Cyclopentasiloxane (D5) and Cyclic Silicones, Explained: What the EU's 0.1% Limit Covers, and the June 2027 Date for Leave-On Products
If you read ingredient lists, you have seen cyclopentasiloxane near the top of primers, some sunscreens and silky serums. It is about to become a European compliance problem, and the reason is not what most social-media posts claim. The legal text behind it, Commission Regulation (EU) 2024/1328, is explicit that the concern is the environment, not a finding about skin. This article walks through what the regulation actually restricts and the dates that apply.
Which three molecules are named
The regulation replaces entry 70 of Annex XVII to REACH and names three cyclic silicones: octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6). On an INCI label they appear as cyclotetrasiloxane, cyclopentasiloxane and cyclohexasiloxane. The entry lists only these three. Dimethicone and other linear silicones are different molecules and are not named in the entry.
The rule: 0.1% by weight
The restriction says the substances may not be placed on the market on their own, as a constituent of other substances, or in mixtures at a concentration equal to or greater than 0.1% by weight. For cosmetics that threshold is the practical test. A product that contains D5 at an impurity-level trace below 0.1% is outside the ban; a product that uses D5 as a carrier at several percent is not.
Wash-off products came first, in 2020
This is a second step, not a first. An earlier measure, Regulation (EU) 2018/35, had already restricted D4 and D5 in wash-off cosmetics, and the new text keeps that date: for D4 and D5 in products that are washed off with water after application, the 0.1% limit has applied since 31 January 2020. Cleansers and rinse-off hair products were reformulated years ago. The 2024 regulation closes the remaining gap, the products that stay on skin.
Leave-on cosmetics: after 6 June 2027
For all cosmetic products other than wash-off ones, the ban applies after 6 June 2027. That includes primers, foundations and BB creams, moisturizers, sunscreens and serums. The general date in the entry is 6 June 2026, but the cosmetics derogation in point 3(b) pushes leave-on products back by one year. If you have seen "June 2026" quoted for makeup or skincare, that is the general date, not the leave-on date.
Why the law says it is doing this
The recitals state that action is needed on a Union-wide basis to address risks to the environment posed by D4, D5 and D6 when they are discharged. D4, D5 and D6 were identified as substances of very high concern because they are very persistent and very bioaccumulative (vPvB); D4 also has persistent, bioaccumulative and toxic (PBT) properties. The Risk Assessment Committee concluded that wide-dispersive uses in cosmetics are the main source of releases. Nothing in that reasoning is a claim that a cream containing D5 harms the person wearing it. It is an emissions argument.
How the transition periods were chosen
The regulation records that the Commission weighed how many products would need reformulating. For non-wash-off cosmetics it chose a three-year deferral, reasoning that for persistent substances a longer transition means more emissions, while also noting the significant reformulation costs. That is why your current products may still list cyclopentasiloxane today, and why brands selling in the EU will be quietly swapping carriers over the next months. Related labelling changes are covered in the EU fragrance allergen article and the phenoxyethanol article, which looks at a limit that does rest on a safety margin.
What this means when you shop
Outside the EU the entry does not apply, so a K-beauty product sold in Korea or the US may still use these silicones; that is a market difference, not a defect. If you shop in the EU, expect reformulated versions of silky textures to feel slightly different. A swap does not make the older version unsafe, and it does not make the new one better; compare textures by trying a small amount. Formulation questions such as which carrier replaces a cyclic silicone are the brand's, and the label-claims article explains why marketing words rarely tell you the underlying chemistry.
The short version
Three named cyclic silicones, a 0.1% by weight limit, wash-off products already covered since 31 January 2020, leave-on cosmetics covered after 6 June 2027, and a stated environmental rationale. Check the dates against the text of Regulation (EU) 2024/1328 and the current Annex XVII entry 70 on EUR-Lex before relying on them for a compliance decision.
This article is general education, not medical advice; patch-test any new product on a small area first and consult a dermatologist about persistent skin concerns.
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