The European Union (EU) will soon complete its restriction of cyclic silicones D4, D5, and D6 in cosmetics. As the final phase-out deadline approaches, it indicates a wider shift against environmentally problematic ingredients.
Cyclic silicones (silicone materials formed by repeating and closed-loop units of silicone and oxygen in a cyclic structure) have been widely used as texture improvers in beauty and personal care products for decades. But in recent years, the EU has identified these materials as persistent and bioaccumulative in the environment and issued restrictions across various categories.
Since 2020, octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) have been banned in rinse-off cosmetics over environmental concerns. And in 2024, the European Commission widened the ban to include dodecamethylcyclohexasiloxane (D6) in rinse-off cosmetics from June 2026, and all three cyclic silicones in leave-on cosmetics from June 2027.
The market-wide restrictions are detailed in the European Commission Regulation (EU) 2024/1328 that amends Annex XVII of the EU Registration, Evaluation, Authorisation and Restriction of Chemicals ([REACH)] Regulation EC 1907/2006.
“There is a surface story here about the particular group of ingredients, and there's a bigger underlying story about the direction of travel, which I think is actually, possibly, more interesting,” said John Chave, Director -General of trade association Cosmetics Europe.
The direction of travel, Chave told BeautyMatter, is that ingredients in Europe are no longer being challenged and restricted on human health grounds but are increasingly being restricted on environmental grounds. And this is “a significant story,” he said, given the magnitude of ingredients used in beauty and personal care formulas that could be assessed on environmental grounds.
According to the Director -General, it is fair to anticipate that ingredient restrictions based on environmental impact will continue and perhaps even widen, as the EU Cosmetics Product Regulation (CPR) increasingly assesses ingredients on environmental grounds and the EU REACH Regulation continues to investigate the environmental impact of chemicals.
“The regulatory door has been opened wider to address ingredients on environmental grounds than in the past, and I think there is just more wider awareness in general,” he said.
The EU has already taken a strong stance against microplastics in cosmetics, for example, with 2027, 2029, and 2035 compliance deadlines also approaching—–a regulatory move that can be considered the trailblazer within this wider eco shift, Chave said.
“Often these conversations come back to cosmetics. It hits cosmetics hard because of the intricate formulas we have, the large-scale regulation that needs to be done, and often there aren't clear and obvious alternatives.”
Cyclic silicones have been used in a significant number of beauty and personal care formulations over the years, from makeup and hair products through to antiperspirants, body creams, and more, providing enhanced textures, binding, and functional properties that consumers and industry have long become accustomed to.
“Cyclic silicones have some really unique properties that other chemistries can't really match,” explained Kelly Dobos, US-based iIndependent Consultant Cosmetic Chemist and Adjunct Professor in the Cosmetic Science Program at the University of Cincinnati. “Exceptionally low surface tension allows them to spread quickly, and they quickly evaporate, making them excellent carriers for heavier functional ingredients. Replacing these ingredients can require a reset of performance expectations,” Dobos told BeautyMatter.
In particular, replacing cyclic silicones in leave-on cosmetics—–the category impacted by the final phase of the ban next year—–is even more difficult, she said. “In high-performance and prestige products, these ingredients might be hard to replace without also resetting consumer expectations.”
Today, plenty of D4, D5, and D6 alternatives can be found on the market, though the industry agrees that none offer perfect replacements, yet. But Dobos said a lot of hard work has gone into developing suitable alternatives in recent years and remains ongoing. “There's been a lot of effort on the part of raw material suppliers to bring innovative chemistries to the market to try and replace cyclic silicones. And they are doing a lot of the legwork in proving comparative data, which is helpful when assessing options.”
The phased approach to these restrictions, Dobosshe said, has been “really helpful for the cosmetics industry,” given how complex replacing cyclic silicones is and that even the simplest reformulation takes upwards of six months to a year.
“Reformulation isn't easy. It takes raw material screening, stability and packing compatibility testing, new safety and regulatory reviews, performance and claims testing, and then scale-up and manufacturing trials. There's really a lot to accomplish,” Dobos said. “When regulators allow for timelines that reflect that complexity, it gives manufacturers time to work strategically.”
Dr. Barbara Brockway, Scientific Advisor in Cosmetics &and Personal Care and owner of Barbara Brockway Consulting, agreed that the restrictions on D4, D5, and D6 certainly “present a real challenge.”
“These materials do not lend themselves to straightforward substitution,” Brockway said. Reformulating or creating new products without cyclic silicones while maintaining the same sensual qualities requires skill, she said, a skill that should be identified and invested in.
“Thinking positively, the industry's most talented formulators have an opportunity to demonstrate exactly why they matter. So, back your best people, give them the latitude to innovate, and let them rise to the challenge,” the expert said.
Dobos agreed: “While there are certainly challenges in replacing cyclic silicones, this is also an opportunity to innovate,; to make new discoveries. Replacing cyclic silicones is not impossible but it does require creativity, time, and even a willingness to evolve formulations, not just swap out ingredients.”
It will be important for the industry to consider working with an array of new ingredients but also blends of alternative ingredients too, she said, “to optimize performance as needed.”
Chave said it is, of course, disappointing for the industry when a good technology or group of ingredients that deliver high levels of functionality is ultimately restricted. But, he said, the industry is “not arguing in favor of environmentally problematic ingredients.”
“We're a responsible industry, we're committed to sustainability, and we accept the process,” he said. “... Of course, we will defend ingredients where we think they can be defended on scientific grounds, and where we know they can't be, the industry needs to move on and find alternatives.”
Looking ahead, the Director -General said the broader lesson for the industry is that there will likely be further scrutiny of ingredients and additional challenges from REACH, particularly regarding persistence and bioaccumulation in the environment. Restrictions may also expand beyond Europe, as many other regions tend to follow suit when the European Commission makes the first move to restrict an ingredient or technology.
“Watch this space for future restrictions,” he said. “I think the industry probably needs to reflect on how exactly it prepares and anticipates for the possibility of more restrictions coming through the pipeline in the future.”
One cosmetics regulation and formulation expert, who preferred to remain anonymous, said the science behind the ban on cyclic silicones is “slightly flawed,” raising concerns about potential future bans.
“The testing is mandated within the REACH regulations;, however, it takes no account of the volatility of the substances, as the mandated environmental testing is in a closed system, so it does not present a proper in-use scenario,” she said. “... As a cosmetic chemist, I want to develop products that are effective and liked by the consumers. But these products must also, of course, be safe for the consumer and the wider environment. What I would like is testing to reflect actual use. We are seeing ingredients banned because they have shown in some testing conditions to be an environmental hazard, but if that testing doesn't represent how the ingredients actually behave in the environment, then we may be banning ingredients unnecessarily.”