Ingredient deep-dive
Cyclotetrasiloxane (D4): Is It a Microplastic?
Cyclic silicone with the strictest regulatory status of the group. Not a microplastic, but classified in the EU as a substance of very high concern for persistence, bioaccumulation and toxicity.
Where it appears
- Legacy hair and skin formulas
- Some antiperspirants
Regulatory status (2026)
European Union
Substance of Very High Concern; restricted to 0.1% in cosmetics.
United States
No federal restriction.
Cleaner alternatives
- Squalane
- Plant oils
- Silicone-free serums
Use the app
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Download on the App StoreCyclotetrasiloxane (D4), common questions
Is Cyclotetrasiloxane (D4) a microplastic?
Is Cyclotetrasiloxane (D4) banned?
What can I use instead of Cyclotetrasiloxane (D4)?
What products contain Cyclotetrasiloxane (D4)?
Related ingredients
Dimethicone
Silicone · Medium concern
Silicone polymer (polydimethylsiloxane). Not the same as solid microplastic but classed as a synthetic polymer; EU is consulting on tighter limits.
Read moreCyclomethicone / Cyclopentasiloxane
Silicone · Medium concern
Cyclic siloxanes. D4 and D5 variants are EU-restricted in rinse-off products.
Read moreTrimethicone / Phenyl Trimethicone
Silicone · Low concern
Silicone polymer variant used for slip and shine.
Read morePolysilicone-X
Silicone · Medium concern
Synthetic silicone polymer family used as film-formers in long-wear makeup.
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