Radiofrequency (RF) skin tightening is a nonsurgical method of tightening your skin. The procedure involves using energy waves to heat the deep layer of your skin known as your dermis. This heat stimulates the production of collagen. Collagen is the most common protein in your body. It creates the framework of your skin and gives your skin its firmness. As you age, your cells produce less collagen, which leads to sagging skin and wrinkles. Skin laxity occurs around age 35 to 40 when the quantity and quality of your collagen begin to decline.