Dimethiconol/Silsesquioxane Copolymer

Dimethiconol/Silsesquioxane Copolymer is a hybrid silicone ingredient combining two chemical structures: dimethiconol (a conditioning silicone oil) and silsesquioxane (a cage-like silicone polymer). This combination creates a lightweight conditioning agent that sits on the skin's surface rather than penetrating deeply.In skincare, it functions as both a skin conditioning and protective agent, helping to create a smoother feel and reduce transepidermal water loss. It's commonly used in moisturisers, primers, and protective serums.

This copolymer deposits a thin, breathable film on the skin surface. Because of its molecular structure, it creates a barrier that slows transepidermal water loss whilst remaining light and non-comedogenic. The ingredient is water-repellent, so it works well in water-in-oil or hybrid formulations.Unlike heavier occlusive agents, dimethiconol/silsesquioxane copolymer doesn't feel heavy or build up on skin, making it suitable for products aimed at multiple skin types.

This ingredient works best when applied to clean, slightly damp skin as part of a moisturiser or serum, allowing it to lock in hydration. In layered routines, apply it after lighter hydrating steps but before heavier creams if using multiple products. It pairs well with humectants like glycerin and hyaluronic acid, which draw water into the skin whilst this ingredient helps retain it.

Generally well-tolerated and considered safe for cosmetic use. Non-comedogenic silicone polymers are unlikely to clog pores, though those with silicone sensitivity should patch test first.