I'm the neck clench poster boy!
Unfortunately.
Studies have shown that people think better and faster after a brisk walk. Presumably due to increased circulation. Sugar helps too, though I would prefer whole fruit over liquid sources for better long term health.
Though it costs more time than downing a caffeinated drink, a combo of hydration, stretching, walking and fruit should charge the brain.
Ahem, not that I'm in the choir. I still drink 1 cup of tea per day even though I do some of the above.