Cetyl Dimethicone is a silicone-based compound derived from dimethylsiloxane and cetyl alcohol. It is used in cosmetic and personal care products for its excellent emollient and film-forming properties. This ingredient imparts a smooth and silky texture to products, enhancing their application and feel on the skin or hair.

Chemical Composition and Structure

• Chemical Composition: Cetyl Dimethicone is composed of dimethylsiloxane, a silicone that forms a three-dimensional network, and cetyl alcohol. The result is a long-chain silicone with excellent emollient properties.

• Structure: The structure includes a chain of dimethylsiloxane with cetyl groups attached. This gives the compound its ability to create a protective barrier on the skin and hair while enhancing the tactile sensation.

Physical Properties

• Appearance: Typically a clear, viscous liquid or an opaque paste, depending on the concentration and formulation.
• Solubility: Insoluble in water but soluble in organic solvents and easily dispersible in cosmetic products.
• pH: Stable across a wide range of pH values, making it suitable for various types of products.

Production Process

1. Silicone Polymerization: Dimethylsiloxane is polymerized to create a silicone base.
2. Addition of Cetyl Alcohol: Cetyl alcohol is combined with the silicone to form Cetyl Dimethicone.
3. Purification: The compound is purified to ensure it is safe for use and free from impurities.
4. Formulation: It is incorporated into cosmetic formulations to enhance product consistency and emollient properties.

Applications

• Medical: Not commonly used in medical applications.
• Cosmetics: Used in a variety of cosmetic products, including creams, lotions, shampoos, and conditioners. Provides a silky feel and improves the spreadability of the product. Helps reduce frizz and enhances the overall appearance of hair.

Cosmetics

Skin conditioning agent - Emollient. Emollients have the characteristic of enhancing the skin barrier through a source of exogenous lipids that adhere to the skin, improving barrier properties by filling gaps in intercorneocyte clusters to improve hydration while protecting against inflammation. In practice, they have the ability to create a barrier that prevents transepidermal water loss. Emollients are described as degreasing or refreshing additives that improve the lipid content of the upper layers of the skin by preventing degreasing and drying of the skin. The problem with emollients is that many have a strong lipophilic character and are identified as occlusive ingredients; they are oily and fatty materials that remain on the skin surface and reduce transepidermal water loss. In cosmetics, emollients and moisturisers are often considered synonymous with humectants and occlusives.

CAS: 191044-49-2

• Food: Not used in food products.

Environmental and Safety Considerations

Generally regarded as safe for topical application (1). However, like all silicones, it should be used in accordance with established guidelines to avoid potential allergic reactions or skin irritations. People with sensitive skin or allergies should exercise caution. It is important to ensure that the ingredient is sustainably sourced and free from harmful chemicals.

References__________________________________________________________________________

(1) Nair B; Cosmetic Ingredients Review Expert Panel. Final report on the safety assessment of stearoxy dimethicone, dimethicone, methicone, amino bispropyl dimethicone, aminopropyl dimethicone, amodimethicone, amodimethicone hydroxystearate, behenoxy dimethicone, C24-28 alkyl methicone, C30-45 alkyl methicone, C30-45 alkyl dimethicone, cetearyl methicone, cetyl dimethicone, dimethoxysilyl ethylenediaminopropyl dimethicone, hexyl methicone, hydroxypropyldimethicone, stearamidopropyl dimethicone, stearyl dimethicone, stearyl methicone, and vinyldimethicone. Int J Toxicol. 2003;22 Suppl 2:11-35. PMID: 14555417.

Abstract. Dimethicone is a fluid mixture of fully methylated linear siloxane polymers end-blocked with trimethylsiloxy units. Methicone is a linear monomethyl polysiloxane. The other dimethicones and methicones covered in this review are siloxane polymers of Dimethicone and Methicone. Most of these ingredients function as conditioning agents in cosmetic formulations at current concentrations of use of < or =15%. Clinical and animal absorption studies reported that Dimethicone was not absorbed following oral or dermal exposure. Dimethicone, Methicone, and Vinyldimethicone were not acutely toxic following oral exposure. No adverse reactions were found in rabbits following short-term dermal dosing with 6% to 79% Dimethicone, yet adverse effects were noted with a hand cream formulation containing 1% Dimethicone, suggesting something else in the preparation was toxic. Mice and rats were dosed for 90 days with up to 10% Dimethicone without adverse effect. Dimethicone did not produce adverse effects in acute and short-term inhalation-route studies, Methicone and Vinyldimethicone were negative in acute exposure studies using rats, but Hexyl Methicone was toxic to rats at 5 mg/L delivered in small particle (mean diameter of 0.29 micro) aerosols. Most dermal irritation studies using rabbits classified Dimethicone as a minimal irritant. Dimethicone (tested undiluted and at 79%) was not a sensitizer in four assays using mice and guinea pigs. It was not a sensitizer at 5.0% in a clinical repeated insult patch test using 83 panelists. Most ocular irritation studies using rabbits classified Dimethicone as a mild to minimal irritant. Dimethicone was tested in numerous oral-dose (using rats) and dermal-dose (using rats, rabbits, and monkeys) reproductive and developmental toxicity studies. In a few studies, treated males had significantly decreased body weight and/or decreased testes or seminal vesicles weights. No treatment-related adverse findings were noted in dosed pregnant females or fetuses. Dimethicone was negative in all genotoxicity assays. It was negative in both an oral (tested at 91%) and dermal (tested at an unknown concentration) dose carcinogenicity assay using mice. The Cosmetic Ingredient Review (CIR) Expert Panel considered it unlikely that any of these polymers would be significantly absorbed into the skin due to their large molecular weight. Although adverse effects were noted in one inhalation study with small aerosol particles, the expected particle sizes for cosmetic products would primarily be in the range of 60 to 80 micro, and less than 1% would be under 10 micro, which is an upper limit for respirable particles. Overall, the safety test data support the safety of these ingredients at the concentrations they are known to be used in cosmetic formulations. Accordingly, the CIR Expert Panel was of the opinion that Stearoxy Dimethicone, Dimethicone, Methicone, Amino Bispropyl Dimethicone, Aminopropyl Dimethicone, Amodimethicone, Amodimethicone Hydroxystearate, Behenoxy Dimethicone, C24-28 Alkyl Methicone, C30-45 Alkyl Methicone, C30-45 Alkyl Dimethicone, Cetearyl Methicone, Cetyl Dimethicone, Dimethoxysilyl Ethylenediaminopropyl Dimethicone, Hexyl Methicone, Hydroxypropyldimethicone, Stearamidopropyl Dimethicone, Stearyl Dimethicone, Stearyl Methicone, and Vinyldimethicone are safe as used in cosmetic formulations.