Silicone

Silicone Quaternium-25

INCI: SILICONE QUATERNIUM-25

Reviewed by Emma · Last updated 14 Aug 2026

Also known as: Silicone Quaternium-25

A silicone conditioning agent that smooths skin texture and provides a lightweight feel

Best For Skin Types

All, Oily, Dry, Combination, Sensitive

Addresses

Dryness, Hydration, Barrier repair

Usage Frequency

Daily

What Is Silicone Quaternium-25?

Silicone Quaternium-25 is a silicone-derived conditioning polymer used in skincare formulations. It belongs to a family of silicones that have been refined for cosmetic and pharmaceutical use since the 1940s, where they are now found in approximately 60% of modern skin-care products.

This ingredient functions as an emollient and skin conditioner, depositing a thin protective layer on the skin's surface. It is valued for creating a smooth, non-greasy finish without visible residue or staining.

How It Works

Silicone Quaternium-25 works by adhering to the outer layer of the skin, creating a smooth, lightweight film. This film helps to lock in moisture and prevent transepidermal water loss whilst remaining invisible to the eye.

The quaternised structure of this silicone gives it conditioning properties that help improve skin feel and the sensory experience of a product, making formulations feel silky rather than occlusive or heavy.

Clinical Evidence & References

Silicones as a class are considered safe excipients in topical formulations and pharmaceutical applications, with extensive use in medical devices and skincare since the mid-20th century. The evidence base supports their tolerability and their ability to provide a pleasant sensory profile without adverse effects in typical cosmetic concentrations.

However, specific clinical data on Silicone Quaternium-25 in isolation is limited in published literature. General silicone safety assessments indicate these agents are well-tolerated by most skin types when formulated appropriately.

How to Use

Silicone Quaternium-25 is typically incorporated into serums, moisturisers, primers, and conditioning treatments. It works well layered under or over other skincare products and is compatible with most active ingredients. If you are using multiple silicone-containing products, monitor how your skin responds, as layering may alter the overall texture or finish.

Safety & Precautions

Silicone Quaternium-25 is generally well-tolerated and is used widely in cosmetic formulations. Those with extreme silicone sensitivity should patch test, though adverse reactions are rare at typical usage concentrations.

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