The £10 treatment that can finally tame your frizz

On my last bad hair day, a waitress at a restaurant I was at pointed to my head and exclaimed: ‘I’m having a perm because I want hair like yours!’ I asked her what medication she was on.

Granted, big hair like mine is supposedly back in fashion, but that doesn’t make me feel any better about the lifelong battle I have fought with my curls. On its rare best days, it forms ringlets. On its worst — most — days it’s a coarse, frizzy mess that should have its own postcode.

Plus, fashion or not, I love the sleek look and, having blow-dried it straight for most of my adult life, I’m convinced that my personal and career successes have been helped along by having long, straight and very controlled hair.

Trouble is, the tools commonly used to create this look, from blow dries to straightening irons and keratin blow dries (chemical salon treatments), cause damage.

Probably the biggest repair breakthrough to date has been Olaplex, which fixes the bonds holding keratin proteins together following heat and bleach damage. Still, it adds about £20 and 20 minutes to your salon visit, and that’s before you follow up with the take-home version which costs £26.

Since I have been blow-drying almost daily for years, using straightening irons a few times a week, and had about five keratin blow dries in about three years, my hair is a brittle, breaking and utterly roasted disaster.

About 12 months ago, my hairdresser gave me an ultimatum: stop the keratin treatments, throw out the straighteners and blow-dry only once a week or less, or we’re over. That’s not a relationship I wanted to jeopardise, so I complied. After cutting off the damage — about two inches — I have been able to grow my hair and wear it curly more often.

But if someone offered me an undamaging treatment that promised to turn my hair into a flat, sleek, shiny mane that didn’t become a ball of fuzz as soon as I went outside, I would bite their arms off.

Well, high-end hair brand Kerastase is promising just that. Its new K Water is an in-salon treatment that protects hair from the humidity that causes frizz and ruins hard-won blow-dries.

And then there is the price. I have to practically remortgage my home to keep myself in Kerastase shampoo and conditioner, but I pay up as they are backed by incredible research. K Water, however, costs around £10.

So what causes frizz, anyway? Two words: damage and moisture. ‘When hair is damaged, it has gaps in its protective surface which means tiny water molecules [from humidity and rain] can enter and play havoc,’ explains Kerastase’s scientific adviser Atoshi George.

‘This changes the hair shape and the way it falls, making it swell and create stress on the outer part.’ Think frizz, frizz and more frizz.

K Water treatment is touted as a ‘raincoat for the hair’, claiming to form a shield to protect against environmental elements that cause frizz. Its lamellar technology, borrowed from skincare, delivers repairing amino acids and proteins only to areas that need it. It’s also silicone-free — I avoid silicones as they can make my hair frizz.

Until now, products to repair damaged, frizzy hair usually came in the form of heavy conditioning masks, which can weigh hair down — especially if it is fine, like mine.

But K Water is lightweight, says Atoshi, adding: ‘It was developed by looking at ways to ensure the active ingredients could be targeted to damaged hair without weighing it down.’ It detects gaps in the hair cuticle caused by damage and seals them. It’s a sort of temporary top coat (it washes out with your next shampoo, but at £10, who can complain?), and my Hair Holy Grail.

It works almost instantly. My hair is shampooed twice with Kerastase Discipline Bain Fluidealiste, which can help calm frizz. Then drops of K Water are applied onto my wet hair, massaged in, and brushed through using a Tangle Teezer for about two minutes.

‘We put the K Water on saturated hair as it travels across the hair shaft via water and goes to the most damaged areas to bond them temporarily,’ says Georgie Perkins, a stylist at Trevor Sorbie in Bristol, where I have my treatment.

The K Water is then rinsed off, and I’m led to the blow-dry chair. I can immediately tell there is something different about my hair — it falls flatter and sleeker. But nothing prepares me for the final result. Without using straighteners or serums, the hair has the shiniest, smoothest finish I’ve ever seen.

Georgie blow-dries it into sleek waves and I look like a completely different person.

After a normal blow dry, my hair would usually sport a halo of frizz by the time I got home. I can feel moisture in the air and I am dreading what might happen during my journey back to London and the 15-minute walk to my dinner date.

But I arrive with — wait for it — bouncy (yes, bouncy — my hair, for the record, has never bounced) waves without a hint of frizz.

The next morning, though, is the real shock. The big waves have fallen out, yet I have frizz-free, straight, flat hair. I feel like I never want to shampoo it again.

So, while temporary, if you need guaranteed frizz-free hair, even if only for a special event or occasion, I would — hand on my now very sleek hair — recommend it.

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Kerastase K Water costs from £7-10 at selected salons. Find your nearest via salon-locator.kerastase.co.uk