Not very convenient though:

> leave on for at least 1 minute before rinsing.

Why's that not convenient. I usually turn the water off while I apply soap and then turn it back on when I've finished to conserve water. That wait time is around a minute anyways. From talking to international friends this seems to be the norm around the world though I wouldn't be surprised if the average American doesn't practice this.

Not me. Water is on the whole time. I will move the body part I'm washing out if the stream long enough to apply lather, then immediately rinse it and then repeat. I would be surprised if there aren't at least a large minority that are at the two extremes here.

And caffeinated soap has been around a while, and I've been using it off and on. Some are good, some are not.

What prompted you to use caffeine soap when oral ingestion is so much more common/readily available?

Why not both?

Seriously, at the time, I was drinking gallons of coffee per day, and I appreciated the smell of the caffeinated soap. So, I actually did both.

These days, I'm decaffeinated on the coffee I drink, and I'm trying a variety of soaps, some of which are still caffeinated, and some are not.

You’d have to wait at least a minute after applying the soap.