Science
Mechanism of Action
Silicones establish a flexible, water-resistant film on the skin, effectively acting as occlusives to minimize transepidermal water loss (TEWL) and retain moisture, thereby boosting overall skin hydration. They impart a visible smoothing effect by physically filling in imperfections and fine lines, leading to an 'airbrushed' finish. Beyond surface benefits, silicones can stimulate fibroblast activity and collagen production, which may enhance skin elasticity and strength. In wound care, they reduce scarring through occlusion, hydration, and by modulating specific growth factor expressions, while allowing skin perspiration to escape.
Research
Clinical Evidence
High confidenceFor skin conditioning and barrier benefits in leave-on products, concentrations of 2-5% are recommended. Dimethicone, a common silicone, is recognized by the FDA as safe and effective as a skin protectant in the 1-30% range.
Key findings
- 01 Concentrations of 2-5% are recommended for leave-on products, such as moisturizers and serums, to provide skin conditioning and barrier benefits.
- 02 Dimethicone is recognized by the FDA as a safe and effective skin protectant when used in concentrations ranging from 1% to 30%.
- 03 In primers and makeup, concentrations exceeding 50% are effective for smoothing skin texture and concealing pores.
- 04 Silicone-based products, including patches or gels at up to 100% concentration, have been shown to improve the thickness, color, and elasticity of hypertrophic and keloid scars over 1-16 months.
Transparency
Dusting Analysis
Silicon refers to a broad family of synthetic polymer compounds (silicones), which are formulated ingredients rather than a raw material that would typically be 'dusted'. Their efficacy is concentration-dependent based on the specific silicone type and application.
The Formula
Formulation
Stability
Silicones are notably stable compounds, exhibiting resistance to a wide temperature range (-100 to 250°C), moisture, UV radiation, acids, alkalis, and ozone. While primarily hydrophobic, specific derivatives such as Dimethicone Copolyols are made water-soluble through the incorporation of polar groups.
Conflicts
- Can form a barrier on the skin that may impede the optimal penetration of beneficial ingredients from subsequent product layers.
- The occlusive film created by silicones may trap dead skin cells, oil, and bacteria if not properly cleansed, potentially exacerbating acne for susceptible individuals.
- Water-insoluble silicones can reduce the lathering capacity of shampoos and other cleansing products.
- Pilling can occur when certain natural oils and water-based serums are applied over a silicone-containing product, potentially hindering their absorption.
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel has deemed frequently used silicones, such as dimethicone, safe for use in cosmetic products, concluding their large molecular weights render skin absorption unlikely. Dimethicone is classified by the FDA as Category 1 (recognized as safe and effective) for skin protectant use up to 30%. However, regulatory bodies like the European Cosmetic Regulation (EC) No. 1223/2009 have banned Cyclotetrasiloxane (D4) due to endocrine disruptor concerns, and restricted Cyclopentasiloxane (D5) and Cyclohexasiloxane (D6) to a maximum of 0.1% in rinse-off cosmetics due to their classification as 'Persistent, Bioaccumulative, and Toxic' (PBT) substances. The maximum reported concentration for Dimethicone in products resulting in dermal contact is 85%.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Silicones are valuable for their ability to form a breathable skin barrier, provide significant hydration, improve skin texture, and offer targeted benefits for scar management, although specific cyclic forms face environmental and regulatory restrictions.
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