Current sunscreen controversies: a critical review

Abstract

SummaryBackground/purpose: Sunscreens are believed to be a valuable tool in providing photoprotection against the detrimental effects of UV radiation, a known carcinogen. However, a number of controversies have developed regarding their safety and efficacy. This review summarizes the relevant studies surrounding these controversies. Methods: Evidence of the prevention of skin cancer, an oft-cited reason for sunscreen use, was examined as it pertains to squamous cell carcinoma, basal cell carcinoma and melanoma. We 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, we analyzed studies surrounding the safety and toxicity of oxybenzone, retinyl palmitate and nanoparticles of zinc oxide (ZnO) and titanium dioxide (TiO 2 ). Results: The overwhelming majority of available data is drawn from studies conducted using antiquated sunscreen formulations. Nonetheless, our research revealed that topical use of sunscreen protects against squamous cell carcinoma, does not cause vitamin D deficiency/ insufficiency in practice and has not been demonstrated to adversely affect the health of humans. Conclusion: Given the established benefits of UV protection, the use of sunscreens remains an important part of an overall photoprotective strategy. Future sunscreens with improved formulation should ideally offer superior protection. With increased usage of sunscreen by the public, continuous and vigilant monitoring of the overall safety of future products is also needed.

Sunscreen and Melanoma: Is Our Prevention Message Correct?

“…Based on currently available information, the "harm" related to sunscreen use is probably not intrinsic to sunscreens 33 ; it is more likely related to the improper use of sunscreen, resulting in more sunburns. [7][8][9] Primary care providers who encourage the use of sunscreen should also instruct patients about the proper use of sunscreen to avoid sunburns.…”

Zinc oxide nanoparticles: a 90-day repeated-dose dermal toxicity study in rats

“…The surface charge was modified with coating reagents, citrate for (-) charge (ZnO SM20(-) ), as reported previously. 6 On scanning electron microscopy, ZnO SM20(-) were determined to be an average of 29±3 nm and to be spherical in shape. The zeta potential of ZnO SM20(-) was -44.4±1.0 mV, with a negative surface charge.…”

Synthesis and <i>In Vitro</i> Evaluation of C-methylcalix[4]resorcinaryl octacinnamate and C-methylcalix[4]resorcinaryl octabenzoate as the Sunscreen

“…It is well known that both acute and chronic sun exposure induce biologically and clinically detrimental damaging effects such as sunburn, immunosuppression, photoaging and skin cancer [1][2]. Mironava et al [3] have reported that commercials compact fluorescent light (CFL) bulbs emit UV-A and UV-C light, which can induce to various types of skin cancer.…”