Silicone oil in shampoo

The hair is smooth and smooth after washing. It is because the chemical components such as silicon or dimethylmethyl are added to the shampoo. The inherent water impermeability and other inertness of the silicon will also close the pores and cause the scalp. It is easy to itch, and may even have hair loss and sequelae of hair loss.

Saying that shampoo contains "silicon" does not mean that it contains silicon, but dimethicone. (Dimethyl) silicone oil is a common name for polydimethylsiloxane (PDMS) which is liquid at normal temperature, and is also called "矽灵". By increasing the degree of polymerization, there will be solid PDMS. Regardless of the state, all PDMS are always a class of substances with the same structure.
This structure determines that PDMS is a class of "inert" substances that are inherently chemically stable. Since the 1950s, after testing the water from silicone oil to personal care products, it has not been able to get in and out. Since the 1970s, PDMS has been stationed in shampoos and hair care products, taking away Thousands of years of application of historical vegetable oil, cetyl alcohol and other ingredients.

Why do we need silicone oil?
Hair is produced by hair follicles in the scalp, mainly keratin. Enlarge the hair, the uneven hairs (hair scales) are clearly visible, like fish scales. Shampooing is to remove dust and excess oil from the hair and scalp, but water and decontaminating surfactants can cause a series of changes in the hair: hair swells, wet and soft, usually attached to the hair The oil that protects the skin from external lubrication is washed away. If there is damage to the raised scales, it will increase the friction between the hairs, causing the hair to entangle when combing, and the mutual friction will increase the damage of the scales. This is not complete. It is obvious that the negatively charged hair that the surfactant is wet can also be put together under the action of water. When it is dry, it can completely turn its face, because the same-sex repelling is far from each other. If you use a plastic comb to comb the static electricity, it will be lively~~~

The problem of static electricity caused by anionic surfactants is well solved. We have a cation in the conditioner, a series of quaternary ammonium salts. This can not solve the problem of a series of hair types that start with hair scale damage. This is not avoided without combing the hair - in addition to combing, chemical agents when dyeing, heat and ultraviolet light in the sun, it is a great injury to the hair. At this time, the oil comes in handy: lubrication to reduce the osmanthus oil from the dressing table of the ancient girls to the conditioner on the shelves decades ago, the protagonist is grease. The role of PDMS is to attach to the hair, cover the damaged parts of the scales, and make the surface of the hair smoother, which is the "repair" function often mentioned in advertising. After the "repair" of the hair, the light is easy to comb, not to mention, and it is stronger.

PDMS also has an advantage: the protective layer formed can obviously keep the moisture content inside the hair stable - and the hair classification after using shampoo alone, the hair using the conditioner has reduced water loss under low humidity conditions, and under high humidity conditions Prevent excessive moisture absorption. If the hair is too wet or too dry, it will cause difficulty in combing and hair style changes.

Does silicone oil in toiletries affect the health of the scalp?
The hair care effect of PDMS is obvious to all, especially for incisions or hot dyed hair - such hair, hair scales are more serious damage. However, because it works by leaning against the hair and exposing the damaged scales, some people are beginning to worry about whether it will also deposit on the scalp, causing redness, inflammation, acne, hair loss and the like.

First, the Cosmetic Ingredient Evaluation (CIR) panel believes that it is safe for cosmetics [2] and is not irritating to the skin. Although it forms a hydrophobic membrane on the skin, it is also breathable. In the process of searching for documents, I did not find any information related to acne, acne, hair loss, and allergies. It is often used in products marked with no acne (no acne) or no oil (no oil). in. This is also its advantage over traditional oils.

Most shampoos add a small amount of PDMS and hope to achieve some hair care while cleaning the hair. But in fact, like this product has a very limited hair care effect (the hair is still very frizzy with wood!), it is also low on the scalp to clog pores. Because the amount of PDMS added to the shampoo is very small (less than 1%), the washing with a large amount of water is almost exhausted by the action of the cleaning surfactant. Hair conditioners, hair masks, and rinse-off conditioning products containing a large amount of silicone oil have not been recommended for use on the scalp, as long as they are applied to the ends of the hair and above. One is to reduce the amount, and the other is that the hair scales in the hair roots are less damaged, and it is not necessary to use these products. The third is to reduce the greasy feeling and heavy collapse of the hair roots.

In addition, improvements in the structure of the PDMS - which can be etherified or added to the amino group, can greatly enhance the ability of silicone oil to bond with the hair while improving. Such products can be more effectively attached to the hair, and in the skin and other friends who have been weighed by "silicone oil clogged pores", it is not necessary to be too excessive.

It should be noted that adding PDMS to shampoo products sometimes has small drawbacks. For example, people with short hair rarely have the need for hair care. If they choose a product that contains PDMS, they have to bear the extra cost. For some soft hair, "," will be absorbed by the PDMS on the hair, causing hair. It becomes thicker, the weight becomes larger, and at the same time, the static electricity between the hairs is reduced. Then, after the hair is dry, it usually piles up and collapses, and is not fluffy. This is not a good phenomenon [4]. In this case, we still have a choice of shampoos that exclude PDMS.

Conclusion: PDMS can smooth the scales and reduce the frictional damage of the hair, and the immediate or long-term benefits are the consequences. On the contrary, its harm to the scalp is not confirmed. Why, say "no" to it? Of course, if you are short-haired, do not need so much protection, or do not like silicone oil, you can choose shampoos that do not contain PDMS, conditioners - they contain cetyl alcohol, stearyl alcohol or Some of the ingredients such as sunflower oil, and some of them are indeed acne-prone and acne-producing.