Why add cyclosilicone oil in the product? Volatile methyl cyclosiloxane, commonly known as "cyclosilicone oil", is not a single component, but a generalization of a class of substances.


This is a kind of artificial compound with special physical and chemical properties, which does not exist in nature.


In the 1940s, it was first synthesized by Dow Corning in the United States and began to be applied in the industrial field.


There are many members of the cyclosilicone oil family, the most common ones are:


Octamethyltetracyclosiloxane (D4), decamethylcyclopentasiloxane (D5)


D4 and D5 are common base oils in skin care products.


It has the advantages of clear texture, tasteless, non-irritating, and low cost. It is also compatible with a variety of cosmetic ingredients and has good spreadability. Therefore, cyclosilicone oil is often used as a carrier in cosmetics to help other substances evenly adhere to the epidermis, making the product easy to apply.


Adding cyclosilicone oil in cosmetics can also bring a comfortable skin feel. Cyclosilicone oil has the characteristics of being volatile and is often used to create "absorption". After application, it has a soft and silky feel, and the skin feels refreshing and not sticky. If you see that silicone oil is placed very high in the ingredient list, most of them are designed to create a sense of absorption.


Based on these superior characteristics, cyclosilicone oil is often used as an emollient, moisturizer, solvent, antistatic agent, viscosity control and hair conditioning agent, and the amount of addition ranges from 1% to 50%.


It has been widely used in many fields including skin care products.


How widespread is it?


Look at the two sets of numbers:


One is the addition ratio.


Research reports show that the common addition in industrial products is between 0.5-10%, but for many baby products, skin care products, antiperspirants and other special products, the addition may exceed 10%, or even more than 30% .


The second is the output value of the raw material production industry.


In 2009 alone, China surpassed the United States to become the world's largest producer and user of methyl cyclosiloxane, with a total output and usage of 270,000 and 430,000 tons.


By 2013 and 2014, the total annual domestic production capacity was 1 million tons and 1.135 million tons respectively. According to statistics, the overcapacity rate did not exceed 10%.


It should be noted that not only in China, cyclosilicone oil is a basic ingredient that is widely used worldwide.


Special emphasis:


Whether it is D4 or D5, in any country, it is still a component that can be used legally.


The legislation introduced by the European Union only restricts the content, not prohibiting use.


So, what is the reason for such a huge industry and so many years of extensive application? The EU has to issue regulations to restrict it?


2


Identified risk


Due to the volatility of cyclic silicone oil, with the mass production and application of cyclic silicone oil, it has been continuously accumulated in environmental media. In recent years, it has been listed as an organic pollutant in many countries.


Countries and regions such as Northern Europe, Canada, and the European Union have also successively carried out risk assessments of silicone oils.


This includes not only the monitoring of the atmosphere, sediment, soil, and water quality, but also the study of biological toxicity.


These studies are different, but the following conclusions are relatively clear, which is an important basis for this EU legislative restriction.


1. High concentration of D4, with reproductive toxicity


Relevant studies have shown that D4 may have direct or indirect effects on reproductive capacity and has reproductive toxicity.


D4 can interfere with estrogen receptors in organisms and greatly reduce the number of ovulation in females.


In the experiment of respiratory exposure to rats, in the high-dose group, D4 can interfere with the reproductive system of female mice and reduce the chance of conception. The birth rate of mice is reduced, and the weight of newborn mice is also reduced.


In addition, D4 can cause fatal damage to the liver and lungs.


Although there is no direct report on the effects of D4 on the human body, as biological experiments have verified its reproductive toxicity, the general consensus is: for safety reasons, pregnant women, pregnant women and breastfeeding women should strictly avoid using products containing D4 ingredients .


2. D4 and D5 are both bioaccumulative and environmentally persistent, and will especially cause adverse effects on water organisms


Due to the high volatility of cyclosilicone oil, nearly 90% of the cyclosilicone oil in the environment of cosmetics and personal care products will volatilize into the atmosphere, and the remaining 10% will enter the environmental water body with the discharge of domestic wastewater, resulting in its continuous composition It accumulates in the environment and enters organisms and even human tissues through the atmosphere and water.


Cyclosilicone oil has a half-life of more than 2 days in the atmosphere, and can travel long distances through atmospheric circulation, even reaching the polar regions.


