Ingredient deep-dive

Polyphenylsilsesquioxane: Is It a Microplastic?

Sources reviewedSilicone

Polyphenylsilsesquioxane is a silicone resin. The name alone cannot establish its particle form or microplastics-rule scope, and the CIR linear phenyl-methicone conclusion does not assess this resin.

Shared method updated October 6, 2026. Individual sources reviewed October 6, 2026.

What changed in this reference

Earlier pages inferred a yes/no microplastic verdict from an editorial high/medium/low grouping. Those labels were not measurements or health-risk grades. The shared answer, FAQ and regulation context now distinguish label names from physical particles. This entry also received the individual source review described below.

Polyphenylsilsesquioxane is a polymeric silicone resin with phenyl groups. The Korea Cosmetic Association dictionary lists binding, film formation and opacifying functions. This identity is distinct from Phenyl Trimethicone.

Identity corrections and evidence limits

The universal physical-form and exemption claims are withdrawn. The dictionary supplies identity and functions; it is not regulatory permission or a finished-product safety assessment.

CIR’s 2023 report explicitly excludes this resin after correcting a shared-identity error. This reference reviews nomenclature and source boundaries; a separate comprehensive safety assessment is not claimed.

Reported uses and functions

Binding
Film formation
Opacifying

How the rules depend on the product

European Union

The EU restriction depends on polymer and particle criteria, exclusions and use. Abrasive microbeads have no transition after 17 October 2023. Otherwise, covered rinse-off cosmetics generally transition on 17 October 2027, other leave-on cosmetics on 17 October 2029, and make-up, lip and nail products on 17 October 2035. Microbeads, fragrance encapsulation and rinse-off uses have specific exceptions to those groupings. A name alone cannot establish compliance.

United States

The federal Microbead-Free Waters Act targets intentionally added solid plastic microbeads in rinse-off cosmetics for exfoliating or cleansing. It is not a blanket ban on all polymers or a product safety assessment. Other applicable rules require separate checking.

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Polyphenylsilsesquioxane, common questions

Is Polyphenylsilsesquioxane a microplastic?

Polyphenylsilsesquioxane is a silicone resin. The name alone cannot establish its particle form or microplastics-rule scope, and the CIR linear phenyl-methicone conclusion does not assess this resin.

Does a label match mean Polyphenylsilsesquioxane is banned?

A label match alone cannot determine product compliance. EU context: The EU restriction depends on polymer and particle criteria, exclusions and use. Abrasive microbeads have no transition after 17 October 2023. Otherwise, covered rinse-off cosmetics generally transition on 17 October 2027, other leave-on cosmetics on 17 October 2029, and make-up, lip and nail products on 17 October 2035. Microbeads, fragrance encapsulation and rinse-off uses have specific exceptions to those groupings. A name alone cannot establish compliance. US context: The federal Microbead-Free Waters Act targets intentionally added solid plastic microbeads in rinse-off cosmetics for exfoliating or cleansing. It is not a blanket ban on all polymers or a product safety assessment. Other applicable rules require separate checking. Other substance-specific rules are separate from the microplastic definition; this reference is not a compliance determination.

Can a label show the particle count or health effect?

A label-name match does not measure particles, concentration, exposure or health effects. Polymer identity alone does not establish particle form or legal scope.

Sources and review scope

The Commission guide establishes the shared definition and transition context; CosIng inclusion is not ingredient approval. Label rules do not provide a particle assay. Ingredient-specific sources support the identity and scope stated here, not a tested product or measured health outcome.