K18’s Volumizing Spray Is the Only Product That Makes My Fine, Thin Hair Look Fuller

As a beauty editor, my email inbox is inundated with offers to test new hair products. But I almost always decline. My hair is extremely temperamental. My fine, thin strands look weighed down and greasy no matter what I try, even volumizing products often fail me. So when K18 launched the AstroLift Reparative Volumizing Spray, I thought meh. Well, until I tested it and quickly reversed my less-than-enthused statements.

Unlike the mousses, creams, gels, and root lifter sprays I’ve used in the past, AstroLift gives my hair fluffy, soft volume (like a ‘90s blowout or, my forever hair muse, Sabrina Carpenter). There’s no crunch, grease, or sticky feeling. And it doesn’t just lift my roots. It actually makes my entire head of hair look fuller and as if I have way more strands than I do. Don’t forget, though, that it is also packed with K18’s proprietary peptide to repair damage as it plumps.

I started testing this formula just before it launched last year, and I’ve only fallen more in love with it over time. Keep reading for my full review, including all the details on how it works and why I’m fully a convert.

How K18 AstroLift Volumizing Spray works:

We already know and love K18 for their bond-building hair products—namely, the OG K18 mask (a Cosmo Readers’ Choice Award winner) and their sulfate-free shampoos and lightweight conditioners. Last year, K18 launched its first-ever dedicated styler: AirWash Dry Shampoo, which became an instant favorite among the Cosmo beauty team (FR, I use it every other day). And AstroLift isn’t all that different in ethos. It’s the brand's first-ever styling spray that both volumizes and repairs damage at the same time.

How? It’s loaded with K18’s patented peptide blend, a combo of 123 amino acids, which helps strengthen hair and repair broken bonds at the molecular level. But it also helps make your hair look bouncier, lifted, and fuller—without making it feel stiff or sticky.

It’s officially available on K18’s website and Sephora.com if you wanna buy it now. But if you need more convincing...

Try K18 AstroLift Yourself

My review:

About my hair:

Without any product, my hair will simply sit flat against my head. Like, there is no bounce, no volume, no fluff. Nothin’. I have very fine hair that errs on the thin side (curse my teenage years of constantly changing my hair color). But the biggest thing with my fine hair is how greasy it gets from even the lightest-weight products. Sometimes even a dry texture spray will make my hair look shiny. So I’m all about formulas that won’t weigh my hair down and don’t cause buildup either. But I also heat style a considerable amount and have eight-month-old highlights that I’m growing out rn, so any bit of repairing and strengthening I can get with my products, I’ll take.

My experience:

The best part about this spray is that you can use it on wet or dry hair. However, I was hella skeptical that my fine, greasy-as-hell hair could handle being spritzed with something dry. So, for the first few tests, I only sprayed it on damp hair after showering. Don’t be afraid to really go hard, too. I spritzed my whole head (roots to ends) probably about eight times to really test if this would weigh my hair down or make it feel tacky. Then I’d blow-dry with my Dyson Airwrap to help set the formula. You don’t have to use heat to activate it, but it definitely adds more volume when you do, per my testing.

Once I felt comfortable using this on wet hair, I started spritzing it on my dry hair to zhuzh it up on day two before curling my hair. I wasn’t as liberal with my sprays on dry hair to avoid adding too much product. But more on this below.

When I first started testing last year (before I dyed my hair red, lol).

My results:

When I use this on wet hair, I cannot believe how soft and smooth my hair feels. IDK if I’ve ever used a volumizing product that’s made my hair so ~touchable~. If you could see me rn, I’m lovingly running my fingers through my hair in awe at how good it feels. But it also seriously fluffs up my hair. It looks like each hair strand is just a little more plump, which definitely makes my hair feel a bit more lush and healthy. Do I suddenly have a gigantic bun on top of my head? No, but my ends don’t revert to their usual stringy, thin look. My hair looks so good, it’s simply an added bonus that it’s helping repair damage at the same time.

But what shocked me the most was how great this formula is to my second- and third-day hair: It brings some new life when I spray it on my dry ends on those days. It leaves no residue on my hair once I brush through while adding some extra bounce to my hair. It’s especially good when I pair it with K18 AirWash Dry Shampoo...a match made in heaven.

Final verdict:

Sooo, K18 AstroLift is kinda like the volumizing product I’ve always been searching for. It adds fullness to my roots and ends while also hydrating and repairing my hair so it feels soft and smooth. It’s definitely expensive for a styling product, but it took me two months to use up a tiny travel-size sampler, so I know a full bottle would last a long time, even though I’m pretty liberal with my spritzing. And it basically acts as a couple of steps in one by conditioning, volumizing, and repairing. If you think about it, I’m actually saving money. Girl math!

SHOP K18 ASTROLIFT HERE

Why trust Cosmopolitan?

Beth Gillette is the beauty editor at Cosmopolitan with more than seven years of experience researching, writing, and editing hair stories that range from hair bonding treatments to red-light therapy devices. She regularly tests and analyzes hair products for efficacy, while working with the industry’s top hairstylists and trichologists to assess new formulas and brands.