Any clinical trials that can attest to it's efficacy?
Not that I know of. I went off reviews of what people said. I did a lot of research before I bought it. It's bentonite clay. You need to add water and stuff to it yourself.
I use water and apple cider vinegar in it. If you don't like the feeling of slight burning then leave out the vinegar, but I find best results with it. When it dries your skin will feel really tight and you will feel like its pulsing. I remove it after about 40 minutes and my skin feels really smooth after. I suggest you look up bentonite clay. Two pounds is about $12.
I suggest you get the Aztec Secret brand if you're interested. Has over 50 mineral compounds.