SuperNumb® cream works by blocking the pain signal sent by the nerve endings on the skin. When applied to the procedure area as directed a feeling of numbness will follow. It is very important that the application instructions are followed as directed. You need to leave the cream and plastic wrap on the area for at least 2 hours prior to the scheduled procedure. Skin typically remains numb for 1 - 4 hours once cream is removed from treated area. The numbing effect depends on the skin type and the location on the body. For best result, use one 30g tube which covers approximately 6" x 6" area of your skin. For a long procedure lasting hours over large areas apply numbing cream over the entire work area then remove in sections as procedure progresses.