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I fell in love with K18’s product line to the point where I basically bought everything they make and started rotating it into my routine to see what actually hits and what doesn’t. Last time I shared my thoughts on K18 Detox Shampoo, and now I’m back with K18’s newest release: TripleBright Oxidation Defense Purple Shampoo.
Before this, I had mostly stopped using purple shampoos. I preferred focusing on hydration and overall hair health instead. My hairdresser never really pushed purple shampoo on me either, and honestly, my hair looked fine without it.
That being said, I’ve used enough purple shampoos over the years to know how they usually behave. Most of them don’t lather the way I want them to, which always bothered me a little. On wash days I shampoo twice, so if I used a purple shampoo, it always went in during the second round.
I also learned through experience that purple shampoo is one of those products where timing matters. You don’t want to rinse it out immediately, but you also don’t want to get distracted and accidentally leave it sitting too long either. Unfortunately, I learned this while singing an aggressively long song in the shower and ended up slightly lavender.
So with all of that in mind, this is what I experienced using K18’s Purple Foaming Shampoo.
My Hair Situation (Context Matters)
I didn’t wake up one day as a Blonde Asian. I eased into it.
I started with highlights. That turned into balayage, which eventually turned into scalp bleaching. Somewhere along the way it became more of a lived-in blonde that still keeps evolving. But at the end of the day, it’s still chemicals on my head, and damage happened.
I went from a natural level 2 to roughly an 8 or 9.
My hair is straight and coarse, but dryness mostly shows up at the ends instead of the scalp. Before I cut my hair, the ends tangled constantly.
That’s the baseline I’m working from whenever I try something claiming to repair, protect, or maintain blonde hair.
The Foaming Purple Shampoo Situation
K18 claims this shampoo not only neutralizes existing brassiness, but also removes mineral buildup while helping defend against future oxidation. I’m assuming that’s where the “triple” in TripleBright comes from.
The most interesting thing about this product to me was the foam delivery system. One of my long-standing issues with purple shampoo is that it never lathers in a satisfying way. Sometimes it felt like it disappeared into my hair before I could even work with it properly.
I genuinely wasn’t sure if the foaming mechanism would help or just feel gimmicky.
A lot of K18’s products are marketed toward all hair types, but this shampoo is specifically intended for blonde, highlighted, lightened, silver/gray, or chemically processed red hair.
If your hair doesn’t fall somewhere in that category, I’d probably stick with K18’s regular shampoo and conditioner instead.
How I Actually Use It
I started using TripleBright immediately after buying it. After about six weeks, I settled into using it only when I feel like my color needs recalibrating.
At this point, I use it less frequently than Peptide Prep Shampoo. I mainly reach for it when my blonde starts looking slightly off to me.
I always shampoo first with whatever shampoo I’m using that day, then go in with the K18 Purple Shampoo second.
Now I need to publicly admit something embarrassing: I have a habit of shaking bottles before using them. DON’T DO THAT!
The shampoo inside the bottle is pretty liquidy, and the first time I used it I shook it out of instinct, uncapped it, and immediately created what can only be described as a purple homicide scene in my shower.
The nozzle is designed to foam the product as you pump it out, which is honestly part of what makes this product interesting in the first place.
The bottle recommends 1–3 pumps from roots to ends. I don’t always follow that perfectly, but I do think the foam helps distribute the product more evenly through my hair without it disappearing immediately.
Does it fully solve my “purple shampoos don’t lather enough” issue? Kind of.
Because it’s already foamed up, it sits on the hair more visibly instead of vanishing into it. On the flip side, because it’s pre-foamed, I sometimes feel like I’m frosting my head like a cake instead of shampooing it.
What I Noticed Over Time
After the first wash, I noticed a pretty significant difference. I honestly didn’t even realize my hair needed recalibrating until I saw the before and after photos side by side. My blonde looked brighter, cleaner, and less dull overall without looking icy or over-toned.
By the second week though, the effect didn’t feel as dramatic. Oddly enough, I think that’s proof the product is doing what it claims to do.
One of K18’s claims is that TripleBright helps defend against future brassiness. With older purple shampoos I used in the past, I felt like I needed them weekly because warmth crept back in quickly.
With this one, I don’t really feel that urgency.
The before and after photos also made me realize the changes are easier to notice side by side than they are day to day. When you see your own hair constantly, subtle shifts in tone are easy to miss until there’s visual proof sitting directly in front of you.
Who I Think This Works Best For
I can confidently say this works well on chemically bleached blonde hair. I noticed the clearest results after my first wash.
I also think this is best for someone who wants brightness maintenance without wanting purple shampoo to become an entire personality trait.
Is It Worth the Price?
The full size bottle is 4.2 oz and costs $39. Unfortunately, there’s currently no mini size available, so if you want to try it, you’re committing to the full bottle immediately.
Honestly though, with the foaming mechanism, I’m not even sure how well a mini would work.
For me, it’s worth the price because I don’t use it weekly. If I were blowing through this constantly, I’d probably feel differently.
Part of the reason I stopped using purple shampoos regularly in the first place was because they started feeling slightly trendy to me. I cared more about keeping my hair hydrated than aggressively micromanaging tiny shifts in tone.
Where It Fits in My Blonde Routine
This fits into my routine pretty naturally because I treat it more like a maintenance adjustment than a standard shampoo.
I specifically reach for it before events or during moments where I want my blonde looking a little brighter and cleaner.
If I had to choose between this and a traditional purple shampoo, I’d still pick K18’s version because the foam application genuinely works better for me.
The Grounded Verdict
I’m keeping K18 Purple Shampoo in my hair arsenal, but not in the way the brand probably intends. For me, this is more of an occasional correction product than a weekly necessity.
Ironically, the foaming format is what got me interested in purple shampoo again in the first place. I still don’t think purple shampoo is mandatory for blonde hair. I think it’s more of a bonus category product.
That being said, once this bottle runs out, I will repurchase it. Probably alongside other K18 products I already know I like anyway.
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