How does caffeine affect the urinary system?

Caffeine acts as a diuretic, which means it increases urine production. This effect occurs because caffeine inhibits the reabsorption of sodium in the kidneys, leading to increased sodium and water excretion. The presence of caffeine can affect various parts of the nephron, particularly the proximal tubule, thereby promoting diuresis—the increased production of urine. This is why beverages containing caffeine, such as coffee and energy drinks, can lead to more frequent urination.

In contrast, caffeine does not decrease urine production, promote kidney stone formation directly, nor has a neutral effect on the urinary system. While high calcium intake from certain sources can contribute to kidney stones, caffeine itself is not primarily responsible for this occurrence. Thus, the primary action of caffeine that is pertinent to the urinary system is its diuretic effect, leading to increased urine output.