Smartwater has a Green Tea Ginseng Clarity drink that does help with alertness. Maybe that or green tea?
Tea and Chess

I favour Tetley's (or PG Tips) and perhaps a banana with it. I know that Eric Rosen mentions tea quite a bit in his videos whereas GingerGM maintains that beer helps him play better (seems more like the opposite tbh).

IM Eric Rosen drinks all sorts of tea while playing. Some Green teas help me concentrate but Chamomille puts me to sleep.

IM Eric Rosen drinks all sorts of tea while playing. Some Green teas help me concentrate but Chamomille puts me to sleep.
I made the mistake of playing a late night tournament and the chamomile kicked into 10 minutes of a rapid game. Felt sleepy and proceeded to give the game back despite being up a rook and bishop!
https://www.chess.com/game/live/39765541325
Anybody have experience with different teas and chess results?
I took up chess as a drinking game and recently switched over to chamomile or peppermint tea but my results have been better with alcohol funny enough.
Sober chess is something I will have to adjust for OTB.