Green tea. Once you get to the end of the day have a glass of green tea, there are many varieties so with some experimentation chances are you'll find one you l

Green tea. Once you get to the end of the day have a glass of green tea, there are many varieties so with some experimentation chances are you'll find one you like. Green tea has a little caffeine as well as the amino acid l-theanine which works with caffeine to improve your brain function. My personal experience suggests that whatever it is, there's something going on that works really well.