KÉRASTASE Extentioniste Scalp & Hair Serum — 1.7 fl oz, lightweight leave-in to strengthen and prevent breakage

KÉRASTASE Resistance Extentioniste Scalp & Hair Serum is a concentrated leave-in treatment that soothes the scalp and fortifies hair fibers to help achieve stronger, longer lengths.

This lightweight, non-greasy serum targets both scalp comfort and hair reinforcement. Formulated with ceramides and active ingredients from the Resistance range, it repairs the internal structure of stressed or damaged hair, reduces the appearance of split ends, and helps protect strands from breakage while keeping the scalp balanced and comfortable.

How does this serum support longer, healthier hair?

The formula strengthens the hair fiber from root to tip, improving elasticity so strands resist snapping as they grow. Regular application focuses treatment where it matters most — at the scalp and immediate root zone — to reduce breakage that shortens length retention.

• Contains ceramides to rebuild internal hair structure and improve elasticity.
• Targets split ends and frayed surfaces to reduce breakage during styling.
• Lightweight, leave-in texture that won’t weigh hair down or leave residue.

How should I use the serum for best results?

Apply the serum directly to the scalp once or twice weekly using three pipettes per application. Work through sections, massage gently to distribute, and style as usual — no rinse needed.

• Use 3 pipettes for each treatment, once or twice a week depending on need.
• Divide hair into sections, apply to the scalp, then massage to activate ingredients.
• Follow with styling; compatible with Extentioniste shampoo and conditioner for a full regimen.

Will it grease my hair or interfere with styling?

The serum is formulated to be non-greasy and absorb quickly, so it won’t leave an oily film or affect your usual styling routine. It’s designed to sit at the scalp and hair root to deliver active ingredients without coating mid-lengths and ends excessively.

• Non-greasy texture suitable for all hair types, including fine hair.
• Leaves scalp feeling purified and comfortable without residue.
• Compatible with heat styling and daily products when used as directed.

What improvements can I realistically expect, and when?

You can expect improved scalp comfort, reduced breakage, and stronger-feeling hair over consistent use. Visible reduction in split ends and a smoother hair surface often appears after several applications, with longer-term strength gains over weeks.

• Short-term: soothed scalp and smoother hair surface after a few treatments.
• Medium-term: fewer breakages and improved elasticity with regular use.
• Best results when paired with other Resistance Extentioniste products for a complete routine.

Who is this for: This serum suits anyone aiming to grow and maintain healthy lengths—especially those with damaged, sensitized, or breakage-prone hair. It works across hair types and textures for users seeking a targeted, leave-in scalp and root treatment to strengthen strands, reduce split ends, and support long-term hair resilience.

Ingredients

Water, Polyquaternium-37, Paraffinum Liquidum / Mineral Oil, Amodimethicone, Polysorbate 2, Quaternium-7, Stearyl Alcohol, Menthoxypropanediol, Behentrimonium Chloride, Safflower Glucoside, Maltodextrin, Propylene Glycol, Candelilla Cera / Candelilla Wax, Ppg-1 Trideceth-6, Propanediol, Chlorhexidine Digluconate, Isopropyl Alcohol, Trideceth-6, Acrylates Copolymer, Sorbitan Oleate, Polyquaternium-11, Rose Extract, 2-Oleamido-1, 3-Octadecanediol, Cetrimonium Chloride, Camellia Sinensis Leaf Extract, Xanthan Gum, Tocopherol, Bht, Sodium Citrate, Fragrance.