A formal study performed in Rome, Italy last year showed that a small amount of Tea-tree oil applied to the skin of Lab rats exposed to intense sunlight actually prevented the growth of melanoma and prevented the metamorphisis from one type of skin cancer to a more aggressive type. Several dermatologists in my area recommend "fungasoap". I wash with it everyday for protection. I am a surfer in florida. I buy it at Walgreens in the foot section. Great stuff.