L'Oréal Professionnel Keratin Alpha Sleek Professional Hair Mask 250ml

Transform frizzy, unruly or difficult-to-smooth hair with L'Oréal Professionnel Keratin Alpha Sleek Professional Hair Mask, a rich professional treatment created to deeply nourish while improving smoothness, softness, shine and control.

Formulated with Keratin-Alpha Shaper and Amino-Acid Chains, the mask works with the hair's existing keratin structure to help reshape and smooth the fiber. Hair feels softer and more hydrated, while unwanted frizz and excess volume become easier to control. L'Oréal Professionnel positions it for all hair types seeking smoother, more manageable results.

An important distinction: despite the name Keratin Alpha Sleek, the range does not contain animal-derived keratin. L'Oréal explains that the technology instead works at the hair's Keratin Alpha level, reshaping its existing keratin chains.

Nourish → Smooth → Control Frizz → Control Volume → Boost Shine

Why You'll Love It

• Deeply nourishes dry and frizz-prone hair
• Smooths the hair fiber
• Helps control frizz and unwanted volume
• Leaves hair softer and more manageable
• Provides immediate shine
• Helps create a sleeker, more polished finish
• Formulated with Keratin-Alpha Shaper + Amino-Acid Chains
• Rich, sensorial mask texture
• Suitable for all hair types
• Ideal between weekly Keratin Alpha Sleek smoothing treatments
• Artificial colorant-free
• Designed as part of the professional Keratin Alpha Sleek smoothing system

What Does Keratin Alpha Sleek Hair Mask Do?

This is the deep nourishment and maintenance mask within the Keratin Alpha Sleek routine.

It is designed for hair that needs moisture and conditioning but where the main styling problem is also frizz, unwanted volume and difficulty achieving a smooth finish.

The combination of Keratin-Alpha Shaper and Amino-Acid Chains helps smooth and reshape the hair fiber while the conditioning base — including Glycerin, Glycine and Shea Butter — helps soften and nourish.

L'Oréal's UK page reports that the Keratin Alpha Sleek system can deliver up to 5x smoother hair and 2x less frizz, but these figures relate to specified routine testing rather than the mask alone.

Who Is It For?

Ideal for:

• Frizzy hair
• Unruly or difficult-to-manage hair
• Hair with unwanted volume
• Dry hair needing nourishment and smoothness
• Thick or coarse hair that is difficult to control
• Wavy or curly hair when a smoother finish is desired
• Hair that becomes frizzy after drying
• Anyone wanting softer, shinier and more manageable hair

The range is officially described as suitable for all hair types.

Pair Me With

For the complete Keratin Alpha Sleek routine using products available in our Peggymou range:

1. L'Oréal Professionnel Keratin Alpha Sleek Sulfate-Free Shampoo 300ml
Cleanse first with the matching sulfate-free shampoo, formulated to prepare the hair for the smoothing routine.

2. L'Oréal Professionnel Keratin Alpha Sleek Professional Hair Mask 250ml
Use on normal wash days for deep nourishment, softness, smoothness and frizz control.

3. L'Oréal Professionnel Keratin Alpha Sleek Smooth Transformer 200ml
Use once a week instead of the mask when you want the range's more intensive, long-lasting smoothing treatment.

4. L'Oréal Professionnel Keratin Alpha Sleek Mirror Sleek Serum 50ml
Finish the routine before heat styling for additional smoothness, shine and heat protection up to 230°C.

Important: the Mask and Smooth Transformer are not intended to be layered together in the same wash. L'Oréal recommends the Smooth Transformer once weekly and the Mask on the other wash days.

My Hair Is Very Frizzy and Puffy – What Should I Use?

If your main problem is hair that becomes frizzy, puffy or excessively voluminous after washing, look for a treatment that combines nourishment with smoothing and fiber control.

Keratin Alpha Sleek Professional Hair Mask is specifically designed to hydrate and soften while controlling frizz and unwanted volume, rather than acting simply as a moisturizing mask.

It is particularly useful when your hair feels reasonably healthy but is difficult to keep sleek, controlled and polished.

What Is the Best Hair Mask for Smooth, Shiny Hair Without Frizz?

For smoother-looking hair, the mask needs to do more than add moisture. Conditioning agents that reduce roughness and improve the alignment and feel of the hair fiber can make a major difference to the finished result.

Keratin Alpha Sleek combines its Keratin-Alpha technology with a rich conditioning base and silicones, including Aminopropyl Dimethicone and Bis(C13-15 Alkoxy) PG-Amodimethicone, helping create a smoother, softer and more polished finish.

L'Oréal specifically identifies smoothness, softness, instant shine, frizz control and volume control among the mask's core benefits.

My Hair Gets Frizzy Again Soon After Styling – How Can I Keep It Smoother?

If smooth hair quickly becomes frizzy again, using the mask alone isn't the strongest option in this range.

Use Keratin Alpha Sleek Professional Hair Mask on your regular wash days, then replace it once weekly with Keratin Alpha Sleek Smooth Transformer.

For the complete long-lasting routine, L'Oréal recommends the Shampoo + weekly Smooth Transformer + Mirror Sleek Serum. The brand's two-week smoothness and frizz-control claim is based on repeated use of that complete system under specified testing conditions — not the mask alone.

Keratin Alpha Sleek professional hair mask | For all hair types

After washing with L'Oréal Professionnel Keratin Alpha Sleek Sulfate-Free Shampoo:

Apply the mask evenly through the lengths and ends.
Leave for 5 minutes.
Rinse thoroughly.
Continue with your styling routine.

For longer-lasting smoothing, use Smooth Transformer once weekly and use this mask on your other wash days.

Aqua / Water / Eau, Cetearyl Alcohol, Behentrimonium Chloride, Citric Acid, Cetyl Esters, Glycerin, Glycine, Isopropyl Alcohol, Aminopropyl Dimethicone, Potassium Hydroxide, Isododecane, Phenoxyethanol, Bis(C13-15 Alkoxy) PG-Amodimethicone, Butyrospermum Parkii Butter / Shea Butter, Steareth-100, Propylene Glycol, Hydroxypropyl Guar, PEG-150/Decyl Alcohol/SMDI Copolymer, Tetramethyl Acetyloctahydronaphthalenes, Polyquaternium-37, Linalyl Acetate, Propylene Glycol Dicaprylate/Dicaprate, Chlorhexidine Digluconate, Carvone, Citrus Limon Peel Oil, Limonene, Coumarin, Linalool, Citrus Aurantium Bergamia Peel Oil, Butylene Glycol, PPG-1 Trideceth-6, Pinene, Acrylates/Stearyl Methacrylate Copolymer, Sorbitan Oleate, Carbomer, Sodium Lactate, Taurine, Polysorbate 20, EDTA, Palmitoyl Tripeptide-1, Palmitoyl Tetrapeptide-7, Parfum / Fragrance.

L'Oréal notes that formulas can vary by market, so the ingredient list on the physical EU/Cyprus packaging should always be considered the final reference.