K18 Just Launched A Hair Oil – & R29 Editors Tried It First

Every once in a while, a brand gets so big, so fast that you don’t even remember what it was like before Sephora stores and salons carried it. K18 is that brand. Entering a space whose only recent occupant was Olaplex, K18 skyrocketed to fame with the launch of its hero treatment mask, more specifically its ability to shield strands during bleach and colour services, in addition to repairing damaged hair. To call it a magic wand for your hair is an understatement.

The brand has slowly rolled out companion products to round out the K18 system (these include two shampoos: a detox and everyday formula), but its latest launch is quite possibly the most exciting yet. A weightless yet potent hair oil.

To see how K18's new product drop fared, we enlisted three Refinery29 editors with three very different hair types to put the product through the paces. Keep reading to see our real-deal reviews. [Editor's note: K18 oil will be available in Australia as of the 1st of May 2023. ]

"As I’ve written about before, hair oil is one of the very few hair products I use on a regular basis. From hydrating to smoothing to adding shine, no product in my styling routine works as hard as oil does.

"Several friends of mine swear by the brand’s signature treatment — if I had a nickel for every time I’ve seen K18 name-checked by salon colourists for maintaining hair health during major colour services, like bleaching.  While my brunette highlights are very low maintenance (which is just how I like it), I’ve been on a hair growth journey as of the past few months, and K18’s hero ingredient, a proprietary peptide complex that helps reverse damage, is rumoured to be liquid gold for your strands. Needless to say, I was excited to try this stuff out.

"Like most hair oils, the texture had a good amount of slip and was clear in colour. Per K18’s publicist, I was advised that a little goes a long way with this stuff since it’s so concentrated. After I showered and washed my hair (which I do two to three times per week), I towel-dried with my Aquis before dispensing four or five drops of K18 hair oil onto my hands and spreading it through my fingers. Focusing my mid-lengths to ends, I finger-combed the oil into my damp (not dripping wet) hair and did a little scrunching to revive my wave pattern. I'm not exaggerating when I say that my hair air-dried to frizz-free perfection, and it felt so soft, healthy, and shiny. A lot of oils tend to weigh down my thick yet fine hair, but this one was truly a weightless wonder. Consider me hooked."
—Karina Hoshikawa

"I’ve been paying particular attention to my hair care ever since I got a perm. Don’t get me wrong, I’m absolutely in love with the results, but it has fried up my hair substantially. Instead of just conditioning my hair, I’ve also added an extra step of oiling my ends before using my hairdryer with a diffuser attachment.

"I really liked how this K18 hair oil left my hair nourished while remaining practically weightless. There is no sense of greasiness — unlike other heavier oils I’ve used, where I had to immediately wash my hands after — and it added some shine to my tresses. Since the texture is so 'barely there,' the difference is a lot more noticeable when I use my blow-dryer afterward. My hair feels softer and looks more lustrous even after blasting the blow-dryer on high heat, thanks to the product’s built-in protection. I’ve noticed that my hair even air-dries a lot faster with the oil on, which is a nice bonus. It also tames any morning frizzies like a dream. I’ll be turning to this new discovery regularly to amp up the possibility of a good hair day."
—Venus Wong

"I'm not much of a hair product girl, so adding an oil into my nonexistent hair-care routine seemed unnecessary, but I've been proven wrong. After washing my hair, I let it air-dry about 70%, added a few drops of oil to the middle/ends of my hair, and blow-dried it the rest of the way. Initially, I noticed my hair was much less frizzy and puffy after using my hairdryer. My hair also stayed soft and remained cleaner looking (if that's possible?) for much longer than it normally does — I literally went on two flights, had my hair in slick buns, etc., and it still looked pretty fresh and smooth after all of the plane naps and hair-tie dents."
—Kate Spencer