
According to Kérastase, the Extentioniste-line is like a workout for your hair! It’s made for those who want to grow out their hair long but experience shedding at the ends due to bleaching, hot tools, or brittle hair. My hair is finally at waist length but as my ends are turning about six years old there’s a lot of split ends and shedding happening that slows my growth and healthy hair look!
For some reason, I don’t remember, Kérastase came up on my radar. I remember using one of their hair masks that my mom bought like 20 years ago, and that’s about all of my experience with the brand. I think it’s because there are so many new brands that have popped up, that I just wanted to go back to some of the old classics!
Kérastase used to be considered a high-end expensive brand, but nowadays I’d say their products are more mid-range; not cheap but sort of affordable. Especially in Europe as it’s such a classic brand, many webshops compete in pricing. If you live in the US, it might be a different story.

Extentioniste Shampoo
The shampoo cleanses well without feeling stripping at all. Hair is left clean but still soft, ready for conditioner. But I was surprised at how much I had to take to get any real lather going. Before purchasing I watched countless reviews, and practically everyone talked about how concentrated Kérastase products are and how little you need to take. But I had to wash and rinse 3 times with this particular one to get any foaming action! Or take a lot of it!
While I know and understand that no foam doesn’t equal no cleansing, I’m still bewildered by what everyone else was saying about Kératsase shampoos. Because I had to take more than I usually need I ran out of shampoo before my conditioner! Which was annoying. Usually, it’s the other way around.
Other than it wasn’t as concentrated as told by others, I did generally like the Extensioniste shampoo. It’s a clear gel, and usually, I opt for more pearlescent/creamy shampoos that feel more conditioning. I wouldn’t say that it stimulated my hair to grow faster or anything like that, but my hair and scalp felt healthy. And I did notice less hair shedding from the roots when washing.
Extentioniste conditioner
If shampoo is there to make sure you have a nice ground for growth, conditioner is there to take care of what’s already grown out. The Extentioniste conditoner is supposed to ease detangling and seal split ends. It contains maleic acid that’s unique for the line, which works similar to other bonding products – it’s just more temporary. And this is mostly why I got interested to try out this line and see if it would have any real impact on my split ends.
Now, I wish there was a travel set with the masque instead of the conditioner. I had some thoughts that the conditioner would be a bit too light for me, and my feelings were right. It’s not a bad conditioner though. Just for me personally, the masque would’ve been perhaps a greater fit as my hair tends to frizz and lean on the dry side. But overall, it left my hair silky smooth, just could’ve done with a little bit more hydration.
For it to work its magic you really need to give it the recommended 3-5 minutes. But unfortunately, I did not see much of an improvement on my split ends using this. I was still shedding a lot from the ends when combing. And I do believe it mostly had to do with me not having the Exentioniste thermique blow dry primer, as conditioner can only do so much. At least when it comes to split ends, I think the best way to combat shedding from the ends is a combination of a good hair conditioner/mask and leave-in. You can’t just rely on your conditioner.

Extentioniste Scalp Serum
So this was actually the first product I got from the line and I didn’t get to try it in combination with the shampoo and conditioner before using it up. But while using the wash duo I’ve been using the Initialiste scalp and hair serum which is very similar (I’ll do a separate review on it). It’s hard to say anything about these hair serums as you do really need to use them for a couple of months, at least 6, to truly frame an opinion and see real results. If someone says their hair feels thicker after 1-2 weeks it’s mostly placebo or temporary thickening agents…
First of all, the Extensionist serum is 50 ml, and it lasted me about 2 months with 2-3 times use/week. I used about 3-4 full pipettes after almost every wash with a focus on my temples. Personally, I find it pretty expensive for only lasting that short amount of time. The Initialiste serum is 60 ml and so it is lasting me a bit longer and it’s about the same cost.
Because I only used it in such a short amount of time it’s hard for me to put any words on the results promised. The serum itself felt great applying, I would recommend applying it on damp hair straight after showering. The scent is fresh but not overpowering. It felt like the results weren’t visible until a month after I finished the Extensioniste serum and got the Initialiste serum. And so I’m unsure which serum did what and if the other is only conditioning further what was done by the first serum. They both have very similar bases and ingredients, just a bit different actives.
Either way, I can tell you that something is working! I’ve dabbled with hair serums in the past, but this is the first time I actually see baby hairs at the temples where I wanted some growth the most! So I’m hugely impressed but I do think the serums are quite pricey. Overall, I don’t think it matters which Kérastase scalp serum you use, I’m on a quest to try all of them lol. My only concern is that I didn’t see a great deal of less hair shedding from the roots, but that’s probably not what the Extentioniste serum is for. So I’m going to try the Genisis serum next.

