Is K18 Molecular Repair Hair Oil Worth it?
Hi my name is Paige and I’m a hair oil snob. No but really - I have fine, highlighted hair so it’s important for me to use a hair oil that’s nourishing and repairing but not so heavy that it weighs my hair down or leaves it feeling greasy. I’m also picky about scent, and even pickier about my budget. I try tons of hair products all the time, so something needs to prove itself to be extremely valuable for me to rave about it.
K18 is a brand I love but it’s expensive, so it’s not one I use on a daily basis. I have noticed more breakage around the roots of my hair (it’s giving Dill Pickles from Rugrats), so I knew I needed to find a high-quality oil that would work overtime to repair damage and reduce breakage, but wouldn’t weigh down my fine hair. K18 Molecular Repair Oil was the oil most recommended to me, and I finally bit the bullet and purchased a bottle last year. Six months of consistent usage later, I’ve really gotten to know the product.
For pros, cons, dupes, and whether or not I think the K18 Molecular Repair Oil is worth the price, keep reading.
k18 molecular repair oil review
how to use k18 molecular repair oil
You can use the K18 Molecular Repair Oil on damp or dry hair. I personally prefer to use it on damp hair, but here’s how to use it both ways:
On damp hair:
Start with 1-3 drops.
Apply from mid-length to ends.
I recommend giving it a minute or two to soak in before continuing on with your drying and styling routine so that you get the full benefits.
Optional: you can add a leave-in conditioner for extra protection, but the K18 Molecular Repair Oil also serves as a heat protectant.
On dry hair:
Start with 1-3 drops, but use less than you do with damp hair. I personally use just one drop, even though I have long hair.
Focus on the ends, as using this oil on dry hair is more of a finishing step than treatment.
Optional: if I have any leftover product, I lightly run my hands on the roots of my hair. This can be a little too heavy for some of you, but I have breakage at the root that I want to heal and it really isn’t that much/ greasy for me.
pros
Can be used on damp and dry hair
A little goes a long way - just 1-3 drops, so a bottle will last a while
Lightweight yet super hydrating; even fine hair can use this oil
Strengthens hair and repairs damage
Reduces frizz at two levels of the hair fiber
Adds shine
Also works as a heat protectant
cons
Very pricey - $27 for 0.34oz (travel size) or $65 for 1oz (full size)
Bottle sometimes leaks/ is easy to spill (wish it were a pump instead of a dropper)
is k18 molecular repair oil worth it?
It kind of pains me to say this because it is so expensive, but K18 Molecular Repair Oil is 100% worth it. If you have lots of damage, color/bleach your hair often, or heat style your hair regularly, this is a hair oil you want in rotation. It has genuinely reduced breakage and frizz for me, and I’ve noticed a difference after using it consistently over the last few months (finished a mini bottle and onto the regular).
There are so many hair oils out there, and they’re mostly all going to provide shine and glow to your hair, but it’s rare to find an oil that goes deep into the follicle to heal your hair from the inside out, and K18 does that. The scent is mild and true to all K18 products it’s a little fruity, but not overpowering. My boyfriend prefers woodsy/ leather scents and he likes the smell of this oil, so I think it’s pretty universal.
As far as usage goes, a little does go a long way with the K18 Molecular Repair Oil. I like that you get all of the good benefits (shine, less frizz, healing damage) without your hair feeling greasy or weighed down like with some other oils. You can use this oil on damp and dry hair, but I prefer to use it just on damp hair as it feels more nourishing. For dry hair, I prefer something cheaper since I see it more as a finishing step than treatment.
Another tip: don’t use this as a pre-wash treatment; use a cheaper oil instead. I prefer to use this after I wash because my hair absorbs it better and I feel like I get the most out of it that way. You also get those benefits locked into your hair until the next time you wash (but use a different heat protectant in between if you style your hair multiple days in a row).
Truth be told, I’ve adjusted my budget to repurchase this hair oil and get a cheaper hair mask - it allows me to not overspend, and my hair looks better than before.
