Nope, only true in extreme cases. I was curious about that years ago, and while it might make you need to urinate more frequently, it doesn’t actually make you urinate more volume unless you consume way more caffeine than your body is used to. Now, alcohol on the other hand, anything over like 3-5% ABV does have a net dehydrating effect.
Caffeine in the coffee is a diuretic though. It’ll make you lose more water through urination than if you drank the equivalent volume in just water.
Although caffeine is a diuretic, coffee is net hydrating.
https://health.clevelandclinic.org/coffee-dehydration
Nope, only true in extreme cases. I was curious about that years ago, and while it might make you need to urinate more frequently, it doesn’t actually make you urinate more volume unless you consume way more caffeine than your body is used to. Now, alcohol on the other hand, anything over like 3-5% ABV does have a net dehydrating effect.
This doesn’t actually seem to be completely true. The diuretic effect isn’t enough to really impact the benefits if drinking a 99% water solution.