Editor's TipEditor's Tip

For added protection, use together with Kérastase Chroma Thermique.

Kérastase

Birchbox Breakdown

Apologies to Gehry, Libeskind, and all the other starchitects: Kerastase is giving you a run for your money—at least when it comes to jawdropping hair feats. The brand’s dual-phase serum transforms damaged hair by repairing its actual foundations—the fibers in each individual strand. Once those are fortified and healthy, the serum adds ceramides for smoothness and gloss. You’ll have a gorgeous, award-worthy coif.

How it Works

Instead of just piling shine enhancers on top of deteriorated strands, Kerastase’s two-part serum gets to the root of the problem—literally. Intra-Cylane and Pro-Keratin work together to reinforce and fill in damaged hair fibers. Then, ceramide seal the newly healthy strands and give them a sleek, uniform exterior.

How to Use

Squeeze a dime- to nickel-sized amount (depending on hair length) into palms and rub together. Run hands through damp or dry hair from mid-length to tip. Blow dry or flat iron to seal each cuticle.

More for You!
  • Free returns within 90 days of purchase
  • Extra samples and gifts in the Bonus Shop

Product Reviews & Sample Feedback

9 Reviews
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Most Helpful Customer Reviews

The Best Hair Product I Have Ever Used!
Purchased

I cannot rave enough about Fibre Architecte! My hairstylist introduced me to it, and I am addicted. It makes my hair feel smoother and softer than it ever has, and tames flyaways and frizz on humid days. It smells great, and it truly makes my hair feel like I just had it done at the salon. It's expensive, but totally worth the price. A little goes a long way. My highest and most enthusiastic recommendation!

5
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Love it!
Purchased

I have been using this for a few years now and keep it in constant supply so I don't find myself at the bottom of the bottle without new stock on hand. It is essential for my hair which is wavy and frizz prone in humid weather. It smooths our my locks and helps protect it from the heating elements I use on a daily basis. It's a little mnore expensive than other serums but well worth it. You don't need much (I use 2-3 pumps and I have medium to long hair) and that lasts me about 1 1/2 to 2 months. Great investment for your hair!

5
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Love the product, but tiny size
Purchased

I love the product, I feel like it gives my long hair the extra tlc it needs, leaving it soft and smooth. I am a Kerastase devotee, and am used to their styling products being the typical 4.2 ounces. I wish I had paid attention to the size when I ordered. This bottle is tiny and its expensive!!!

3
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Great for split ends

I have bleached, damaged hair. When I use this it seems to repair my split ends and gives me a much smoother look.

5
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Not totally sure it worked, but really liked it

I have long, bleached hair, so it wasn't in the best place to begin with. I used this stuff completely in about 6 weeks. My hair seemed manageable and definitely shinier after I was through, but I can't tell that it "repaired" anything, as I also had my hair trimmed twice during this period, and was using other hair care products. I'm not sure it's worth the price, but if it were cheaper, I'd probably keep it in my rotation.

4
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Love this!
Purchased

This product has transformed my dead ends! Every time I use it it looks like I just got a fresh cut!

4
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I'm on the fence

I'm still using this and I can't tell if my ends are improving because of regular deep conditioning. So far so good, and the smell isn't over powering.

4
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Tames flyaways and makes hair silky
Purchased

I have long, bleached hair. I add this product midway through a blowdry - to the ends only. I think it really tames the flyaways and makes my ends look healthy.

5
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You're going to get addicted
Purchased

I love this stuff I am from the city in TX and with all the damage in the summer from the pool and sun my hair needs this. I have long hair so split ends have always been an issue, but with this stuff my hair has never looked healthier. I have always been a big fan of Kérastase products but this one is one of the BEST!

5
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