Another option: get the travel size to start with like I did. It may cost more per ounce like a lot of travel/ trial sizes do, but sometimes spending less up front is more feasible, and you get to really test the product out before investing.
k18 molecular repair oil dupes
K18 products are highly concentrated, so a little goes a long way and the bottles will last a long time, but you still have to pay quite a bit up front. Doing the math, a full size bottle of K18 Molecular Repair Oil is $65 for 1oz of product. Breaking the math down per ounce, these are some of my favorite dupes:
Moroccanoil Treatment Hair Oil - The pricing seems similar/ still a little expensive, but this is an excellent dupe for the K18 oil, and the scents are pretty similar for both. It costs $50 upfront, but breaks down to $14.7 per ounce (K18 is $65 per ounce). This is a thicker oil, and I’d recommend only using it on damp hair, unless you want to do a prewash treatment as it will make dry hair greasy. This also works as a heat protectant, and the shine it gives you is unreal.
Dae Prickly Pear Hair Oil - I find Dae to be really hit or miss, with some products being perfect (Cactus Fruit 3-in 1 Styling Cream) and others falling short (any shampoo or conditioner). The Prickly Pear Hair Oil has been in my rotation for years and I’ve repurchased it quite a few times. If you want the shine that the K18 Molecular Repair Oil gives you, I think Dae’s hair oil is an excellent dupe. At $38 for 1.7oz, it comes out to $22.35 per ounce - about a third of the price of the K18 oil. Prickly Pear Hair Oil is formulated with prickly pear seed oil not just to give it a beautiful fruity fragrance; it also hydrates, nourishes, softens, and adds shine, so you get some of the nourishment with this oil that you do with the K18 oil.
Olaplex No. 7 Bonding Oil - A little pricey as well $30 for a 1oz bottle) but this is a pretty close dupe to the K18 oil. It nourishes, provides heat and UV protection, reduces frizz, and helps with bonding to reduce damage. It’s lightweight yet effective, adds tons of shine, and great on all hair types. I will say that Olaplex products tend to be polarizing; they’re either perfect for your hair or add damage. I’ve heard both sides from friends, so I recommend strand testing for a bit before investing in the entire line (and why I list other dupes before this one).
FAQs
is k18 molecular repair oil a heat protectant?
Yes, the K18 Molecular Repair Oil works as a heat protectant up to 450°F (232°C).
is k18 molecular repair oil good for extensions?
Yes, you can use K18 Molecular Hair oil with tape-in, sew-in, and clip-in extensions. Just make sure to avoid applying the oil directly to the adhesive or keratin bonds, as the oil can cause them to slip.
is k18 molecular repair oil good for low porosity hair?
Yes, K18 is one of my favorite brands for low porosity hair as their formulas are lightweight yet highly concentrated and are designed to reduce protein-related damage. Their science-backed formulas are some of the best on the market. Where other brands want your hair to look good, K18 wants your hair to feel good and be good, so I highly recommend their products for low porosity hair, especially the K18 Molecular Repair Oil.
is k18 molecular repair oil color safe?
Yes - I have highlighted hair and unlike some other hair oils, the K18 Molecular Repair Oil hasn’t caused any brassiness or fading. As far as haircare brands go, K18 is one of the best for color-treated hair.
k18 molecular repair oil vs olaplaex oil
I listed it above as a dupe because they’re both really similar. K18 Molecular Repair Oil is more expensive (essentially double the price). Both have similar weight and texture while also providing heat protection, add shine, reduce frizz and repair damage. Olaplex No. 7 Bonding Oil also offers UV protection, but your hair either loves it or hates it. My mom has thick grey hair and loves it; I find that it’s so-so for me, and my friend with curly hair swears it made her hair even drier than before. I recommend doing a strand test for a week or so to be safe.
k18 molecular repair oil vs kerastase oil
Kerastase sells a few hair oils, but I’d say their Elixir Ultime Refillable Hydrating Hair Oil for Shine is most similar. Both the Kerastase and K18 hair oils provide heat protection, add shine, reduce damage and frizz, and are lightweight yet hydrating oils. K18 is more expensive; the Kerastase oil is $62 for 2.53oz ($24.51 per ounce; a little more than third of the K18 price). I loved the OG formula, but they’ve recently reformulated the Elixir Ultime Refillable Hydrating Hair Oil and it’s a little fussier and doesn’t give as great of results. I like that they’re moving towards sustainable refillable packaging, but it can be a little bit of a pain as well. Get one of the dupes I mentioned, or the K18 Molecular Repair Oil instead.