As bikinis leave most of the body exposed to potentially dangerous UV radiation, overexposure can cause sunburn, skin cancer, as well as other acute and chronic health effects on the skin, eyes, and immune system. As a result, medical organizations recommend that bikini wearers protect themselves from UV radiation by using broad-spectrum sunscreen, which has been shown to protect against sunburn, skin cancer, wrinkling and sagging skin. There have been concerns regarding certain sunscreen ingredients causing harm if they penetrate the skin over time, however according to current research, sunscreen has not been demonstrated to adversely affect the health of humans.