Well, that isn't the whole story. Sunscreens do protect skin from sunburn, but a scientific debate simmers about the role of lower-energy ultraviolet light in skin damage and whether current sunscreens provide adequate protection. In recent years, however, it has become apparent that a different form of ultraviolet light, called UVA, may be even more important in causing some skin disorders. Most sunscreens do a good job blocking UVB, but fewer sunscreens filter out most of the UVA, so they do not help to prevent the beginnings of melanoma formation. While cancer treatments continue to improve, melanoma recovery rates remain disappointing.
Prevention is the better solution.
As prevention, however, sunscreens alone appear to be imperfect. But using sunscreen did not reduce the risk of developing melanoma or basal cell carcinoma. The Australian study followed 1,383 adults for five years. But the melanoma rates are still high in older people whose skin was damaged by sun exposure years ago. Although it may seem backwards, the shorter the wavelength and the lower the number, the greater the energy level of the light and the more damage it can do.