As one of the foundational raw materials in the personal care industry, dimethicone plays an important role in skincare, hair care, and color cosmetics, owing to its stable chemical properties and excellent skin-feel modulation capabilities. Different viscosity grades correspond to different functional positions, allowing formulators to flexibly select products based on specific requirements.

Viscosity Grading and Application Mapping

Dimethicone is classified into multiple grades based on kinematic viscosity, ranging from low-viscosity 5 cSt to high-viscosity 1000 cSt. Low-viscosity products (5–20 cSt) exhibit higher volatility and are commonly used in sunscreens and setting sprays requiring a lightweight feel—they evaporate quickly after application, reducing sticky residue. Medium-viscosity products (50–100 cSt) are the most commonly used type in creams and lotions, forming a breathable film on the skin surface that reduces moisture loss without causing a heavy sensation. High-viscosity products (above 350 cSt) are more commonly found in hair oils, massage oils, and similar products, providing long-lasting smoothness and gloss.

Functional Roles in Skincare

In face cream and lotion formulations, the addition ratio of dimethicone typically ranges from 1% to 5%. Its main functions include: first, improving spreadability during application and reducing the heavy feel imparted by oils in the formulation; second, enhancing product gloss and texture, giving the cream a fine, smooth visual and tactile appearance; and third, acting as an occlusive agent to assist moisture retention by reducing transepidermal water loss (TEWL). In sunscreens, dimethicone also helps uniformly disperse physical UV filters (such as titanium dioxide and zinc oxide) in the formulation, improving spreadability during application and reducing the "whitening" effect.

Performance in Hair Care Products

Dimethicone addition levels in shampoos generally range from 0.5% to 2%, primarily depositing on the hair surface to fill cuticle gaps, reducing friction during wet combing, and minimizing breakage and split ends. In conditioners and hair masks, addition levels can increase to 2%–5%, forming a more durable protective film after rinsing to impart smoothness and gloss to dry hair. Test data show that after silicone-containing conditioner treatment, wet combing force can be reduced by 40%–60%, while dry hair gloss increases by approximately 15%–20%.

Formulation Synergy and Compatibility

Dimethicone exhibits good compatibility with most commonly used cosmetic raw materials. In emulsified systems, the addition method and ratio should be adjusted based on the emulsifier type (O/W or W/O) to avoid destabilizing the system. When combined with plant oils, it balances the oxidative stability and skin feel of natural oils, extending product shelf life. In formulations containing active ingredients (such as niacinamide or vitamin C), the dimethicone film can slow the release rate of active components, to some extent improving formulation mildness.

Industry Standards and Development Directions

As a cosmetic raw material, the production and use of dimethicone must comply with the relevant requirements of the "Safety and Technical Standards for Cosmetics." In recent years, low-cyclic silicone oils (with D4/D5/D6 content below specified limits) have become the mainstream choice for premium products, aligning with regulatory trends on cyclic siloxanes in regions such as the EU. The development of water-soluble silicones (polyether-modified silicones) also provides alternative options for "silicone-free" concept products, improving rinseability while maintaining smoothing effects.

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