Sunscreens are a valuable tool for providing photoprotection against the detrimental effects of ultraviolet (UV) radiation, a known carcinogen. However, several controversies have developed regarding their safety and efficacy. 

The present study examined evidence of the prevention of skin cancer, an oft-cited reason for sunscreen use, as it pertains to squamous cell carcinoma, basal cell carcinoma and melanoma. It also reviewed studies examining the effects of sunscreen on the synthesis of vitamin D, an essential nutrient whose role in health and disease continues to grow. Lastly, it also analyzed studies surrounding the safety and toxicity of oxybenzone, retinyl palmitate and nanoparticles of zinc oxide (ZnO) and titanium dioxide (TiO₂).

The majority of available data came from studies conducted using antiquated sunscreen formulations. The research found that topical use of sunscreen protects against squamous cell carcinoma, does not cause vitamin D deficiency/insufficiency in practice, and does not affect the health of humans adversely.

The established benefits of UV protection make sunscreens an important part of an overall photoprotective strategy. In the future, sunscreens with improved formulations should provide superior protection. Furthermore, the increased sunscreen usage by the public demands continuous and vigilant monitoring of the overall safety of future products.

Source: Burnett ME, Wang SQ. Current sunscreen controversies: a critical review. Photodermatol Photoimmunol Photomed. 2011;27(2):58-67.