Kérastase Blond Absolu Cicanuit Conditioning Leave-In Hair Serum (Overnight Treatment), 90ml
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Product description
The essentials
If you’ve lightened, bleached, or added highlights, your hair can feel softer one day and more fragile the next. Kérastase Blond Absolu Cicanuit is designed as an overnight leave-in hair serum, so you don’t need to fit another step into a busy routine during the day.
On paper, it’s a conditioning overnight treatment for lightened or highlighted blonde hair. It’s enriched with hyaluronic acid and an edelweiss flower ingredient, with the idea of hydrating and helping the fibres feel more “plumped” while you sleep. The brand also positions it around reducing breakage and protecting hair from friction—two very common issues for hair that’s been through chemical processing.
The main thing this product is aiming for is waking up with hair that feels easier to manage. The base description calls out soft, detangled hair when you get up, which is exactly the sort of practical benefit that matters if you’re prone to knots or tangles.
It’s not perfect, though: because it’s an overnight treatment, it’s only really worth it if you’re happy to commit to leaving it in. If you tend to wash and style first thing in the morning, the “sleep on it” approach may feel a bit inconvenient.
Key takeaways
This serum is best thought of as a pre-morning routine step for already-lightened hair. You apply it to dry or damp hair, distribute it from root to tip, then leave it overnight.
The friction and breakage angle is a sensible fit for bleached hair. Bleach can make hair feel rougher, and roughness often leads to more tangling and snagging—especially when hair moves around in bed.
Where it’s likely to suit you: if your main goal is conditioning support overnight and a calmer morning detangling moment, rather than a quick daytime fix.
Where it may fall short: if your hair is very fine, you may need to be careful with the amount used. Using too much leave-in product can leave hair feeling weighed down or greasy—this is one of those “depends on your hair” situations. The instructions suggest 2–4 pumps, but you’ll still have to find your personal sweet spot.
What to know before you buy
How it’s used
You apply 2–4 pumps to dry or damp hair, then distribute evenly from root to tip. After that, you leave it overnight. It’s intended for repeated use “as often as required”, depending on hair damage and fragility.
A micro example of use: imagine you’ve just had highlights done and, after washing, your hair feels a bit spiky and tangles easily. You towel-dry (or keep it slightly damp), pump out a small amount, smooth it through from mid-lengths to ends (and only as far towards the roots as you comfortably can), then braid loosely before bed if you’re prone to matting. In the morning, you’d expect detangling to be less of a battle.
Bedding stain concern
The base description specifically says it should leave no colouring or stains on bedding. That’s a key consideration for any overnight product, so it’s worth taking seriously when you decide whether it’s worth adding another step to your routine.
Tech summary
Tech specs
- Name: Blond Absolu Serum Cicanuit Conditioning Leave-In Hair Serum, Overnight Treatment
- Type: Overnight leave-in hair treatment for lightened or highlighted hair
- Format: Conditioning leave-in hair serum
- Size: 90ml
- Ingredients (stated): Hyaluronic Acid and edelweiss flower
Where it shines (and when it doesn’t)
It makes sense if you’re lightening or have highlighted blonde hair and you want an overnight conditioning step that targets hydration, fibre “plumping”, and friction-related breakage concerns. If you regularly wake up to tangles and want a softer, more detangled feel by morning, this is the kind of product that can fit neatly.
It’s not the best choice if you’re looking for something fast and daytime-only, or if you can’t commit to an overnight leave-in routine. Also, if your hair is very fine and gets weighed down easily, you may need to start at the lower end of the suggested amount and adjust from there.
You’ll likely get more value from this type of serum if you treat it as part of a damage-management routine (especially after bleach/highlights), rather than expecting it to replace proper care.
Is it worth it?
Worth considering if you want a leave-in overnight treatment made for lightened and highlighted blonde hair, with hyaluronic acid and an edelweiss flower focus, and you care about waking up with hair that feels softer and easier to detangle. The promise of no bedding stains is also a practical detail that makes the overnight format more usable.
However, you may want to skip it if you don’t like overnight products, if you wash early and won’t realistically leave it in, or if your hair is prone to feeling greasy or flat—then you’ll need to be extra cautious with how much you apply.
Quick FAQ
How often can you use it?
The description says you can use it as often as required, depending on the degree of hair damage and fragility.
Do you apply it to wet or dry hair?
You apply it to dry or damp hair, then leave it overnight.
Will it stain bedding?
The base information states it should leave no colouring or stains on bedding.
Does it help with detangling?
According to the description, it’s intended to leave hair soft and detangled when you wake up.
What should you check before choosing?
Check whether you’re comfortable with the overnight leave-in approach, and whether you’ll likely suit the 2–4 pumps application—especially if your hair is fine or easily weighed down.