Silicone Is No Longer A Dirty Word In Haircare

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Constantly on a quest to make my tresses thicker, healthier and generally more Rapunzel-esque, I road-test new shampoos and conditioners all the time. But very rarely am I blown away by the results. I don’t coo in the same way that I would with a silky new serum, or bemoan reaching the end of a bottle, as when my Lady Danger lipstick gets worn down to the nub.
In part, I blame my haircare disillusionment on the ever-growing cult of wellness, where the lure of "free-from" now has such a hold on consumers that brands are constantly stripping back formulations in order to keep up with the zeitgeist. Now, in some cases, this is great; sodium lauryl sulphate (SLS), a surfactant that gives shampoo its foamy effect and cuts through grease, causes scalp irritation (in my case, weird little itchy bumps), so its removal is a welcome treat. The elimination of silicone, however, is much more questionable because it’s such an ambiguous character.
“Around 30 years ago, when silicones were first introduced into the haircare market, they were criticised for giving a coated feel to the hair and adding build-up that wasn’t easily washed away” explains the Unilever Research & Development team. I ask Adam Reed, L’Oréal Professionnel Editorial Ambassador for more details. He clarifies: “This was a long time ago, when there weren’t many silicones available, and while its adverse reputation wasn’t exactly unwarranted, its continued negativity is contagious.” But, he stresses, “if you look after your hair and cleanse it correctly, you shouldn’t have product build-up in the hair, so there really is nothing to worry about. As long as the right silicones are being used, you should only see a benefit in your haircare regime.”
So what exactly are the benefits of good silicone? “They help to reduce hair’s porosity, which in turn makes it less likely to absorb humidity from the air and styling tools,” says Sam Burnett, Creative Director of Hare & Bone. They’re also a blessing for frizzy hair with split ends, as “silicone can provide a protective layer acting like a shield, it can even sometimes lock in treatments and conditioners,” he tells me. But their real star quality is that they don’t interact with other formula ingredients and don’t affect hair fibres and proteins (e.g. keratin). In other words, “they don’t hinder other treatments that are often done to hair such as colouring, perming, etc.” explains Steve Shiel, Scientific Director of L’Oréal UK.
However, the crux of the issue is that this is only true for some silicones. Rob Forgione, Director, Bespoke Brands UK, urges caution: “Dimethicones are non-water soluble and turn the external coating of your hair almost into a drinking straw, like hard non-permeable plastic,” he warns me. “The hair becomes strangled, brittle, and is unresponsive to any haircare products or colour. That’s when you need ‘chelating’ – a professional deep-cleansing shampoo to remove the build-up and restore the natural balance of the hair,” he states. The silicones that you don’t need to sidestep include cyclomethicone: “This evaporates and won't leave build-up on your hair. It gives a silky, smooth feel and leaves wet hair with incredible slip. Equally, dimethicone copolyol is a smart choice for thin flyaway hair as it's water-soluble silicone and very lightweight,” says Rob.
It’s not just the type of silicone you need to keep a beady eye on but also the technology that goes into formulating it. Tresemmé, for example, has been continuously studying more than 2,000 types of silicone for over 30 years. “This way, we are able to target different hair needs and provide the right benefits” explains the brand's R&D team. Their latest breakthrough can be found in the new Keratin Smooth range, which cleverly harnesses silicone to smooth hair but allows for natural movability. How? Well, they’ve created nano-silicones. These are tiny particles that form a very thin film which “lubricates the hair fibre for ease of combing without weighing the hair down,” reveals the Unilever R&D team. They’re the equivalent of a sprinkle of sugar vs. a sugar cube: the latter weighs hair down, whereas an even sprinkle of silicone thinly coats strands, giving you that sought-after shiny slip. “We also exploit amino-silicone, which targets the driest areas of the hair fibre and then spreads to create an even coverage” the team reveals. Think of these as tiny magnets that cling onto the driest part of the hair first.
If that wasn’t enough, they also couple their silicones with cationic polymers. These polymers are positively charged and bind to the negatively charged areas of the hair surface to improve lubrication and therefore ease combing. If used in wash-off products, they will be removed at the rinsing stage as they are only needed during wet combing in the shower. If used in leave-on products, they will stay on the hair surface, allowing your brush to sail through strands without breakage. So while it pays to be a label nerd, it’s also wise not to jump on the "natural is cleaner and therefore better" bandwagon. In this case, the newly formulated silicones are perhaps not the big bad wolf of the haircare world, after all.

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