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L'Oréal Professionnel Serie Expert Keratin Alpha Sleek Keratin serum for frizzy and unruly hair 50 ml
DescriptionHow to use itCompositions & ingredientsRelated productsCustomer reviewsGot a question?
Description
Enriched with 5% Keratin Sealer to seal the hair fibre
Controls frizz and volume for up to 10 washes
Protects against humidity (80%) and heat (up to 230°C)
Lightweight spray for easy, precise application
Ideal for unruly hair prone to frizz
Elevate your haircare routine with this professional finishing serum. Acting as a protective shield, this leave-in treatment coats each strand to deliver an instant "mirror-smooth" finish, while ensuring long-lasting manageability and supple control.
High concentration of Keratin Sealer
Enriched with 5% Keratin Sealer, this high-performance concentrate bonds keratin deep within the hair fibre. It effectively fills gaps and smooths the cuticle to tame volume and frizz, with proven results that last through up to 10 washes.
Thermal protection and humidity defence
An essential ally for blow-drying, this treatment provides heat protection up to 230°C and shields styles from environmental humidity (up to 80%). By encapsulating each strand, it glides effortlessly through hair for 3× faster styling, delivering silky-smooth results in record time.
REF:
3474637335618
How to use it
How to use L'Oréal Professionnel Keratin Alpha Sleek Serum?
Shake well before use. After your usual haircare routine, dispense 2 to 4 doses for fine hair (6 to 8 for thick hair) into your palms. Distribute evenly through mid-lengths and ends, without rinsing. For best results, blow-dry and then straighten with heated styling tools.
Tip: Apply to towel-dried hair for better absorption. Ideal for use after a disciplining hair mask.
Compositions & ingredients
The composition may be subject to variations, so we advise you to always check the list on the purchased product.
Ingredients may vary. For the most accurate information, please refer to the list on the product packaging.
Reviews
Rated 5 out of
5 by
CharlotteD from
Smooth and sleek[This review was collected as part of a promotion.] Ive recently used the L'Oréal Keratin Alpha Sleek Serum 50ml and I have to say I am really impressed with the results. From the first uses, I noticed a clear difference in the improvement of my hair, as it appears and feels much softer and sleeker.
Having afro hair, frizz has always been an issue for me, but after using this serum I have noticed a big difference especially in more humid weather.
My hair feels much more controlled throughout the day, but doesn't feel heavy or greasy and it's great that it lasts up to 10 weeks, however, I did reapply sooner to get the same effects. It also helps control volume perfectly, as my hair appears polished and styled, rather than puffy and frizzy.
Despite applying sooner, what I love most is the long lasting effects. With my hair care routine, I usually have to apply lots of products to try and reduce the frizz, however, with this product I have been able to use less products which means less chemicals on my hair, which can often make my hair feel cakey and greasy.
After numerous uses, I would definitely recommend the serum and I will definitely be repurchasing again. I have already recommended it to family and friends, especially my curly hair girls.
Date published: 2026-04-07
Rated 3 out of
5 by
LindsayF from
Use a small amount[This review was collected as part of a promotion.] I found this L’Oréal serum to leave my hair sticky and unmanageable. So after trying it and using a lot less it was slightly less sticky and kept my hair straight and manageable for longer than normal. I had shine and lot less frizz than usual .
Date published: 2026-03-27
Rated 4 out of
5 by
MeganJ from
Great product for taming frizz and getting that sl[This review was collected as part of a promotion.] Smooth, frizz free hair for up to 2 weeks with a lasting shine. Great for taming unruly hair and boosting manageability.
The spray aspect of the bottle is great as it’s mess free and the application couldn’t have been easier.
I have quite long hair at the moment and I used around 8-10 sprays. So this bottle will last quite a while
Date published: 2026-03-27
Rated 4 out of
5 by
NayhaaS from
Good but don’t like the smell[This review was collected as part of a promotion.] I like how it works and it does truly smooth my hair but I’m not a big fan of the smell. It smells really strong and similar to bleach. Other than that it is good. I like the packaging too.
Date published: 2026-03-26
Rated 5 out of
5 by
CathyS from
Five days straight smooth hair ❤️[This review was collected as part of a promotion.] L'Oréal professional keratin Alpha Sleek serum is a leave in serum for smooth, frizz free hair. Reprograms the hair for long lasting frizz control. Glass shine and easier styling in half the time. The serum seals the hairs keratin structure for up to 5 days straight smooth hair. Fights against 80% humidity and doubles up as a heat protectant too! The serum is heat activated with either a hair dryer or a straightener for long lasting results. Just divide the hair into sections, spray the serum into your hands and glide through sections until hair is coated before heat styling for best results. I used a straightener and I can definitely see a huge difference. My hair felt significantly smoother, easier to style and did last days before I needed a wash day! I love that the serum is colourant and alcohol free. Easier manageable glossy hair, an amazing serum ❤️
Date published: 2026-03-24
Rated 5 out of
5 by
IsabelliT from
perfect for a straight look with no frizz[This review was collected as part of a promotion.] great serum and works best with heat for a glossy look. Worth it’s value as a little goes a long way. Makes your hair smell light and salon-fresh.
Apply to damp hair, don’t rinse, and style with heat.
Date published: 2026-03-23
Rated 5 out of
5 by
LeahR from
Easy to use[This review was collected as part of a promotion.] Such an easy product to use, simply wash my hair and then spray onto it after. No harsh smells, good sized bottle, pretty purple colour so looks very nice. Heat activated so tends to work when using the hairdryer after washing.
Date published: 2026-03-09
Rated 5 out of
5 by
AlisonS from
Perfect hair care for a busy mum! So easy to use![This review was collected as part of a promotion.] I recently tried L'Oréal Professional Paris Keratin Alpha Sleek treatment and I'm honestly so impressed with the results. My hair feels incredibly shiny and smooth even after 3 days of using it. Usually my hair starts to lose that fresh Sleek look after a day but this has really lasted.
One thing I really love about it is there's no greasy heavy feeling my hair still feels light and clean. I'm just more polished. The product is super easy to use which is always a plus as I don't always have time for complicated hair routines as a busy mum. Another huge difference for me is the frizz control. It's great.
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