In-Vivo and In-Vitro Endocrine Activity and Toxicity of Oxybenzone (Benzophenone-3) in Humans and Animals: A Systematic Review

Oxybenzone (also known as benzophenone-3 or 2-hydroxy-4-methoxybenzophenone) is one of the most commonly used organic sunscreen agents worldwide. Widespread use of oxybenzone (BP-3) over the last several decades has resulted in the occurrence of this compound throughout the environment. BP-3 and its metabolites have been identified in rivers, lakes, indoor dust, and even drinking water. Additionally, BP-3 has been detected with high frequency in human urine, and has been found in placental tissue, amniotic fluid, and breast milk. As a phenolic compound with some similarities to bisphenol-A, the widespread presence of BP-3 throughout the environment has resulted in growing concern regarding its potential endocrine disrupting effects. The objective of this paper was to systematically review the evidence on the endocrine disrupting activity of BP-3 to better understand and characterize the specific effects this compound may have in humans and other animals. A total of 62 studies were identified in this review, which collectively provide evidence for significant estrogenic, antiandrogenic, thyroid, and reproductive/developmental effects meeting the World Health Organization’s definition of an endocrine disruptor. However, due to the vast heterogeneity in study design and execution in the existing literature, it is difficult to make adequate between-study comparisons and characterize the true clinical significance of these findings. In the future, more standardized research needs to be conducted to identify the specific conditions of BP-3 exposure that may impart negative health outcomes.