After cyclic silicone oil enters the soil, the half-life exceeds 182 days, and if it enters the water body, the half-life in the bottom mud can even exceed one year.


Recently, scientists detected D5 in the air and fish in remote areas of Sweden. In addition, D5 was found in water bodies, sea mud, and biological samples in the Arctic region.


For seawater and freshwater organisms, the impact of D4 and D5 on aquatic organisms is related to the concentration in the water body.


Beyond the safe concentration range, it will cause harm to aquatic organisms. D5 especially has a significant accumulation effect in the bodies of invertebrates and fishes and other aquatic animals, which can cause neurological disorders and other adverse effects, and there is also the possibility of carcinogenesis.


Based on such research, the purpose of this formal legislation of the European Union is to limit the added content of D4 and D5 in washing products, precisely to avoid further damage to the survival of water organisms.


However, skin care products such as creams that are applied to the surface of the skin have less impact on the environment than water-washed products. The addition ratio is also within the safety range of the human body. Currently, there is no further restriction. Please don't worry too much. .


However, in addition to these relatively certain risks, there are some potential risks that need attention.


3


Potential risks


According to some opinions of the European Union and other countries, the current dosage of D5 is relatively safe.


For example, the CIR expert group in the United States believes that D5 is safe under the current usage and dosage conditions; the Canadian government also believes that D4 is a risky substance that may cause environmental and reproductive toxicity, while D5 is not at the current ratio. Danger to human health.


However, from the risk assessment reports of various countries, we still found two types of potential risks.


1. D4 concentration contained in D5 raw materials


In October 2016, the European Union Scientific Committee on Consumer Safety issued an evaluation opinion on the D5 ingredient:


Due to the particularity of the production of cyclic silicone oil, a certain proportion of D4 may be contained in D5, because it is currently clear that D4 is classified as a substance with reproductive toxicity in the European Union. Therefore, the European Union requires its related products, and the purity of D5 needs to reach more than 99% of the European Union's requirements, so as to prevent the D4 contained in it from exceeding the safe concentration.


2. High concentration of D5 may cause cancer risk


In a two-year chronic toxicity study, Dow Corning found that D5 is carcinogenic, and the incidence of uterine cancer in mice in a high-concentration environment has increased significantly.


The Danish Environmental Agency also evaluated the toxicity of D5, and the results showed that high concentrations of D5 were found to be carcinogenic in a two-year repeated respiratory exposure experiment in mice, and the incidence of uterine tumors was higher than that of lung and liver. Impact.


Although D5 is currently proven to be an ingredient that can be used in a safe proportion, it also has the above-mentioned risks.


In this way, if you don't need it, don't use it as much as possible.


At the very least, our own products, when scientists develop formulas, completely avoid using any cyclic silicone oil raw materials.


First of all, it is difficult to determine the safe ratio range of the human body


Although there is a saying that "aside from dose and toxicity, it is a hooliganism", but the problem is that D5 has been proven to be bioaccumulative.


With the accumulation of existing safe doses over time, it is difficult to say when they have accumulated to exceed the safe range of the human body.


What's more, the raw material itself has the problem of the purity of D4 contained in it, which is also a risk.






Secondly, scientific exploration is a process of continuous development.


Existing research believes that the current addition ratio is safe. It is just based on existing scientific research methods and does not represent the fact that this is the case. It is not ruled out that in future studies, it may be found that the currently considered safe dose is actually not safe enough, and there is still a risk of adverse health.


Summary


Components such as cyclosilicone oil were originally used as substitutes for mineral oil components in daily chemical products. Now that many shortcomings such as difficulty in degradation, environmental pollution, and harm to organisms have been discovered, it is believed that with the development of society, such risk components will also Was slowly eliminated.


In this way, the EU’s formal legislative restrictions may be just the beginning.


In fact, the risk controversy over D4 and D5 has been around for a long time. Therefore, more and more daily chemical manufacturers are developing safer and better-performing alternative products. Perhaps in the near future, with the development of scientific research, there will be better alternative ingredients.


Prior to this, for D4, D5 and other cyclic silicone oil components, whether from an environmental protection point of view or from a safety point of view, warnings and attention should be given, and the use of them should be minimized or avoided.