PEG-400

PEG-400 is a polyethylene glycol, a synthetic polymer derived from petroleum. It functions as a humectant, solvent and emulsion stabiliser in skincare formulations. In practical terms, it helps dissolve ingredients that wouldn't normally mix well together and improves the overall stability and feel of a product.PEG-400 appears in a small percentage of skincare products, typically at concentrations below 10%. Its primary role is structural rather than therapeutic—it enables formulators to create stable, homogeneous products and can help other actives penetrate the skin more effectively.

PEG-400 is a hygroscopic substance, meaning it attracts and binds water molecules. When applied to skin, it draws moisture from deeper layers into the stratum corneum, supporting hydration. Additionally, its molecular structure allows it to dissolve ingredients that are otherwise insoluble in water or oils alone, enabling more effective formulation design.Research suggests PEG-400 may also influence how the skin's outer layer behaves, potentially affecting the penetration pathway of other active ingredients. This makes it particularly useful in formulations designed to deliver specific acti…

PEG-400 is typically a background ingredient rather than something you need to use strategically. Since it appears in small concentrations within formulations, simply use the product as directed. If you're using multiple products containing PEG-400, there's no concern about layering or interaction—the ingredient is present in too low a concentration to cause issues when combined with other formulations.

PEG-400 is generally recognised as safe for skincare use and is well-tolerated across skin types. Some individuals with very sensitive skin may experience mild irritation, though this is uncommon.