Silicone: why is it in my moisturiser?

Daniel Judd BSc, MBiol

Silicone is a common ingredient in skincare products. Daniel Judd explains why.

If you’ve ever taken a thorough look through the ingredients of certain skincare products, you might have wondered why you’re rubbing your face with the stuff used to seal bathroom fittings. Silicone is a truly versatile ingredient with applications ranging from colourful cake moulds to many of the face and hair products you know and love. What’s important to remember is that just because it’s got all sorts of industrial uses doesn’t mean it’s not a great skincare ingredient too.

So why does silicone get used in so many ways and what makes it a good skin care ingredient? Silicone does a lot of the same things that natural oils can do. In skin care, oils from plant and animal sources are useful for several reasons: they can grab dirt in soaps and cleansing oils, they can help dissolve oil based ingredients like vitamin E and they can coat and protect the skin to keep it moisturised. Skin dries out when water evaporates off its surface but water can’t cross an oil barrier so silicone can help keep skin that water in and the skin moisturised.

In hair products, slightly different types of silicone can have different beneficial effects. Amodimethicone is used as a conditioner and hair protector since it can coat the individual hairs after their natural oils have been washed off during washing. This layer can protect hair from heat damage caused by blow-drying, curling or straightening. Another silicone, phenyltrimethicone, gives hair a shinier appearance and is sometimes used in hair colouring products.


So it might work well but surely a natural oil is safer than a synthetic one? Actually, silicones used in cosmetics have been found time and time again to be safe in the amounts typically used and aren’t harmful to the environment either. Silicones are also relatively unreactive, so ingredients that might be incompatible with natural oils can still be combined with silicones. It’s also worth that some natural oils in products can come from controversial and unsustainable palm oil plantations so ‘natural’ isn’t necessarily better.

Silicone in cosmetics isn’t without its drawbacks. Despite its low toxicity, it’s still possible to have an adverse reaction such as redness due to sensitivity. A more common issue is that as an oily ingredient, silicone can make oily skin and acne worse. It may also make  oily hair worse and you might need to rethink your choice of products in that case.

There are claims that silicone blocks the skin and ‘suffocates it’ and that it’s only used in products because its cheap. It may well be cheap, but it’s a good way of suspending other ingredients in skincare products on the skin so that can sink in and do their job, and it’s large molecular structure means that the skin is able to ‘breathe’, so to speak.

Ultimately, silicone makes for a perfectly suitable ingredient in a wide range of hair and skin products. It’s got low toxicity, low reactivity and does plenty of the jobs a natural oil does so there’s no need to worry that your conditioner and your cookware share it as an ingredient.