The widely used dimethylsilicone oil in cosmetics may have trace amounts of residual solvents or incompletely polymerized silicone monomers during actual production, which has drawn attention from some consumers. However, as long as one chooses regular brand products that meet the national filing requirements, their safety is guaranteed and there is no need to worry excessively. We can comprehensively understand this issue from the following three aspects. 
I. Sources of Residual Substances and Process Control
The residual substances that may exist in cosmetics mainly originate from the production process: Firstly, there are unreacted cyclic siloxane monomers such as D3, D4, D5, etc. Due to the difficulty of achieving 100% polymerization efficiency in chemical reactions, these volatile organic impurities may be present in trace amounts and thus are classified as substances that need to be strictly controlled. Secondly, in some low-viscosity products, ethyl alcohol and other process solvents may be used. However, the mainstream cosmetic-grade dimethylsiloxane oil currently adopts solvent-free polymerization processes, and the risk of residual solvents has been extremely low. 
II. Strict Regulations and Standard Control
To ensure consumer safety, regulatory agencies both at home and abroad have set clear limits for the residues. For instance, the European Union prohibits the use of D3 in cosmetics and sets a strict limit of no more than 0.1% for D4 and D5 in persistent products. China's "Cosmetics Safety Technical Specifications" also requires that raw materials and final products must meet safety standards. Regular manufacturing enterprises not only strictly control residues such as D4 and D5 in accordance with international standards (usually ≤ 0.1%), but also test the volatile monomers in raw materials and conduct a comprehensive assessment of the safety of final products. 
III. Safety in Actual Use
At the practical usage level, the health risks brought about by compliantly produced cosmetics can be disregarded. The content of volatile substances remaining in the products is far below the safety threshold, and they tend to evaporate and disperse after application, not accumulating on the skin surface. Dimethylsiloxane, as a raw material for cosmetics, has been safely used for several decades. Currently, there is no evidence suggesting that compliant products that meet regulatory requirements will cause allergies, irritation, or long-term health problems. 
In conclusion, the issue of residual dimethylsilicone oil in cosmetics has been effectively controlled under strict production processes and regulatory standards. Consumers can use the products safely by purchasing them from official channels that meet the registration requirements of the brand.