Should you drink tea in a bottle?

Absolutely not. Bottled tea loses its antioxidants and many molecules are destroyed in this way, especially because it degrades over time in a liquid.
However the theine is still present and it is not the healthiest.

That's the conclusion of the American Chemical Society.

The brewed tea, especially green tea provides antioxidants. And other beneficial molecules. The theine is a form of caffeine, whose the effect on the body is slower and more sustainable. Thus tea is better than coffee.

But bottled tea contains less chemicals for health benefits. Professors Chi-Tang Ho and Dr. Li Shiming, who conducted an analysis on several of these beverages found there were virtually no antioxidants!

Specifically, while there are around 100 mg of polyphenols in a cup of brewed black tea, in a drink bottle, they are totally absent. It loses the primary virtue of tea, and taste they provide.

Manufacturers then want to add flavor to the drink and thus add sugar that is not good for the line, or health.