Courtney Blair Rubin’s research while affiliated with University of Pennsylvania and other places

We thank Drs Gore and Cohn for their interest in our article¹ and thoughtful comments. We agree that ongoing research is needed; however, we would like to point out several issues. First, many parabens are, in fact, not banned in the European Union. The European Union has banned 5 longer-chain parabens not because of evidence that they are unsafe, but rather because “no information was submitted by industry for the safety evaluation [of these compounds].”² All of the most commonly used parabens, including methylparaben, ethylparaben, propylparaben, and butylparaben, along with many others, are considered safe and legal for use as preservatives in Europe.² Although many researchers in the clean beauty movement have expressed concerns about the potential for endocrine disruption by parabens, studies in rats and yeast cells have shown parabens to be thousands to millions of times weaker than estradiol, an endogenous sex hormone.³ Given that women are exposed to much more potent natural estrogens, along with estrogens in oral contraceptive pills and even phytoestrogens in food, the extremely weak estrogenicity of parabens is unlikely to be meaningful. The Cosmetic Ingredient Review has done an extensive investigation of the scientific literature on paraben safety and has concluded that parabens are safe in personal care products. The US Food and Drug Administration has also concluded that parabens are safe when used in personal care products.

Clean beauty, also known as natural skin care, is having a moment. From 2017 to 2018, the natural skin care market grew by 23% to 1.6 billion dollars, accounting for over 25% of the 5.6 billion dollars of annual skin care sales in 2018.¹ Staunch warnings from influencers such as Gwyneth Paltrow, whose blog Goop warns readers “Do you want antifreeze (propylene glycol) in your moisturizer? We’re going to guess no,”² have ignited fear in consumers who are now hungry for skincare that is safe and nontoxic. However, the US Food and Drug Administration (FDA) has failed to define clean and natural, leaving these labels open to interpretation by nondermatologist retailers, bloggers, and celebrities who have set out to define clean beauty for themselves. While the clean beauty movement has demonized hundreds of compounds, in this Viewpoint, we argue that an arbitrary designation of clean or natural does not necessarily make products safer for consumers.