# TRIMETHYLPENTYL POLYSILSESQUIOXANE

URL: https://app.greenveil.ai/ingredients/ingredient_dtxsid_dtxsid101075702
Categories: beauty
Functions: Nail conditioning
Identifier: DTXSID101075702

> TRIMETHYLPENTYL POLYSILSESQUIOXANE: Used in cosmetics as a nail conditioning agent. EPA DSSTox provides the canonical identifier, structure, and synonym profile for this chemical. Compiled from 2 published data sources.

## Safety assessment

- Chemical concern: not yet assessed
- Is it a concern? We haven't assessed a concern score for this ingredient yet. It is listed for cosmetic use in the EU.
- Rationale: EPA DSSTox provides the canonical identifier, structure, and synonym profile for this chemical.

## Regulatory status

- EU: Active — Trimethylpentyl Polysilsesquioxane is a resinous material composed of a mixture of three-dimensional siloxane polymers and oligomers with cage structures. For the oligomers, each silicon atom in the polysilsesquioxane is connected via oxygen atoms to three other silicon atoms and can be represented by the empirical formulation RSiO3/2 where R represents the trimethylpentyl group. For the larger polymeric polysilsesquioxanes, some of the silicon atoms are not connected to other silicon atoms and instead have a silanol (SiOH) group. Trimethylpentyl Polysilsesquioxane is prepared by the hydrolysis and condensation of 2,4,4-trimethylpentyl trimethoxysilane

## Expert safety opinions

- SCCS (EU Scientific Committee on Consumer Safety): no opinion on file.
- CIR (Cosmetic Ingredient Review (US expert panel)): no opinion on file.

## Data sources

- CosIng (updated 2026-09-23): https://ec.europa.eu/growth/tools-databases/cosing/details/93229
- EPA DSSTox Identifiers (updated 2025-12-29): https://epa.figshare.com/articles/dataset/Chemistry_Dashboard_Data_DSSTox_Identifiers_Mapped_to_CAS_Numbers_and_Names/5588566

_Assessed by Greenveil._