50% is very high of a percentage for most to start out (begin with). I luckily washed it off in less than 40 seconds, having baking soda and water to neutralize it right away. The product worked well for me. It did arrive with most of the label unreadable and the top had no seal other than being scotch taped. I am happy with the product, but recommend others use 20%, and should know how to handle the product being very careful (cautious). There will be 5 days or more of the skin peeling as your skin tries to heal. It's as if you have a suntan peeling away. Use a good moisturizer these days.