I was sceptical about this product at first but as a huge Kerastase fan i had to have it! I have dry/thin ends and after a few weeks of using this stuff on them they definitely feel in better condition and fuller. This is really expensive for the amount that you get but I would recommend it. One thing I don't like is the packaging, it looks quite nice but you have to push the pump in exactly the right place to get the right amount of each serum, plus you can't see the actual product through the packaging so can't tell how much is left.

In spite of the painfully absurd price tag, I cannot rave enough about this product. It has saved my color treated, baby fine, damaged hair. Yes it is expensive, but it smooths my hair without making it look greasy or weighing it down, it softens and smooths gummy, damaged sections without any negative results I usually get with -cone based smoothers. Nothing permanent or lasting but prevents breakage from wear and tear. My hair would have broken off and fallen out by now if it weren't for this. I use after beginning to blow dry to smooth out sections that cannot take the brushing. I use 1-3 pumps for fine thin hair, I can see burning through this if you're dealing with coarser hair. I am waiting on my back-up bottle of this--one for purse, one for home. Seriously, that's how much this has saved my damaged hair.

I am mixed on this product. I love the smell of this line so that's a huge plus and I think it really works well..however, I have to use so much of it to really notice anything and I am afraid to use the whole bottle in just a few uses!

Its a bit costly for how much I have to use but otherwise I really do like it.

I don't know if my hair is just impervious to any type of treatment, but this did nothing for my hair. I used it after i blow-dried my hair, and worked from mid-length to ends. I then ran a flat iron over it, and my hair looks just like it always has: Dry, brittle, damaged. I even used it in conjunction with the Ciment thermique. I dont understand.

Absolutely fantastic product! I applied this to wet hair before flat-ironing it and the glossy shine/silky feeling was brilliant! I highly recommend and will re-buy.

Yeah this product makes my lenghts shiny... My hair is very long, my ends get dry, and overall my hair is virgin of any kind of treatment or dye. The big problem for me is that it does make my skin very itchy along the neck (it does happen each time and only when I use this specific hair product !) and the strong smell is for me quite unbearable to the extend it gives me some headache!.... I am not a huge Kerastase fan but I like the Resistance line in general. I do not like this product as I find it very expensive and am not convinced on the impact it does really have on my lenghts in terms of making them stronger and healthier on the long run, and if your skin is quite sensitive, try it before you make this investment, I think it is overhyped (as is Kerastase in general!) and overpriced for what it really is, just chemicals, and what it really does.

OH HOW MUCH I LOVE YOU KERASTASE!

This serum is just so awesome. I have no words to describe how good it is!

I have no clue how it works on the hair but this is the only serum I ever used on my hair that actually seals the hair and the split ends, turning my dry bleached hair into silky smooth, glossy, healthy hair.

Nothing else I used from the vast amount of serums and products I ever tried, from very expensive to drugstore brands, has performed this "miracle" on my hair.

My only complaint is the packaging. Its good in itself but the pump is tricky. I was left with a bit of the clear serum but none of the transparent green with my first bottle. This was totally my fault so if you're thinking about buying this product, do make sure you're pressing on the pump evenly so the same amount of both serums is dispensed.

This product cost me about €35 which is very expensive, at least for me but I think it is totally worth the money if you have severely damaged hair. Plus a little goes a long way so it isn't a product you would be buying every 2 months as happens with cheaper serums.

So I am delighted to say I've found my HG! And will keep buying forever and ever :)

I too bought this one after reading the great reviews on here - and it's true - this is one amazing product. I had alot of blonde highlights put into my light mousey brown hair last summer. I have done that many times over the past 25 years but I guess due to my age? and too much bleach and too hot a blow dryer - my hair started breaking and got pretty dry. I have been using tons of hair repair treatments, taking biotin and vitamins, tried many serums and oils, but not until getting this did I finally find something to at least make ALL of my hair look actually HEALTHY again. I realize the damaged sections still need to grow out and/or be cut out (no way) - but it truly makes my hair look beautiful. The only two problems I have with it are the packaging and the price. You really can't tell how much is left in the bottle. I used the entire container in about 3 to 4 weeks! Yes, I have long hair (between shoulder blades) but I had to use 4 pumps per usage. I had no idea I was almost out until one day it just pumped out nothing! So I actually cracked open the entire container and seriously those tubes - the white and green ones ? - were DRY. How could that be? was all that serum only in the TOP section and those things just a decoy to make you think there is product in there ???
And the price. Yeow. And yes of course I will buy it again.
In fact, I should do that when I finish typing this! lol.
But $41 for three weeks ? I could get a keratin treatment to last 3 months and it would average out to less if I used a groupon..
But those two issues aside - I am still giving this one a top rating because this truly IS an HG product.
(BTW, I bought the Cimente Thermique to go along with it and in my opinion? it's not remotely necessary. I've used CT in the past alone and think that the FA works way better without it... I'd rather spend my money on two bottles of FA than one of each!)

Naturally, my hair is very dark brown (almost black) wavy/curly and there is A LOT of it. But I straighten it with a blow dryer and straightnert and get it dyed (every four weeks) VERY light blond so as you can imagine my hair is extremely susceptible to damage. After almost a decade of not protecting my hair, I am now almost obsessive about hair care and this product is outstanding for dry ends. No product can ever "mend" split ends but this is the closest it can come. No longer are my ends rough, in fact it makes it silky to the touch. I use this after I blow dry and before I use my flat iron. This product has made a huge difference and I use only about a nickle size so its actually not too expensive because it lasts forever and actually works.

I have stick straight, fine and long blonde hair. Because my hair is fine, I give it a good blowdry at least a few times a week, curl it or roll it on a hot brush occasionally. Naturally, this has an effect on the state of my ends (and just to clarify, I define ends by all hair below the nape of my neck, not just the tips). I also try to grow my hair longer, so I love a product that will minimise the amount you have to get chopped off at the hairdressers. For that purpose, this product is amazing. It makes your hair incredibly smooth, shiny and healthy-looking. And doesn't weigh it down like sooo many other products out there. I can't feel there's a product there, it feels like someone just transformed my hair to its prettier, shinier self.

Now, I am by no means Kerastase devotee, I think their shampoos, conditioners and masques are way overpriced. But I must admit that they've got it right with the Resistance line of styling products. I love-love-love Ciment Termique and will recommend it warmly to ALL hairtypes. The Fibre Architecte is for dry/dull ends only. If you get your hair cut every other month and have natural shine, you will not need it, Ciment Termique will be just fine. But if you want to make your dull and dry ends look healthy, there is nothing better than this.

I give it 4 lippies only because I don't think it will suit as many different hairtypes as the Ciment Termique. If you're trying to decide between the two, I'd go for Ciment as my first choice, it's a more versatile product and half the price of this one.

I do want to add that you use shockingly little product with this, so I expect it to last me a year or so. Really, a SMALL pea-sized blop is enough for my ends.

Very pleased and will buy again.