Safety assessment of cyclomethicone, cyclotetrasiloxane, cyclopentasiloxane, cyclohexasiloxane, and cycloheptasiloxane

Int J Toxicol. 2011 Dec;30(6 Suppl):149S-227S. doi: 10.1177/1091581811428184.


Cyclomethicone (mixture) and the specific chain length cyclic siloxanes (n = 4-7) reviewed in this safety assessment are cyclic dimethyl polysiloxane compounds. These ingredients have the skin/hair conditioning agent function in common. Minimal percutaneous absorption was associated with these ingredients and the available data do not suggest skin irritation or sensitization potential. Also, it is not likely that dermal exposure to these ingredients from cosmetics would cause significant systemic exposure. The Cosmetic Ingredient Review Expert Panel concluded that these ingredients are safe in the present practices of use and concentration.

Publication types

  • Review

MeSH terms

  • Animals
  • Consumer Product Safety
  • Cosmetics / pharmacokinetics
  • Cosmetics / toxicity*
  • Humans
  • Risk Assessment
  • Siloxanes / pharmacokinetics
  • Siloxanes / toxicity*


  • Cosmetics
  • Siloxanes