Why does the caffeine in coffee make us need to use the restroom, but the caffeine in soda doesn’t, despite being around the same amount of stimulant?

Question

Edit: I do not usually drink colas, I prefer clear sodas.

Mountain Dew is my favorite. When I think of having a Mountain Dew, I usually think of the 20 oz bottles. I don’t keep soda cans in the fridge.

When I have coffee I usually have the normal 12 oz over ice.

12 oz of coffee is more or less 100 mgs of caffeine. 20 oz of Mountain Dew is more or less 100 mgs of caffeine. This is why I said, “about the same amount of caffiene,” in my title.

I understand the confusion, and appreciate y’all caring enough to try and correct me in the comments. Hopefully this cleared some things up!

In: 127

Answer 1

A typical dark roast used in drip brewing averages around 24mg/oz. while soda is only 4mg/oz. Comparing equal amounts of coffee (three cups) to a can of soda, your caffeine content is ~ 300mg vs 50mg. Additionally, coffee has more dissolved solids and organic molecules which increase the osmolality of your plasma, making your kidneys work more.