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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.4
It is difficult to draw generalizable conclusions when both the method and concentration of exposure that model organisms receive do not replicate human chemical exposure. Despite the fact that our functioning skin barrier limits much of our systemic exposure to chemicals in personal care products, many animal studies,5 including the one cited by Drs Gore and Cohn, rely on protocols in which model organisms are fed or injected with the compound of interest, limiting the generalizability of these studies. Although the 2019 JAMA article by Matta and colleagues demonstrated systemic absorption of sunscreen agents, the authors also highlight “the need for further studies to determine the clinical significance of these findings”6(p2082) and their conclusion that “these results do not indicate that individuals should refrain from the use of sunscreen.”6(p2082)
We accept the fact that long-term exposure to certain concentrations of formaldehyde can lead to health risks, such as allergic contact dermatitis, asthma, irritation, and cancer, in laboratory animals and humans. However, this needs to be kept in the proper perspective, as the amount of formaldehyde found in personal care products is extremely low and is typically a byproduct of the manufacturing process or is released in small amounts from certain preservatives. Because formaldehyde is also an endogenous byproduct of the human metabolism, small amounts of this substance are ubiquitous in our environment, including in textiles, in construction materials, in the air we breathe, and in our bodies. The Cosmetic Ingredient Review has established guidelines for industry on safe limits of formaldehyde in personal care products.
Corresponding Author: Bruce A. Brod, MD, Perelman Center for Advanced Medicine, Department of Dermatology, University of Pennsylvania, 3400 Civic Center Blvd, South Pavilion, Philadelphia, PA 19104 (firstname.lastname@example.org).
Published Online: March 18, 2020. doi:10.1001/jamadermatol.2019.4661
Conflict of Interest Disclosures: None reported.
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Rubin CB, Brod BA. Endocrine-Disrupting Chemicals in Cosmetics—Reply. JAMA Dermatol. Published online March 18, 2020. doi:10.1001/jamadermatol.2019.4661
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