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Formulated with a powerful 5% keratin sealing agent, L’Oreal Professionnel Keratin Alpha Sleek Mirror Sleek Smoothing Serum is the essential finishing touch for incomparably soft and manageable hair.

This professional serum is specially designed to enhance and protect the hair fiber. It works by microscopically sealing the hair’s keratin structure, creating an invisible shield essential for flawless styling.

This innovative process provides long-lasting softness, effective frizz control, and controlled volume for up to 10 washes*, for exceptional manageability and hold.

Discover the advanced protection and unparalleled comfort of this serum. Its formula actively protects against up to 80% humidity*, eliminating frizz, even in very humid conditions.

Furthermore, it offers excellent heat protection up to 230C*, essential for anyone who regularly uses hair dryers, straighteners, or curling irons, without damaging hair health.

Thanks to its unique action, this serum cuts your daily styling time in half**, saving you precious time for impeccable results. Used in conjunction with the complete Keratin Alpha Sleek routine, this serum transforms your hair for two weeks of smooth, frizz-free results with perfectly controlled volume**.

*Instrumental tests.

**Instrumental test after 4 applications of Keratin Alpha Sleek shampoo + smoothing treatment + serum.