L'Oreal Professionnel Keratin Alpha Sleek Smoothing Hair serum is a professional leave‑in treatment that helps seal the keratin structure within the hair fiber for lasting smoothness, providing frizz and unwanted volume control for up to 10 washes.*

At the same time, it protects hair from humidity* and heat up to 230 °C*, making daily styling easier while leaving a subtle floral scent. The result is silky smooth, supple hair that remains under control longer, even in high-humidity conditions.

Keratin Alpha Sleek: Our first hybrid technology for hair texture and care. It acts on the alpha-keratin level of the cuticle for instant smoothness.

 
Why will you love it?

• Long-lasting smoothness – helps smooth hair for up to 10 washes*
• Frizz and unwanted volume control – for up to 10 washes*
• Helps seal keratin within the fiber for longer-lasting results*
• Humidity protection, even at 80% relative humidity*
• Heat protection up to 230 °C*
• Easier and faster daily styling
• For all hair types, with a delicate floral scent

 
How does it work?

• Keratin structure ealing: Helps stabilize keratin bonds within the fiber* so the hair surface remains smoothed and resistant to puffiness.
• Environmental control: Creates a protective film that shields against humidity*, reducing the appearance of frizz and unwanted volume for up to 10 washes*.
• Thermo-protective barrier: Helps protect the fiber from heat damage during styling up to 230 °C*, preserving smoothness and shine.
• Weightless care: The lightweight, non-sticky texture makes detangling and styling easier, leaving hair soft, supple, and fragrant.

 
How to use:
Apply a small amount evenly to clean, towel-dried hair from mid-lengths to ends. Do not rinse. Proceed with blow-drying or styling as desired (with or without heat tools). If needed, apply a small amount to dry hair for additional control and smoothing between washes. For optimal results, use as part of a complete care routine.

Warnings: Shake before use. Store in a cool, dry place. In case of contact with eyes, rinse them immediately and thoroughly with water. A change in scent over time is expected and does not affect the product's effectiveness.

 
*Instrumental test after 4 routine applications + 10 Sleek shampoos. *For long-lasting smoothness and up to 2 weeks of frizz control. ***Consumer test on 68 participants, 1 application per week for 4 weeks.

INGREDIENTS:

1261091 B2 - INGREDIENTS: DIMETHICONE • BIS-(MORPHOLINOMETHYL C1-4 DIALKOXYSILOXY) DIMETHICONE • BIS-CETEARYL AMODIMETHICONE • PARFUM / FRAGRANCE • LINALOOL • CITRONELLOL • GERANIOL (F.I.L. N70063363/1)