Polydimethylsiloxane (PDMS) is one of the most common silicone oil ingredients in skin care products. It is widely used in skin care products, cosmetics and pharmaceutical excipients due to its unique chemical properties and multifunctionality. Its role in skin care is mainly reflected in the following aspects:
1. Occlusive moisturizing: forming a breathable protective film
Polydimethylsiloxane has low surface tension and high hydrophobicity, and can form a thin, breathable protective film on the skin surface. This film can reduce the evaporation of skin moisture (transepidermal water loss, TEWL), enhance the moisturizing effect, and will not completely block the pores. It is suitable for sensitive or dry skin. Compared with other occlusive ingredients (such as petrolatum), it feels lighter on the skin and is not easy to produce a sticky feeling.
2. Soft and smooth: Improve product texture
As a typical "silicone elastomer", it can fill the tiny bumps on the skin surface, instantly smooth the skin texture, and make the skin feel soft and delicate. This feature is often used in primers, sunscreens and foundations to help subsequent makeup to fit better and reduce powder sticking. At the same time, it can also reduce the viscosity of the skin care products themselves and improve ductility.
3. Auxiliary repair: barrier protection and wound care
In medical dressings or repair products, polydimethylsiloxane can reduce external stimulation (such as friction, bacterial contact) through physical coverage, creating a stable repair environment for the skin. Studies have shown that scar gels containing silicone can improve scar hyperplasia, and its mechanism may be related to regulating the hydration of the stratum corneum and inhibiting the excessive proliferation of fibroblasts.
4. High safety: low irritation and compatibility
PDMS is chemically inert and does not easily react with the skin or other ingredients. It rarely causes allergies or irritation and is suitable for sensitive skin. In addition, it has good compatibility with other active ingredients (such as vitamins and antioxidants), which can help stabilize the formula and extend the shelf life of the product.
5. Other functions
Sunscreen auxiliary: Improve the water resistance and uniformity of sunscreen products.
Oil control and astringency: Reduce oiliness by absorbing oil, but the effect is weaker than physical oil-absorbing ingredients (such as clay).
Makeup removal auxiliary: Help dissolve makeup in makeup removal products, especially effective for waterproof substances.
Controversy and precautions
Although PDMS is relatively safe, some people may be concerned about the following issues:
Breathability: Long-term use of high-concentration products may not be friendly to oily and acne-prone skin, and there is a risk of pore clogging (need to be judged in combination with the overall formula).
Environmental controversy: It is a difficult-to-degrade substance and may cause a cumulative burden on the ecological environment.
Summary
Dimethicone plays the role of "physical protector" and "texture regulator" in skin care. By balancing moisturizing, breathability and skin feel, it has become an indispensable ingredient in modern formulas. When choosing, you need to judge according to your personal skin type and needs (such as moisturizing, pre-makeup, repair), and pay attention to thorough cleaning to avoid residue.
