Does coffee improve your game?

I do better if I have Doritos handy to munch on while I play.

All that crunching has the added effect of distracting your opponent!

Coffee helps concentrate becourse it makes brains to produce dopamin, witch helps concentrate

Yes, it contains liquid elo

Coffee contains caffeine which increases alertness and enhances the performance.

Coffee just makes me struggle with sleeping, so I HIGHLY doubt it will help.

Yeah cofeine, i forgot to say, but its kind of understandable

I think you mean "covfefe".

...

covfefe LOL

I guess it depends on you. But in general, I think it is safe to assume that coffee's side effects will help you to concentrate, to be awake, etc. And as long as your game doesn't last too long, it won't harm you (however, FIDE doesn't like coffee much, I remember reading about some master who retired from competitive chess after the "ban" on coffee, reason being he wanted to play his opponents when they were the most capable - however, I've forgotten since who that was...). 

In case you are looking to enhance your performance, I too give the advice: Study the game, exercise your mind and body. Taking coffee will only help - however, you need your intuition, etc. so that it can be enhanced - so to speak, you'll always need a few building rocks.

And I personally advocate for the use of green tea - that will kick in slower, yes, but it will last not only longer, no, it will also be even more effective! I have forgotten FIDE's regulations on substances, however.

(Without my morning coffee, I am just a zombie - not capable of anything!)

The main thing is to feel good to play

lol