Hentham comments on How do I use caffeine optimally?

[Hentham]

Caffeine does not dehydrate you — in fact, it appears to be about as hydrating as water.

[trevor]

Yes, and cigarettes reduce the risk of lung cancer.

This sort of thing is not new.

[randomstring]

Caffeine: Is it dehydrating or not? - Mayo Clinic

Does Coffee Dehydrate You? (healthline.com)