Why lemonade is the best thirst quenchers?

Lemonade is not the best thirst quencher, actually water is.

The thing with lemonade is that the high concentration of citric acid stimulates your saliva glands and this causes you to feel less thirsty (of course this is for NATURAL lemonade, not the branded drinks they call "lemonade"). The sugar in the lemonade will somehow eliminate this effect, and if the lemonade is too sweet, instead of feeling quenched you might feel even more thirsty.

My advise would be to mix a big cold glass of cold water with a couple teaspoons of natural lemon juice for the best thirst quenching drink!