Body does not need any diuretic. It self regulates it's water level.
Those with poor health such as heart conditions need a diuretic/water pill so they do not retain too much water.
People get into trouble by ignoring that they are thirsty and sweating.
People that do strenuous physical work like the runners know they need to get fully hydrated. So they should drink lots of water once they get up before they start working then drink through out the day. As they urinate they will be able to tell if they are drinking enough.
There are the people that will have 3 cups of in the morning with breakfast. A cup or before lunch, cup with lunch, cup afternoon break. Lots of people drink 6 cups of coffee a day.
I do not need a scientist to tell me tea is a diuretic. I drink water through out the day. I have more then one cup of tea in the morning I will have to urinate more often on the same amount of water intake.
Can not tell my body tea/coffee is not a diuretic.