Is silicone really safe?


Silicon, which is often called organosilicon in Chinese, is translated by Taiwan compatriots into Siling or Silikon. The commonly used name of silicone oil is also a general name for a part of silicone products. Specifically, the silicone products include PDMS, such as D4, d5 and D6, and emulsified silicone oil (commonly used in shampoo). These three products are often called silicone oil. In addition, there are silicone wax, silicone elastomer and other silicone products. Although it is not very scientific, but for convenience and the reason of word density (not explained), these organosilicon products are collectively referred to as silicone oil in the following article.






Silicone oil was first developed for military use in World War II. Silicone oil has been used in the cosmetics industry for decades. Silicone oil was first used in shampoo and deodorant in the 1970s. After decades of development, it is widely used in cosmetics or personal care products, especially in skin care products and cosmetics. Such a wide range of silicone products (silicone oil is used instead of the following), is it really safe for human body?






Special properties of organosilicon


Generally, physical and chemical properties can be deduced from the structure. But here, we don't need to analyze the chemical structure formula of silicone oil specifically, and the general consumers don't need to know these. Therefore, it is only a simple concept of the properties of silicone oil: very stable structure, not easy to degrade, and not easy to react with other substances under general conditions. At the same time, chemical bonds are flexible, easy to move, and low surface tension, so smooth is the most common property. In addition, it is waterproof but breathable. It is an indispensable material in all walks of life.






Safety of silicone oil to human body


At present, it is believed that PDMS is not absorbed by human skin and gastrointestinal tract, has almost no acute toxicity, has no irritating effect on skin, has irritating effect on eyes, and can cause mild conjunctivitis or erythema. There is no evidence of teratogenicity, carcinogenicity and genotoxicity of PDMS. It is reasonable to think that PDMS will not cause health hazards under the existing normal use.






And the claim that silicone oil causes hair loss is not rigorous either. It is true that hair loss is caused by shampoo, but it may be caused by preservatives, flavors, or other surfactants. Silicone oil is only possible. If one day you use brand a product to lose your hair, and change to brand B shampoo which also contains silicone oil, do you think it's because of silicone oil? On the contrary, my personal experience is that it's OK to use some shampoo containing silicone oil, but after using a domestic silicone free shampoo, the hair will brush off.






Therefore, there is no scientific basis for the frequently reported hair loss caused by silicone oil. If hair loss is caused by using the shampoo containing silicone oil, you should consider whether the whole product is the problem and not let silicone oil be the scapegoat.






Although the above are all about the safety of silicone oil, it does not mean that silicone oil is a safe 100% cosmetic ingredient without safety concerns.






Impurities affect the safety of silicone oil


As with many raw materials, in various series of silicone oil products, many are not 100% pure substances, and there are some impurities in them. One of the notable impurities is D4 (to add, D4 is the abbreviation of cyclotetradimethylsiloxane, D5, D6 and so on). D4 is a monomer for the synthesis of these silicone oils, and various organosilicon compounds are formed through ring opening polymerization. But in the process of synthesizing all kinds of silicone oil, it is difficult to completely react D4. Therefore, D4 will remain in some silicone oil products.