Lucy has lightened, fine hair and regularly heat styles. “When I first tested K18, I used it twice a week for the first few washes as recommended, then dropped down to once a week. I have fine, colour-treated hair that’s prone to breakage and frizz from daily styling, so I was curious to see if the product lived up to its bold claims.”

K18 Molecular Repair Hair Mask review: Product Deep Dive

At the core of all K18 products is a clever patented peptide which (unlike traditional conditioning treatments that work to temporarily smooth over damage) works to repair broken keratin chains deep within the structure of the hair. These chains are essential for providing both strength and elasticity to hair, and when they’re damaged (by things including heat styling, bleaching and general environmental stressors like pollution and UV from the sun) hair can become brittle, frizzy and prone to damage – all things that none of us want. But that’s where K18 comes into its own, and by helping to restore those broken chains, hair gets a new lease of life as well as improved strength and resilience.

The hair mask itself has a lightweight, creamy texture that feels luxe without being too heavy – meaning it won’t weigh finer hair types down, and the real key is to ensure you’re using it the right way – which is where things can get confusing, but it doesn’t have to be that way, trust me.

Unlike traditional masks, K18 Molecular Hair Repair Mask doesn’t need rinsing out, and instead it’s best applied to towel-dried, freshly-shampooed hair. How much you use depends on the length and thickness of your hair. Shorter, finer hair types should just use one pump, and for longer, thicker hair types, two pumps should be enough. Just remember less is always more – we definitely learnt the hard way with my first few uses.

Then, before you apply it, spend a couple of minutes working the product into your hand to form a thick white paste – it’s important that you don’t put it into your hair until it’s reached that sort of consistency. Once it’s ready to apply, start at the ends of your hair and pat the paste on, working upwards towards the mid-lengths and then to the root. Leave it to work its magic for around four minutes and then you can brush your hair through before applying your usual styling products and drying as normal.

The other thing to note is that you should use it in this way for between four and six washes (depending how damaged your hair is) and then you can drop down to once or twice a month, or as and when you feel like your hair needs a treatment.

Courtesy of brand

K18 Leave-In Hair Mask

K18 Molecular Repair Hair Mask review: GLAMOUR Road Test

Georgia: If we’re talking numbers, my last hair appointment was 10 months ago. I’ve been consciously trying to grow out my natural colour (a moment of silence for me growing out back-to-back bleach highlights), and when I finally caved and booked in for a refresh – to softly blend my root regrowth – my hairdresser actually did a double take. She told me my hair looked noticeably thicker, glossier, and that she could see regrowth in areas that had once been snapped and frazzled.