A sun protection factor (SPF)-15 and an SPF-30 sunscreen were compared with regard to their ability to prevent sunburn cell formation after the exposure of human skin to a standardized dose of solar-simulated radiation. The SPF-30 sunscreen provided a significantly superior degree of photoprotection and almost prevented sunburn cell induction. Because sunburn cells may be markers of ultraviolet radiation-induced damage to DNA, the new superpotent sunscreens should offer an advantage in the prevention of skin cancer and long-term actinic damage to skin.