Like most skincare products, sun creams should be used preferably within twelve months of opening. And even if there are some tips to keep them as long as possible, it is more than recommended to respect the length of the conversation indicated by the symbol representing a pot on the back of the packaging.
Octocrylene degrades to benzophenone
A Franco-American team of researchers, including the CNRS, is alerting to the fact that an organic sun protection filter frequently used in the development of sunscreens and anti-aging creams, the octocrylene, degrades within the vials into a carcinogenic compound and endocrine disruptor : benzophenone.
Researchers specify that industries that produce octocrylene know that this molecule is contaminated with benzophenone, and that the latter cannot be eliminated in its entirety during the production of octocrylene. In addition, the concentration of benzophenone in manufactured products octocrylene based is considered “negligible” by the cosmetics industry. “However, octocrylene naturally degrades into benzophenone even within the packaging,” they note. During his published study in the review Chemical Research in Toxicology, the team found that this substance was present in about 15 commercial products tested.
Dangerous for health and the environment
In addition, scientists have shown that the benzophenone concentration in these cosmetics is increasing rapidly with product aging. According to them, “the scientific community and the cosmetics industry admit that octocrylene and benzophenone are easily absorbed through the skin. A previous study had thus shown that the cutaneous absorption of benzophenone in the body can exceed 70%, a strong argument in favor of the regulatory ban of this product and of octocrylene in perfumes.and other topical products. As such, octocrylene no longer meets the safety criteria of the Food and Drugs Administration (USA), the US Medicines Agency.
And all the more so since “the accumulated scientific data indicate that it could be toxic for reproduction, and metabolic and endocrine disruptor “, Add the researchers. Finally, another French research published in 2018 in the journal Analytical Chemistry concluded that octocrylene is described as toxic for the environment: it affects, in particular, corals in swimming areas and potentially decreases the resilience of coral reefs to climate change. The fact that octocrylene-based products are contaminated with benzophenone in significant quantities, therefore, calls into question the safety of these products for public use.
The precautionary principle must apply
To date, octocrylene has already been banned in sun protection products in certain territories such as the United States Virgin Islands or the Republic of the Marshall Islands. Cosmetics containing octocrylene have also been banned in the Republic of Palau (Micronesia) since January 1, 2020. As explained The world which relays the study, the sunscreens and anti-aging creams purchased (brands such as Garnier, Bioderma, Uriage, La Roche-Posay or L’Oréal) have undergone an accelerated aging process validated in the United States, and equivalent to one year spent at room temperature. Then they were analyzed using a high-performance mass spectrometer.
“Initially, there is very little benzophenone in the products. But gradually with the aging of the product, there are more and more. Of increases in benzophenone exceeding 100% and even reaching 200% have thus been observed. This is the first time that this degradation of octocrylene into benzophenone has been shown ”, indicates Philippe Lebaron, from the biodiversity and microbial biotechnology laboratory at the Banyuls-Sur-Mer Observatory, co-author of the study. However, the IARC * has classified benzophenone as “possible carcinogenic to humans” while in the United States, it appears on the lists carcinogens and development disruptors.
According to the researchers, this new study is important because it provides new scientific evidence to argue that the octocrylene products, and therefore contaminated with benzophenone, can constitute a threat to public health as well as to the environment. “Our results plead in favor of the implementation of regulations dictated by the precautionary principle, the objective of which would be the protection of thepublic health and the environment », They conclude. The latter therefore advocate their ban in cosmetics knowing that we can also find octocrylene in self-tanning creams or shampoos.