Overnight Youth Serum by Kérastase is a powerful age-corrective leave-in treatment designed to work while you sleep, reversing visible signs of hair aging by morning.

Infused with Pro-Xylane™ and Ochrophyta Algae, this advanced overnight serum delivers concentrated actives deep into the hair fiber to restore vitality, strength, and youthfulness—effortlessly, with just one pump.

Why you'll love it:

• As hair ages, it can lose density, shine, and smoothness. Overnight Youth Serum targets these concerns at their source, replenishing the hair fiber during the natural nighttime renewal cycle.
• Pro-Xylane™: A green-chemistry molecule renowned for its powerful anti-aging properties, helping to reinforce and densify the hair fiber
• Ochrophyta Algae: A rare, bio-sourced deep-sea algae known for its regenerative and revitalizing benefits
• Its ultra-light, quick-break texture melts instantly into the hair, leaving no residue—only soft, supple lengths infused with the iconic Chronologiste fragrance, transforming your nighttime routine into a luxurious ritual.

Who is it for:

Ideal for hair showing signs of aging, including:

• Loss of thickness

• Frizz and dryness

• Dullness

• Lack of volume and vitality

Perfect for anyone seeking visibly younger-looking hair by morning.

Visible results after just one night

• +5.7% thicker hair fiber*

• –66% frizz*

• +32% shine*

• +92% stronger hair*

• 77% say hair feels revitalized**

*Instrumental test after 1 use of Overnight Youth Serum
**Consumer test after one application of full Chronologiste routine (Bain + Masque + Overnight Serum)

Apply to dry or damp hair before bedtime.
Dispense one pump into your hands and distribute evenly through mid-lengths and ends.
Leave in overnight. No rinsing required.

Wake up to hair that feels fuller, smoother, stronger, and visibly healthier.

Aqua / Water / Eau, Dimethicone, Glycerin, Isopropyl Myristate, Phenoxyethanol, Polyacrylamide, C13-14 Isoalkane, Laureth-7, Benzyl Salicylate, Hexyl Cinnamal, Benzyl Alcohol, Linalool, Tetramethyl Acetyloctahydronaphthalenes, Carvone, Citrus Aurantium Peel Oil, Limonene, Pogostemon Cablin Oil, Citronellol, Linalyl Acetate, Geraniol, Hydroxycitronellal, Macrocystis Pyrifera Extract / Kelp Extract, Hydroxypropyl Tetrahydropyrantriol, Benzaldehyde, Geranyl Acetate, Coumarin, Citric Acid, Trimethylbenzenpropanol, Rose Ketones, Propylene Glycol, Beta-Caryophyllene, Potassium Sorbate, Sodium Benzoate, Parfum / Fragrance (F I L N70068793/1)