KERAZUL Keratin Treatment: My Honest 3-Month Test (Before & After)

Last November was when I first seriously thought about getting a keratin treatment. I was walking through the drizzle from my flat in Hamburg to the U-Bahn one morning, and before I'd even reached the first corner I could feel it on my scalp: that faint prickle of my hair starting to lift the moment there's moisture in the air.

In a bakery window I caught my reflection — and there it was again. The fringe I'd spent ten minutes straightening was already curling up. The rest stood around my head like a little cloud. My name is Lena Sommer, I'm 34, and I've been fighting wavy, frizz-prone hair since I was a teenager — and in a city where it feels damp 200 days a year, that's a daily battle.

And honestly, it stopped being just about hair a long time ago. It was about losing 30 minutes in front of the mirror every morning, only for it all to be undone by the first gust of wind. It was about plans I'd cancelled because the forecast said rain. If you have wavy, frizzy hair, you know exactly what I mean.

If you're reading this because you googled “kerazul reviews” and want to know whether the stuff really lives up to the hype: I was in exactly that spot. So I'm writing this as honestly as I can — everything that was good, and everything that annoyed me.

“Maybe KERAZUL really is different …”

I was skeptical all the same. Over roughly 20 years I'd tried just about everything:

• Countless drugstore products and anti-frizz serums that lasted a few hours at best.
• A flat iron I used almost daily for years — until my ends went brittle and straw-like.
• A keratin treatment at the salon for around 250 euros, where the formaldehyde made my eyes water and I sat in the chair with the window open.

None of it changed my hair for good.

Still, KERAZUL wouldn't let me go. On two forums and again and again on TikTok, I came across reviews that sounded suspiciously convincing: women with a hair type like mine, describing how their hair stayed smooth for weeks — even in the rain.

So I did my research. KERAZUL advertises its so-called KeraSmooth³ Technology, which is meant to do three things at once:

• fill the hair structure from within so it absorbs less moisture,
• form a kind of invisible protective layer that keeps out rain and humid air,
• and add shine and smoothness with nourishing oils, without weighing the hair down.

That's exactly where other products had always failed me — they could only ever do one of the three. So a few days later, one evening, I ordered the complete set — the keratin treatment plus Clarifying Shampoo, Smoothing Shampoo and Conditioner — for around 120 euros. Two days later the package was at my door.

How the application really went

On a Sunday soon after, I cleared the afternoon, lined up all four bottles in the bathroom and got started. Up front: the application is far more involved than anything else you do with your hair. If you have no patience for that kind of thing, be honest with yourself.

• Step 1: Wash your hair two to three times with the KERAZUL Clarifying Shampoo so there's really no residue left.
• Step 2: Blow-dry it completely.
• Step 3: Apply the treatment strand by strand and comb out any excess product.
• Step 4: Let it develop for 20 minutes.

And now the part the ads like to leave out. During the processing time my hair felt sticky and gummy, and there was a smell in the air — sweet and chemical, a bit like a nail salon. I had to throw the bathroom window open. The maker says there's no formaldehyde in it, but the process is far from odourless.

After I'd applied it, my hair looked matte and dull and clumped together in strands. I just stood there thinking: “Great, more money for the next disappointment.”

• Step 5: Blow-dry the hair completely again — with the treatment still in it.
• Step 6: The most important step, sealing. Go over each single strand about five times at 220 °C with the flat iron.

While straightening, the smell got even stronger: with every pass a little cloud of steam rose up, along with that warm, sweet scent. At some point my arm ached, and I was honestly relieved when the last section was sealed. All in all it took me just under two hours.

Right afterwards my hair still felt a bit straw-like. I was close to writing the set off as an expensive mistake.

The real turning point only came two days later, at the first wash with the KERAZUL Smoothing Shampoo and Conditioner.

When I blow-dried my hair afterwards, I could hardly believe it: silky smooth, shiny, and it just fell softly over my shoulders. No frizz, no straw feeling. For the first time in years my hair looked like I'd just left the salon.

My update — how it looks after three months

I'm writing this part now, a good three months later. And the effect has genuinely survived the Hamburg winter, with all its rain and drizzle.

I used to style forever in the mornings. Now I wake up, run a comb through once — and it sits. On one especially muggy January day, when normally every single strand would have rebelled, I walked to work through the rain with smooth hair. That was the moment I was finally convinced.

What I love most:

• My hair shines more, breaks less and feels stronger.
• It dries noticeably faster and looks smooth straight away — with no restyling.
• I save a good 20 to 30 minutes every morning.
• And I leave the house again without checking the weather app.

But — and this matters to me — it is not a permanent straightening. After about ten weeks I noticed my natural wave coming back at the roots, and a little frizz returning on the dampest mornings. KERAZUL doesn't remove the curl for good, it smooths and tames it for a while. Depending on how often you wash, the effect lasts roughly three months, then it slowly fades.

For me that's completely fine: even in its “fading” state my hair is still far smoother and easier to manage than before. I'm already planning my second application — this time I know what to expect.

My verdict: who KERAZUL is for — and who it isn't

Would I buy it again? Yes, without hesitating. If you have wavy, frizzy or frizz-prone hair, fight the humidity every morning and are willing to invest two hours once, then KERAZUL is the best thing I've tried in years.

But to be honest, it's not for everyone. If you expect a permanent, poker-straight result, you'll be disappointed — the effect lasts months, not forever. If you have no patience for a two-hour Sunday, or you're sensitive to smells with no window to open, better leave it alone. And if your hair is naturally straight and fine, you simply don't need it.

As for the price: a keratin treatment at the salon easily runs to a few hundred euros — and has to be redone regularly. The complete KERAZUL set was a fraction of that and gave me a result at home that, for me, is at least as good and lasted over three months — less than a single salon visit would have cost me. In the end it was the many good reviews and, above all, the look in my own bathroom mirror that convinced me; if you're standing exactly where I was back in November, I'd try it once in your shoes.

After three months of smooth hair through Hamburg's endless rain, I'd do it again in a heartbeat.

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