strength brew was linked to the lowest risk in the study — and tea drunk “burning hot” was linked to a higher risk of vascular disease, a finding about the vessels rather than the throat. For context, though, the temperature line has its own history: the WHO’s cancer agency classified drinking beverages above 65°C as probably carcinogenic back in 2016, based on esophageal cancer data, a different disease and a different mechanism. Freshly brewed tea comes out of the pot at 80 to 90 degrees. Letting it sit a few minutes is cheap insurance for more than one reason.
And one more detail the coverage mostly skipped: nobody knows what “a cup” meant. Cup size wasn’t standardized in the study. A Chinese participant’s cup and your 12-ounce mug are different instruments, so the 6-to-8 figure may not translate to your kitchen at all. Independent experts quoted on the paper made the same point bluntly. Queen Mary University of London’s Dr. Charalampos Rallis said the 6-to-8 figure “should not be read as a recommended intake,” and the British Heart Foundation’s Dr. Dell Stanford noted that intake was measured only once and the study can’t prove causation.
A cup or two still counts. The study’s regular drinkers were everyone at three days a week or more, not just the 8-cup champions. If you do drink a lot, black tea’s association looks stronger but green tea gets you the dose without the caffeine arithmetic. And whatever you drink, let it cool down first. The hottest finding in this study wasn’t the one anyone was hoping for.
