Cyclopentasiloxane and Dimethiconol

CAS Number:

541-02-6 (for Cyclopentasiloxane) ; 70131-67-8 (for Dimethiconol)

INCI Name:

Cyclopentasiloxane (and) Dimethiconol

Molecular Formula:

 C10H30O5Si5 (for Cyclopentasiloxane); (C?H?OSi)? (for Dimethiconol)

Other Names:

Blend of D5 and silicone gum; available under trade names such as XIAMETER™ PMX-1501 Fluid (Dow), MIRASIL™ C-DML (Elkem), BELSIL® CM 1000 (Wacker), AC-1202 (ANCHORChem), and others

Uses:

This blend combines a volatile silicone carrier (Cyclopentasiloxane) with a high-viscosity silicone polymer (Dimethiconol). When applied, the volatile Cyclopentasiloxane evaporates, leaving a thin, substantive, and non-greasy film of Dimethiconol on the skin or hair . This technology is used across a wide range of personal care applications:

· Skin Care & Sun Care: Imparts a smooth, dry, velvety feel to the skin. It enhances the water resistance and longevity (substantivity) of sunscreens and other active ingredients in moisturizers, creams, and lotions .

· Hair Care: Provides exceptional conditioning benefits. It confers anti-static properties, adds gloss, and leaves hair feeling soft and silky. It also helps with wet and dry combing and can provide a split-end repair effect .

· Color Cosmetics: Improves the application, spreadability, and skin feel of foundations and other makeup products .

· Antiperspirants & Deodorants: Contributes to a smooth, dry application and helps reduce tackiness Origin

This product is a manufactured synthetic blend. It is composed of two silicone polymers derived from silica .

· Cyclopentasiloxane (D5): A cyclic, volatile silicone that acts as a carrier and spreading agent .

· Dimethiconol: A high molecular weight, linear silicone polymer with terminal hydroxyl groups, providing film-forming and conditioning properties .

The blend is designed to offer a specific ratio, often containing 12-15% Dimethiconol in Cyclopentasiloxane, resulting in a gum-like consistency that is easy to handle.

What does this blend  do in a formulation?

• Film Former: Leaves a durable, water-resistant yet breathable protective barrier on the skin and hair
• Emollient & Conditioning Agent: Softens and smooths the skin (emollient) and provides a silky, conditioned feel to hair .
• Substantivity Enhancer: Increases the long-lasting effect and fixation of other active ingredients .
• Spreading Agent: The volatile carrier ensures even distribution of the film-forming polymer and other ingredients .
• Water Resistance: Improves the water-resistant properties of products like sunscreens .
• Gloss Agent: Adds shine to hair .

Safety Profile (Critical):

· Health & Safety: Both components are considered safe for topical use at current concentrations by expert panels like the Cosmetic Ingredient Review (CIR) . Dimethiconol is a large molecule that does not penetrate the skin and has a very low health risk rating .

· Environmental Concerns (Critical): There are significant environmental concerns associated with the Cyclopentasiloxane (D5) component:

  · It is not readily biodegradable .

  · It has been identified as a Substance of Very High Concern (SVHC) in some regions due to its persistent and bioaccumulative properties .

  · Due to its negative environmental impact, its use in rinse-off cosmetic products is restricted to a maximum concentration of 0.1% in the European Union .

  · Many "clean beauty" retailers and brands (e.g., Sephora, Credo) restrict or prohibit the use of Cyclopentasiloxane in products .

· Biodegradability: The Dimethiconol component is also not readily biodegradable .

Technical profile: