How does caffeine affect osmosis?

Answer 1

Caffeine is classified as a diuretic, which means that it increases urine output.
The primary reason why urine increases urination is that it increases golmerular blood pressure,
or blood pressure within capillaries in kidneys. This, in turn, increases blood filtration,
resulting in an increase in urine.
Another reason why caffeine is a diuretic is that it prevents sodium ion resorption--or,
increase in sodium ion blood serum levels--which increases urination, but decreases water filtration.
This is because water filters from the blood through the kidney and into the
bladder during sodium ion resorption. Given that caffeine prevents the resorption process,
water filtration is likewise inhibited.