EU's June 6 D5 and D6 Ban Will Reshape Skincare Globally

The European Union's restriction on the two cyclic silicones most responsible for the silky, fast-spreading feel of modern skincare takes effect on June 6, 2026. From that date, decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) cannot be placed on the EU market at concentrations of 0.1% by weight or above in cosmetics. The deadline closes a multi-year regulatory process that began with environmental hazard assessments and ends with one of the largest forced reformulation events in cosmetic chemistry this decade. **Key Takeaways** - Commission Regulation (EU) 2024/1328 restricts decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) to under 0.1% by weight in cosmetics placed on the EU market from June 6, 2026, with the same restriction for leave-on products from June 6, 2027. - ECHA classifies D5 as very persistent and very bioaccumulative (vPvB) and D6 as persistent, bioaccumulative and toxic (PBT); cosmetics were identified as the main release pathway into water and air. - At NYSCC Suppliers' Day on May 19-20, 2026, Pilot Chemical, Thomas Swan, and Wacker showcased branched-hydrocarbon, ester-based, and bio-based replacements positioned for direct substitution. - Multinational skincare brands generally reformulate to one global standard, so the EU rule will drive INCI changes on U.S. and Asian shelves within 12 to 24 months. The European Commission adopted the restriction on May 16, 2024, giving the industry just over two years to clear and reformulate non-compliant stock. The European Commission estimates the rule will reduce environmental emissions of D4, D5, and D6 by up to 90%, according to its restriction dossier filed under REACH Annex XVII. ## How D5 and D6 Built the Modern Sensory Profile of Skincare Cyclopentasiloxane and cyclohexasiloxane were the workhorses of the silicone-driven skincare aesthetic that has dominated formulation since the late 1990s. Both are low-viscosity volatile silicones that flash off the skin after application, leaving behind a smooth slip without an oily residue. Formulators used them as carriers for actives, as primers under foundation, as anti-foam in sunscreens, and as the dominant sensory note in nearly every "silky" serum. INCI listings typically read "cyclopentasiloxane" or "cyclomethicone," the umbrella term for cyclic siloxanes including D4, D5, and D6. Two regulatory phases preceded the June 6 deadline. Commission Regulation (EU) 2018/35 restricted D4 and D5 in wash-off cosmetics from January 31, 2020, at the same 0.1% threshold. D4 (octamethylcyclotetrasiloxane), which is suspected of endocrine-disrupting effects, had already been removed from cosmetics in 2022. The 2024 restriction closes the loop by capturing D5 and D6 across both wash-off and leave-on cosmetics, including serums, primers, sunscreens, and hair conditioners. These are the categories where the two molecules deliver their most distinctive feel. The 2027 deadline for leave-on cosmetics is the inflection point most relevant to skincare consumers. Wash-off products have been reformulating for six years. Serums, moisturizers, sunscreens, and primers are reformulating now. ## Why Did ECHA Restrict D5 and D6 Rather Than Limit Them by Use? ECHA's restriction is grounded in environmental persistence rather than direct toxicity to humans. D5 is classified as very persistent and very bioaccumulative (vPvB) and D6 as persistent, bioaccumulative and toxic (PBT) under REACH. Once released, the molecules resist breakdown, accumulate in sediments and biota, and have been detected in sewage sludge, soil, and surface water. The European Commission's Risk Assessment Committee identified cosmetic products, particularly wash-off and rinse-off applications, as the main release source. Hair conditioners, anti-perspirants, and rinse-off cleansers were restricted first in 2018 because those products send the largest volume of cyclic siloxane directly to wastewater. Leave-on cosmetics release the substances primarily through volatilization, contributing to long-range atmospheric transport that has placed D5 in Arctic air samples thousands of kilometers from any point of use. The cosmetic chemistry equivalent of the [EU's broader 15-substance CMR ban earlier this year](https://skincareful.care/science/eu-bans-15-cmr-substances-cosmetics-2026/) is now in motion for silicones. ## What Will Replace D5 and D6 in Reformulated Products? The reformulation question dominated the floor at NYSCC Suppliers' Day on May 19 and 20, 2026, at the Javits Center in New York. Pilot Chemical presented UpSyCal BA17 and BA14, branched-hydrocarbon emollients designed to match the volatile, fast-spreading profile of D5 in serums and sunscreens. Thomas Swan presented CasEmol, a drop-in cyclosiloxane replacement aimed at primers and other sensory-driven leave-on formulas. Wacker presented bio-based emollients spanning hair care and skin care applications, drawn from fermentation-derived feedstocks. The replacement universe falls into three chemistry families. Branched hydrocarbons, including the C13-15 alkanes and isododecane, replicate the volatility and slip of D5 most directly and have become the early default for sunscreens. Esters such as coco-caprylate/caprate and dicaprylyl carbonate substitute well in skin care leave-ons, though with a slightly heavier afterfeel. Low-viscosity linear silicones such as dimethicone fluid satisfy the regulatory threshold but change the breakdown profile entirely, since linear silicones are not classified as PBT or vPvB. INCI deck changes will become visible to consumers over the next 12 to 24 months. "Cyclopentasiloxane" and "cyclomethicone" will disappear from leave-on products, replaced by the alternatives above. The substitutes do not match D5 and D6 exactly on every sensory or stability axis, so reformulated products may feel measurably different. For consumers reading [ingredient labels closely](https://skincareful.care/science/how-to-read-sunscreen-label-uva-pf-ppd-decoded-2026/), the reformulation wave offers a rare natural experiment in cosmetic chemistry. Two versions of the same well-loved product, separated by an INCI change at one position in the deck, will appear on shelves over the coming year. The full text of Commission Regulation (EU) 2024/1328 is published in the EU's Official Journal. ECHA's cyclosiloxanes hot-topics page hosts the underlying hazard dossiers, and the NYSCC Suppliers' Day 2026 program lists the supplier showcases referenced above. ```json { "@context": "https://schema.org", "@type": "NewsArticle", "headline": "EU's June 6 D5 and D6 Ban Will Reshape Skincare Globally", "description": "On June 6, 2026, the EU restricts D5 and D6 silicones in cosmetics to under 0.1%. Here's what changes, why ECHA acted, and the replacement chemistries.", "datePublished": "2026-05-21T18:00:00-04:00", "dateModified": "2026-05-21T18:00:00-04:00", "author": { "@type": "Person", "name": "SkinCareful News", "url": "https://skincareful.care/author/skincareful-news/" }, "publisher": { "@type": "Organization", "name": "SkinCareful", "url": "https://skincareful.care", "logo": { "@type": "ImageObject", "url": "https://skincareful.care/logo.png" } }, "image": "https://skincareful.care/images/articles/eu-cyclosiloxane-d5-d6-ban-june-2026.jpg", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://skincareful.care/science/eu-cyclosiloxane-d5-d6-ban-june-2026/" } } ```