Silicones in skincare: what they do on your skin and why silicone-free isn’t proof of quality

NATURAL SKINCARE

What do silicones do in skincare?

In skincare, silicones mainly do one thing: they change how a product spreads and feels on the skin. Chemically, they are chains of silicon and oxygen with methyl groups, and they are entirely synthetic. Depending on chain length and shape, the results are very different. Short, ring-shaped silicones such as cyclopentasiloxane evaporate after application and act as a light carrier that lets a cream ‘sink in’ quickly. Linear silicones such as dimethicone stay on the skin as a thin, smooth film and create the velvety feel that many people associate with a high-quality texture. Cross-linked silicones, known as crosspolymers, give primers and creams a powdery, matte finish. The Cosmetic Ingredient Review expert panel assessed 62 of these dimethicone crosspolymers and describes their roles as including film formers, emollient skin-conditioning agents, slip modifiers and thickeners for water-free products.

What silicones are not is an active skincare ingredient in the strict sense. They provide neither moisture, as hyaluronic acid does, nor lipids, as ceramides do. Their contribution is texture, shine in hair and a degree of protection against water loss thanks to the film. You will also notice that a cream with silicones behaves differently from one without when you layer several products. If your skincare starts pilling into little rolls, the interplay of film formers is often behind it – more on this in why your cream balls up on your face.

Are silicones bad for your skin?

No – according to the available data, the silicones commonly used in skincare are not harmful to the skin. The most thorough assessment comes from the Cosmetic Ingredient Review, a US expert panel that systematically evaluates cosmetic ingredients. Its final report on dimethicone and related silicones, published in the International Journal of Toxicology, states that dimethicone was not absorbed after application to the skin in clinical and animal studies. In most irritation tests it was classed as a minimal irritant, and in a repeated patch test with 83 people it did not cause sensitisation at a concentration of 5.0 per cent. Because of the large molecular weight, the panel considered it unlikely that these polymers penetrate the skin to any significant extent, and it rated them as safe at the usual use concentrations of up to 15 per cent.

That does not mean every silicone cream suits every skin. If your skin does react to a product, however, fragrances, essential oils or individual preservatives are far more often the cause than the silicone. Which of these substances genuinely matter for sensitive skin is covered in the article on skincare without additives. If you avoid silicones anyway because you do not like how they feel on your skin, that is a perfectly legitimate reason. It just is not a health reason.

Do silicones clog pores?

There is no evidence that silicones clog pores, and dimethicone itself is not considered a typical trigger of blackheads. The myth comes from the way it feels: a silicone film feels smooth and sealed, so it is tempting to imagine that the skin underneath can no longer ‘breathe’. But a thin film on the surface is not the same as a plug in the follicle. Whether a product encourages breakouts for you depends more on the formula as a whole – on heavy oils and waxes, on the amount you apply and on how thoroughly you cleanse in the evening. With primers and make-up that contain a lot of silicone in particular, it pays to use a cleanser that genuinely dissolves the film. Why a list of individual raw materials tells you less than the finished formulation is explained in detail in the article on comedogenic ingredients. The honest test remains the same: use a new product for a few weeks as the only change and watch what happens, rather than judging by an ingredient list.

How do you spot silicones on an ingredient list?

You can spot silicones on the INCI list by typical name components, above all ‘-cone’ as in dimethicone, ‘-siloxane’, and ‘silicone’ or ‘siloxy’. Ingredients are generally listed in descending order of quantity, so the further up a silicone appears, the more of it the product contains. These are the names you will come across most often:

A common mix-up: silica is not a silicone. It is silicon dioxide, a mineral powder used in creams and powders to reduce shine, for example, or to help powders flow freely. The only thing it shares with silicones is the element silicon. The same goes for clay minerals such as Magnesium Aluminum Silicate. So if you simply scan the list for ‘sili’, you can easily end up with a false alarm.

How valid is the environmental criticism of silicones?

The environmental criticism has substance, but it mainly concerns three cyclic silicones rather than silicones across the board. In 2018, a committee of the European Chemicals Agency identified D4, D5 and D6 as substances of very high concern because they are very persistent and accumulate very strongly in living organisms; D4 is also considered persistent, bioaccumulative and toxic. According to EU Regulation 2024/1328, widespread use in cosmetics is the main route by which these substances reach the environment. The result is a restriction in two stages:

• D4 and D5 in wash-off products such as shampoo or shower gel: only permitted below 0.1 per cent since 31 January 2020.
• All other cosmetic products, including creams, serums and make-up, as well as D6 in any kind of cosmetic: likewise below 0.1 per cent after 6 June 2027.
• Linear silicones such as dimethicone are not restricted themselves. If they contain residues of D4, D5 or D6, however, the same limit applies to the finished cosmetic product.

That is EU law. In Switzerland, chemical restrictions of this kind are governed by a separate ordinance, but many products on Swiss shelves are formulated for the European market anyway.

That leaves the question of microplastics. The EU microplastics restriction (Regulation 2023/2055) explicitly covers only polymers that are solid. Liquid silicones such as dimethicone therefore do not fall under the legal definition. Things may look different for solid, cross-linked silicone particles, such as powdery crosspolymers, depending on the shape and size of the particles. Some shopping guides nevertheless count liquid synthetic polymers as ‘liquid microplastics’ – that is a matter of definition, not a measured finding. Conversely, the fact that a substance is not a microplastic in the legal sense does not mean it disappears quickly from the environment. The criteria that really count ecologically when choosing a cream are covered in the article on sustainable face cream.

Is silicone-free skincare automatically better?

No, silicone-free skincare is not automatically better – it is simply formulated differently. ‘Silicone-free’ tells you what is missing, but not what has taken its place or whether the formula suits your skin. Something has to take over the silicones’ jobs: plant oils, squalane, esters, waxes or polysaccharides. That can work very well, but on some skin types it can also feel richer or turn shiny faster than a silicone cream. You will know the same pattern from parabens: ‘paraben-free’ only means preserved differently, not safer. And swapping silicones for paraffin gains you little – that is a topic of its own, covered in mineral oil in skincare.

Other questions matter more when you are deciding what to buy. Which active ingredients does it contain, and at what concentration? Does the product contain fragrance? Does the texture suit your skin and the time of year? The Duo also does without silicones, but for us that is not proof of quality, simply a property of the formula. How that feels on the skin is subjective. In her review on Judge.me, Iris S. writes: ‘The cream absorbs quickly. Together, the two give a very smooth feel on the skin.’ (review translated from German)

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