Top brand suncreams become carcinogenic if left on the shelf too long, claim French researchers
Some of the world’s most popular sunscreens risk causing cancer if left on the shelf too long because a commonly used sun protection factor breaks down into a harmful ingredient, top US and French researchers claim. Millions of families buy sunscreen when they go on holiday only to keep unfinished tubes and re-use them when they head for the sun months later. However, a Franco-American study published in the Chemical Research in Toxicology review on Monday found that if left for a year at room temperature, such products become potentially toxic as one of their key ingredients breaks down into a product called benzophenone, which they say is a “mutagen, carcinogen, and endocrine disruptor”. Scientists at France’s CNRS, Sorbonne Université, the Oceanological observatory in Banyuls-sur-mer and the Haereticus Environmental Laboratory in Virginia, USA, made the discovery after experiments on nine commercial sunscreen products from the European Union and eight from the United States. Many can be found in the UK. All but one contain octocrylene, which is present in most sunscreens but also anti-ageing creams, shampoo, tanning oils and conditioners. While the active ingredient is approved for use in sun protection factor in the US and EU, it is controversial as it poses a risk to marine life and in particular coral reefs, making them more susceptible to bleaching. As a result, skin products containing the ingredient have been banned in Palau, the Marshall and the US Virgin Islands, and a ban is currently up for debate in Hawaii. However, this new study focuses not on octocrylene itself but on whether it breaks down over time to produce benzophenone, considered potentially more harmful to man and banned in food products or food packaging in the US. Under California Proposition 65, benzophenone is also banned from personal care products, including sunscreens, anti-ageing creams, and moisturisers. While not outlawed in the EU, the bloc’s Scientific Committee on Consumer Safety last month recommended placing new limits on use of benzophenone, as well as octocrylene, in cosmetic products compared with current requirements under the European Cosmetics Product Regulation. In the study, the researchers picked the creams at random “directly from stores” after asking for the most popular brands, and artificially aged the products over a six-week “incubation period” to create the same conditions as if they had remained in someone’s home for a year. Only one product contained no octocrylene – Nivea Sun PF 50+. At the end of the ageing process it was found to contain no benzophenone. However, all the others, which did contain octocrylene, ended up with far higher amounts of benzophenone at the end of the process. “Benzophenone is well-known as a mutagen, carcinogen, and endocrine disruptor, notably among mice and rats even if it is not proven in man,” said Philippe Lebaron of Sorbonne Université. “The problem is this molecule crosses the skin barrier and is thus potentially dangerous for humans. The fact that octocrylene breaks down into benzophenone should be sufficient not to use it anymore,” he suggested. In the EU samples, anti-ageing cream L’Oreal Age Perfect FPS 20 had the highest concentration of benzophenone both at the start and after ageing, seeing an almost 200 per cent rise in benzophenone to 214 milligrammes per kilogramme. Next was Garnier Ambre Solaire FPS 50, which saw a 122 per cent rise. In the screens bought in the US, the biggest rise was seen in Coppertone Sport Clear SPF 30 – up 134 per cent to 408 mg per kg, the highest amount of benzophenone among all tested. Dr Craig Downs, an expert on the impacts of sunscreens on marine life, said: “Most of the information (on the two molecules) has come from industry reports so this paper blows all of that up and calls into question all of the industry narratives that octocrylene is safe to be used.” “My big hope is that industry innovates, invests in searching for safer and much more environmentally sustainable ingredients, – because octocrylene is petrochemical-derived – rather than using the tired mantra of manufactured doubt,” he said. He added: “If you want to get serious about managing your carbon footprint, having something that degrades into a carcinogen is just not worth it for for many people.” The study concludes: “Consideration must be given to the responsible regulatory response to prohibit the manufacture and sale of these octocrylene/benzophenone formulated products until industry can prove beyond a reasonable doubt that chronic exposure does not cause harm.” Contacted, Nivea parent company Beiersdorf and L’Oréal had not responded at the time of publication. France’s cosmetics federation, FEBEA, said that given all the “extremely strict rules” by European and French health authorities, “all products and ingredients placed on the market are thus safe for health”. It said the SCCS had recently “reaffirmed the safety of authorised doses” of octocrylene and that everything was done “to ensure the quantities are always below toxicity levels”. Despite the US bans, it also said that “the potentially carcinogenic nature of benzophenone has never been demonstrated”. It said even if one was to apply 0.5mg per day of the molecule (in 18g of sunscreen) it would still amount to “three times less than the maximum tolerated oral dose”. “In any case, these traces of benzophenone have no impact on health,” it said. On the other hand, “skin cancers are among the types that are increasing the most in France” with one in five French people still failing to apply sunscreen despite health warnings.