Polymethylsilsesquioxane
Also known as PMSSQ, Polymethylsilsesquioxane resin, Methyl silsesquioxane polymer
“CIR Expert Panel says: safe as used in cosmetics.”
Polymethylsilsesquioxane (PMSSQ; CAS 68554-70-1) is a silsesquioxane-class silicone resin used in cosmetics primarily as a mattifying and blurring agent, imparting a soft-focus effect and smooth skin feel. The CIR Expert Panel assessed PMSSQ in its December 2017 final report and found it safe as used in cosmetic formulations (Finding=S, no concentration conditions). No ingredient-specific PubMed safety studies were identified; the available literature covers materials science applications only. The chemically inert, crosslinked polymer structure confers low dermal penetration potential.
Mattifying and optical blurring agent; imparts soft-focus effect in skin and color cosmetics
Chemically inert silsesquioxane resin with low dermal penetration potential
CIR Expert Panel found safe as used in cosmetics (Final report 12/2017)
Non-volatile; does not present inhalation exposure concerns in non-aerosol applications
CIR Quick Reference Table (12/2017, revised 07/2018) — Polymethylsilsesquioxane row: Finding=S, Citation=Final report 12/2017 available f…
“Polymethylsilsesquioxane | S | | Final report 12/2017 available from CIR”— QRT-122017revised072018.pdf, p. 107