 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 . Certain sunscreen ingredients can cause harm if they penetrate the skin over time . 
