[kawfey]

I like to believe the calmness from tea comes from L-theanine, commonly present in tea leaves. https://en.wikipedia.org/wiki/Theanine

However, experimenting with putting theanine in coffee and consuming energy drinks with caffeine+theanine aren't as relaxing, perhaps because of the higher caffeine content, or other relaxing compounds in tea.

I drank about 40oz of coffee a day, and had the same symptoms if I stopped. I started replacing coffee with tea and the symptoms were a lot less severe. I'm now down to about 1c a day of coffee I grind and brew myself, as if it's a hobby enjoying the flavors and characteristics of different beans/grinds/brewing methods, not because I need caffeine to be a functional adult.