system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Does drinking a caffeinated drink actually dehydrate you?

So I know caffeine is a dieretic (tough word for a 5yo), but when you drink a soda or coffee, you are also taking in a fair bit of water. So does it just hydrate you *worse* than drinking the same volume of water, or does it actually make you less hydrated than if you'd drank nothing?

Or is there a cutoff point, where drinking a certain amount of caffeinated drink goes from hydrating to dehydrating?
gpt
No. 

Caffeine is a mild diuretic and will cause your kidneys to process water and produce urine faster than not consuming it. But the concentrations needed to counter the volume of water consumed in the drink would be close to a lethal dose.