FORMULATING


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Practical alternatives for moving on from cyclic silicones


Elizabeth Guest - Thomas Swan & Co


As regulatory pressure intensifies across the EU and UK, the role of cyclic silicones in cosmetics is undergoing rapid reassessment. Materials such as D4 (octamethylcyclotetrasiloxane), D5 (decamethylcyclopentasiloxane) and D6 (dodecamethylcyclohexasiloxane) have long shaped the sensorial character of formulations, offering slip, spreadability and the familiar light, silky feel consumers expect. But with growing environmental concerns around persistence and bioaccumulation, formulators are increasingly seeking alternatives that deliver comparable performance without regulatory complexity. As EU/UK restrictions tighten on D4, D5 and


D6, reformulation has shifted from ‘sometime soon’ to ‘right now’ for many brands. This feature explains what cyclic silicones do in formulas, what changes when you remove them, and how biodegradable, linear paraffinic emollients can be used to rebuild the sensory profiles consumers expect with longer term regulatory confidence.


The regulatory context: what changes when Since 2019, cyclic silicones have been closely watched by regulatory bodies. D4 was one of the first to be restricted and is prohibited for cosmetic use in the EU, with only unavoidable traces (≤0.1%) permitted. This is due to its Carcinogenic, Mutagenic or Reprotoxic (CMR) status, which automatically moves it to Annex II of Regulation (EC) No 1223/2009. Due to their classification of being very


Persistent and very Bioaccumulative (vPvB), restrictions on D5 and D6 have also tightened significantly; D5 remains limited to 0.1% in rinse-off formats (as of January 2020), and by 2027 both D5 and D6 will be capped at 0.1% across all leave- on and rinse-off applications. For many brands, these shifts mean that reformulation is no longer optional — it is a strategic and operational priority. In the UK, wash-off restrictions on D4/D5


mirror the EU regime; further action on leave-on applications has been under review within the UK


EU TIMELINE AT A GLANCE


■ D4: Prohibited in EU cosmetics; only ≤0.1% technically unavoidable traces permitted. ■ D5 (rinse‑off): ≤0.1% since 31 Jan 2020. ■ D5 (leave-on) & D6 (all formats): ≤0.1% by 6 Jun 2027 (EU)


REACH process. For EU-bound products, the 2027 deadlines apply as stated above. By 6 June 2027, both D5 and D6 face a 0.1%


limit across all cosmetic formats—leaving no room for the old ‘rinse-off vs leave-on’ distinction.


What cyclic silicones actually do in formulations (and why it is hard to replace) From a formulator’s perspective, the appeal of cyclosiloxanes is not just their ‘silky’ aesthetic, it is the way volatility, low surface tension and shear-dependent flow come together to create quick-break, long glide and a clean after-feel in formulations. In practical terms, the advantages of cyclic silicones are as follows.


Volatility & dry‑down kinetics, offering perceptual cleanliness Even in richer formulas, alternatives need to recreate the clean, quick-break feel associated with silicones that leave the after-feel ‘dry’ rather than greasy.


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Spread & slip Low surface tension helps lift the drag you sometimes feel with heavier oils. It is also why pigments wet easily and why colour cosmetics level well. These cyclic silicones can help carry other materials to fill pores and even create a blurring, soft focus, effect themselves, before evaporating off the skin’s surface.


Compatibility & stability They integrate smoothly with many materials, and their rheological neutrality often simplifies emulsion tuning. They are chemically stable, including to oxidation and over a wide pH range. Replacement drop-in materials must therefore ideally integrate well with colour systems, UV filters and high active content formulations across both emulsion and anhydrous formats. Remove them and a few things tend to happen, dry-down slows, spread shortens, and cushion can collapse, unless you redesign the oil phase with intent. None of this is a barrier, it


July 2026 PERSONAL CARE MAGAZINE


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