Cyclotetrasiloxane
Explained
This ingredient is a small silicone made to be silky and weightless. It works as an emollient and solvent for heavier pigments/silicones as well.
According to the CIR Expert Panel, this ingredient is considered gentle and doesn't penetrate deeply into skin.
Regulations
The EU and UK have banned this ingredient in cosmetics since 2020. A separate EU REACH (Registration, Evaluation, Authorisation, and Restriction of Chemicals) rule caps D4 as a trace impurity at under 0.1% in any cosmetic.
- It is permitted in South Korea with concentration limits
- It is permitted in cosmetics in the US, Canada, and Australia.
In September of 2025, the US EPA's draft TSCA risk evaluation that came out in September 2025 preliminarily found D4 poses "unreasonable risk to human health and the environment". This could lead to restrictions in the next year or so.
See all 224 products with Cyclotetrasiloxane
