Dimethicone

skincare activeLow concern

Also on labels as: polydimethylsiloxane, PDMS, dimethyl polysiloxane, E900

In one line

A synthetic silicone polymer that forms a smooth, protective film on skin and hair.

What is Dimethicone?

Dimethicone is a man-made silicone oil built from repeating silicon-oxygen units with methyl groups attached. It is synthesised from silicon, a mineral derived from quartz, rather than harvested from a plant or animal. The result is a clear, odourless fluid whose consistency ranges from thin and watery to thick and gel-like depending on chain length.

What does it do in the product?

In leave-on cosmetics, dimethicone spreads across the surface of skin or hair to create a lightweight, water-resistant barrier that locks in moisture and reduces friction. In makeup, it gives products a silky slip and helps them glide on evenly without a greasy feel. In oral over-the-counter medications, a closely related form called simethicone uses the same chemistry to break up gas bubbles in the digestive tract.

Where you usually find it

moisturising lotions and creams
hair conditioners and serums
foundation and BB creams
anti-chafe balms and barrier creams
anti-gas oral tablets (simethicone products)
sunscreen formulas

Is Dimethicone something to worry about?

Regulatory bodies in both the US and EU have reviewed dimethicone and found no evidence of toxicity at concentrations used in consumer products, and it is not classified as a skin sensitiser. Because it sits on the surface rather than penetrating deeply, systemic exposure from topical use is considered negligible. Some people with acne-prone skin report that heavy silicone-based formulas feel occlusive and may contribute to congestion, so personal skin tolerance is worth considering even though the ingredient itself is not classified as comedogenic by regulators.

Who should pay attention

Acne-prone skin: heavier dimethicone formulas may feel occlusive; light-textured versions are less likely to cause issues
Silicone sensitivity: rare, but those who react to silicone-based medical devices should patch-test
Vegans and plant-based consumers: dimethicone is synthetic and not animal-derived, so it is generally accepted as vegan
Environmentally conscious shoppers: silicone polymers are slow to biodegrade and accumulate in aquatic sediment, which is an ongoing research concern
Readers with nut or latex allergies: dimethicone itself poses no allergy risk from those sources, but always check the full label

How is it regulated?

In the United States, the FDA permits dimethicone as a skin protectant active ingredient in over-the-counter drug products at defined concentrations and also approves it as a food-grade antifoaming agent under its food additive regulations. The European Union lists it as E900 (polydimethylsiloxane) for limited food applications and permits its use in cosmetics without restriction at current industry-standard concentrations, based on safety assessments by the Scientific Committee on Consumer Safety.

How to spot it on a label

On ingredient lists, look for 'dimethicone' or the longer chemical name 'polydimethylsiloxane'; a number in parentheses such as dimethicone (6 cst) refers to its viscosity grade rather than a separate substance. When you see it listed near cyclomethicone, cyclopentasiloxane, or phenyl trimethicone, the formula is heavily silicone-based. InZoRAH will flag the full silicone cluster so you can see exactly how much of the formula it represents.

What a cleaner swap looks like

If you prefer to avoid synthetic silicones, look for products that use plant-derived alternatives such as squalane (from sugarcane or olive), oat beta-glucan, or a blend of natural waxes and plant oils to deliver similar smoothing and barrier effects. These swaps tend to biodegrade more readily. Keep in mind that the texture and spreadability will differ, and natural oils are not automatically lower-risk for acne-prone skin.

Questions people also ask about Dimethicone

Is dimethicone safe to use on skin every day?

The available safety record supports daily topical use for most people. Regulatory reviews in both the US and EU found no evidence of toxicity or sensitisation at concentrations used in cosmetics. People with breakout-prone skin may want to try lighter-weight formulas, but the ingredient itself is not classified as harmful by major regulators.

Does dimethicone absorb into the bloodstream through the skin?

Dimethicone molecules are large enough that they do not readily penetrate the skin barrier. Studies reviewed by safety committees found that systemic absorption from normal topical use is negligible. This is one reason regulators consider it low-risk compared with smaller molecules that can cross the skin more easily.

Will dimethicone clog pores or cause acne?

Dimethicone is not formally classified as comedogenic by cosmetic science standards, and controlled studies have not confirmed that it causes acne. However, thicker silicone-heavy formulas can feel occlusive on some skin types, and anecdotal reports of congestion are common. Those prone to breakouts may do better with water-based or non-silicone alternatives and should patch-test new products.

Is dimethicone the same as simethicone in gas-relief tablets?

They share the same silicone chemistry. Simethicone is essentially a mixture of dimethicone and silicon dioxide used in oral medications to disperse gas bubbles in the gut. The name and grade differ from the cosmetic form, but both descend from the same polydimethylsiloxane backbone. The oral grade is separately regulated as a drug active ingredient.

Is dimethicone bad for the environment?

This is an area of active research and genuine uncertainty. Silicone polymers break down slowly in the environment, and some studies have detected them accumulating in aquatic sediment and in organisms that live there. Regulators have not banned cosmetic dimethicone, but environmental agencies in several countries are monitoring silicone accumulation and reviewing limits for certain related compounds.

Is dimethicone vegan and cruelty-free?

Dimethicone is synthesised from silicon-based raw materials and contains no animal-derived ingredients, so it is generally considered vegan. Whether a finished product is cruelty-free depends on the brand's overall testing policies, not on dimethicone specifically. Checking a brand's cruelty-free certification is the most reliable way to confirm.

Where this came from

FDA over-the-counter drug monograph for skin protectants — Establishes dimethicone as a permitted active ingredient at defined concentrations for topical OTC drug use in the US
FDA food additive regulations (antifoaming agents) — Permits polydimethylsiloxane as a food-grade antifoaming agent in specified food and beverage applications
EU Scientific Committee on Consumer Safety (SCCS) safety opinion on silicones in cosmetics — Supports the conclusion that dimethicone at current use concentrations does not pose a safety risk to consumers in cosmetic products
European food additive register (E900 listing) — Documents the approved food uses and conditions for polydimethylsiloxane within the EU regulatory framework

Original write-up based on public records. Educational information, not medical advice — ingredient records change, so always read the physical label if you have an allergy.

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