Kérastase Genesis Serum Anti-Chute Fortifiant is a daily leave-in scalp serum for weakened hair that is prone to falling because of breakage. It is the leave-in step in the Genesis routine, used alongside shampoo and conditioner rather than in place of them.
The wording matters. Broken hairs and hair shedding from the root are not always the same problem. Genesis Serum is designed for hair-fall caused by breakage. If you are experiencing sudden shedding, bald patches, scalp pain or a change that concerns you, speak to your GP or a qualified trichologist rather than relying on a cosmetic product.
Shop Kérastase Genesis Serum Anti-Chute Fortifiant 90ml
What does Kérastase Genesis Serum do?
The serum is applied directly to the scalp and left in. Kérastase describes it as helping to reinforce and protect the scalp's natural barrier while helping prevent hair-fall caused by breakage.
Its formula includes diaminopyrimidine oxide, also known as Aminexil, plus ginger root extract, niacinamide, caffeine, resveratrol and arginine. The complete ingredients list is available on the product page and should always be checked if you know you are sensitive to a particular ingredient.
Genesis Serum is most relevant when the lengths feel weaker than usual, snap during brushing or styling, or have been stressed by colouring, heat or mechanical tension. It is not positioned as a medical treatment for underlying hair-loss conditions.
How to use Kérastase Genesis Serum
Use the serum once a day, either in the morning or before bed:
- Start with a dry or towel-dried scalp.
- Divide the hair into sections so the product reaches the scalp rather than sitting on the lengths.
- Apply three to four pipettes across the sections.
- Massage gently into the scalp.
- Leave it in. Do not rinse.
Kérastase recommends daily use for six weeks. Consistency matters more than applying extra product, so follow the recommended amount rather than soaking the scalp.
If the serum gets into your eyes, rinse immediately and thoroughly.
Should I use it on wet or dry hair?
You can apply Genesis Serum to a dry scalp or after washing, once the hair has been towel dried. Applying it section by section makes it easier to distribute the serum evenly at the roots.
The product is designed for the scalp, not as a finishing serum for the mid-lengths and ends. If your main concern is dryness or frizz through the lengths, choose a treatment or leave-in product intended for that job.
How often should I use it?
Use it once daily for six weeks. It can be applied in the morning or at night, whichever makes the routine easier to maintain.
There is no need to rinse it out before styling. If daily use feels heavy for your hair type, first check that you are applying it to the scalp in sections and staying within the recommended amount.
Can I use Genesis Serum with Genesis shampoo and conditioner?
Yes. The serum is the leave-in scalp step of the wider Kérastase Genesis range.
A simple routine is:
- Cleanse with the Genesis shampoo that best suits your hair.
- Condition the mid-lengths and ends.
- Towel dry.
- Apply Genesis Serum to the scalp in sections and leave it in.
The rest of the range includes options for different textures and levels of dryness, so there is no need to buy every product. Start with the cleanser, conditioner and leave-in steps that match your hair.
Is Genesis Serum for breakage or hair loss?
It is designed for weakened hair prone to falling due to breakage. Breakage happens along the hair fibre, often leaving shorter snapped strands. Shedding happens when a complete hair releases from the follicle.
It can be difficult to tell the difference at home, and both can happen together. Seek professional advice if the change is sudden, severe, patchy or accompanied by scalp symptoms. A cosmetic serum should not delay a proper assessment of possible medical, hormonal or nutritional causes.
How quickly will I see results?
Kérastase recommends a six-week daily routine. Hair response varies with its starting condition, the cause of breakage and the rest of the routine, so an exact result date cannot be promised.
Take a simple baseline before starting: note how much snapping you see during brushing, how the hair feels at the roots and whether styling causes visible breakage. Compare like with like after the full routine instead of judging the product after a few applications.
Is it suitable for coloured or heat-styled hair?
Genesis Serum is intended for weakened hair prone to breakage, which can include hair stressed by colouring or heat. It does not replace heat protection, careful detangling or a suitable conditioner.
Reduce unnecessary stress while using it: keep heated tools to the lowest effective temperature, avoid repeatedly tightening the same hairstyle, and detangle from the ends upwards.
Will Kérastase Genesis Serum make my hair greasy?
It is a leave-in scalp serum, so correct application is important. Use three to four pipettes in total, distribute it across sections and massage it into the scalp. Applying too much in one place is more likely to leave residue.
Fine hair may show excess product more quickly than thick hair. Start with careful sectioning rather than reducing the routine to a token amount that never reaches the scalp.
Which Kérastase products are right for my hair?
Genesis is one option within a much larger range. If breakage is not your main concern, another Kérastase family may be a better fit. Explore all Kérastase haircare or use the Kérastase hair quiz for a more focused shortlist.
The short version
Kérastase Genesis Serum is a once-daily, leave-in scalp serum for weakened hair prone to breakage. Apply three to four pipettes to a dry or towel-dried scalp, working section by section, and do not rinse. Use it consistently for the recommended six-week period, and distinguish breakage from sudden or unexplained shedding that needs professional advice.