Resistance Ciment Thermique
In my travel set I got the best selling Ciment Thermique instead of the Extentioniste Thermique, which was a bit disappointing. But I had heard many good things about this one and as I just started to blow dry my hair more during winter I tested it out.
The Ciment thermique is a heat protectant for very damaged and overprocessed hair. It’s supposed to reduce breakage, smooth hair and cut down the drying time. When it comes to heat protection I’m a bit confused as up to what degrees it actually protects from. Some sites, and on their own, says 180C. While I’ve seen some American sites and influencers say 240C. I mean, there’s a huge difference in protection. I personally wouldn’t use this with a flat- or curling iron. The information isn’t very clear with this particular product.
Now, I don’t know if it’s the winter dry air affecting the product or what, but I can’t see how this is a favorite among so many?! The big plus is that it cuts the drying time by a lot! I mean, as soon as I put it in my hair, my hair rapidly dries to the point of no return. It’s basically too effective and dries out my hair completely compared to other leave-ins. My hair is left quite frizzy, frail, and not at all shiny. The only positive out of that is that it’s got a lot of 90’s volume, but at the cost of lots of frizz.
I don’t know, perhaps I have another standard of how I think hair should feel and look like. But this blow-dry primer basically undid all the moisturizing masking I did in the shower. And this product is supposed to be for damaged hair?! Here’s the other thing, I see a lot more split ends when I use this… This must be because it dries the hair so quickly the cuticle gets exposed again instead of staying sealed?
Either way, this one sadly did not work for me. At. All. Like, I’m wondering if I got a bad product or something? The good news is that I later bought the Nutritive Nectar thermique, which is supposed to be a heat protectant for dry hair (that protects up to 240C). And that one works so much better for my hair! It doesn’t cut the drying process by 60% like the ciment thermique, but my hair is looking a lot less frizzy, shinier, and with fewer split ends. After that, I also bought and tested out the Kératsase Curl Manifesto Leave-In. And now we’re talking about a blow-out primer for textured hair! This one leaves my hair hydrated and smooth with no frizz when blowdrying with a round brush, up to my standards.
Summery
Overall, would I repurchase? I don’t think I would from this specific line. Maybe I’ll try the Extensioniste hair mask in the future to add as a supplement. But the shampoo and conditioner were a bit “meh” to me. Didn’t feel too much different from the drugstore more than the scent was more pleasant and it didn’t lather as quickly. I still want to try out more from Kérastase, but I’m not as hyped up about them as I was before. I thought I’d get shinier and softer hair, but honestly, I’ve had better. Could just be that this particular line wasn’t what my hair needed.
I didn’t know how many lines and products Kérastase offered until I looked them up. It’s a lot! A bit too much… But I’d like to explore the Genisis line, which is supposed to help strengthen hair both from the roots and ends. I experienced a massive hair fallout in early fall 2021, from what I believe was from my second dose of covid-vaccine. I went from having 9.5 cm hair thickness to 8 cm in just a month. So anti-hair fallout and regrowth hair care is very appealing to me at the moment.
If you’re looking for something similar to Extensioniste but cheaper, Redken Extreme Length is similar, with a conditioner containing maleic acid. As well as Elvital/Elvive Full Resist, which markets itself pretty much the same, “a workout for your hair”. It’s worth mentioning that Kérastase, Redken, and Elvital are under the same L’Oreal-umbrella and, therefore, not shocking to see similar products.