I got this foot peel mask for Christmas and I was very excited! I put the booties on and kept them on about an hour and a half. There was a slight burning on the tops of my feet and when I took the booties off I did have a spotty red rash on the tops of my feet. On day 2 I was wondering what on earth I had done to myself because the rash was still there and my feet felt desensitized, were itchy and still burning a bit. But...they started to peel on day 3 and continued until day 6. It was extensive! Full sloughing. And in the end my feet were smoother than they have been in years and the rash is gone...so, effective maybe mildly irritating but I'm pretty sure I'll use the second in the pack in the future.