Irish,
I've actually heard that PPG in the minoxidil as a carrier vehicle is responsible for about half (don't quote me on that) of the results that you see from minoxidil formulations with PPG included. I'm not sure if that means that a plain PPG liquid with no minoxidil would work, but there you go.
That makes me wonder whether or not minoxidil formulations without PPG like some of Dr Lee's work. And how carriers matter is interesting as well.