Coumarin in cosmetics: Clarifying the safety controversy

Sheryl P Denker, PhD, Senior Strategic Content Manager, SherylDenker@eurofinsUS.com; Ellen L Berg, PhD, Chief Scientific Officer, EllenBerg@eurofinsUS.com; Thierry Jolas, PhD, Study Director, ThierryJolas@eurofins.com; Eurofins Discovery.

If you’re like most people, you have likely washed your hands more frequently during the COVID-19 pandemic, and you may have experienced additional dry skin as a result. Maybe you’ve been using more lotion, and perhaps wondering, is this product safe? In the United States, the European Union, Asia and globally, each cosmetic manufacturer is responsible for ensuring their products are safe for consumers, but the methods for determining safety risks are independent decisions. In the US, with the exception of color additives, the Food and Drug Administration (FDA) does not enforce approval authority over cosmetics, but does regulate cosmetics for safety and labelling, including for fragrances and other ingredients. Testing of individual cosmetic ingredients is, however, an active programme within the Environmental Protection Agency’s (EPA) ToxCast Program. In the EU, cosmetic testing includes regulations that ban animal testing, and in Asia, according to Eurofins, toxicology testing is increasing in demand. As consumers become more health conscious and sophisticated about reading labels, companies need to emphasise the safety of ingredients that go into their products while balancing testing and regulatory guidelines.

Enter the coumarin controversy. Since the late 1950s, coumarin in food has been under scrutiny for safe upper limits related to carcinogenicity and liver toxicity in animal models. Coumarin (found naturally in tonka beans, lavender, cassia cinnamon, and sweet clover) is an aromatic lactone used by the cosmetics industry as a fragrance in perfumes, bath and shower products, lotions, and deodorants (and by the e-cigarette industry in vaping products). In 2004, although scientists and regulators determined genotoxicity was not a relevant toxicity mechanism if daily intake remained below threshold doses, concerns around coumarin continued.

In 2020, a team from the Unilever Safety and Environmental Assurance Centre published a study that leveraged Eurofins Discovery’s global portfolio of safety assays to show that coumarin in personal care products has a low safety risk at exposure levels expected from application of face cream and body lotion twice daily. Taking an animal-free approach, this team used the Tier 1 SafetyScreen44™ Panel and all-human, primary cell-based assays of the BioMAP^® Phenotypic Platform to assess the biological activities of coumarin relevant for a human safety risk assessment. The study, “A Next-Generation Risk Assessment Case Study for Coumarin in Cosmetic Products”, published in Toxicological Sciences and presented to the US EPA, demonstrates the success of a major company in the cosmetics industry in assessing safety without animal testing. For more information, visit Eurofins Discovery at BioMAP Platform or SafetyScreen.