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Keratin Alpha Sleek Mirror Sleek Serum

Keratin Alpha Sleek Mirror Sleek Serum is rated 4.7 out of 5 by 46.
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1.69 oz.
#E4564700
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What It Is

A heat-activated leave-in serum that seals the hair's structure for up to 10 washes of smoothness, frizz control, and humidity protection.

What It Does

• Seals hair outer keratin structure for up to 10 washes*

• Anti-humidity up to 80% humidity in the air

• Heat protection up to 230C (450F)

• 6x smoother hair**

 

*leave-in serum vs. untreated hair

** system of shampoo, smooth transformer, and leave-on vs. before application

What Else You Need to Know

Formulated with 5% Keratin Sealer, this serum seals the hair structure for smoothness, frizz, and volume control that lasts up to 10 washes.

1. Shake well before use.

2. On washed, towel-dried hair, section hair into two parts.

3. Spray into your hand (start with 2–4 sprays for thin hair, 6–8 for thick hair) and distribute evenly from lengths to ends.

4. Do not rinse.

5. This product is heat-activated. Blow-dry completely.

6. For maximum long-lasting results, use a straightening iron after blow-drying.

DIMETHICONE • BIS-(MORPHOLINOMETHYL C1-4 DIALKOXYSILOXY) DIMETHICONE • BIS-CETEARYL AMODIMETHICONE • PARFUM / FRAGRANCE • LINALOOL • CITRONELLOL • GERANIOL

Purchases made in SalonCentric stores may be returned to any SalonCentric store. Purchases made through SalonCentric Customer Service, SalonCentric Business Partners, and SalonCentric.com orders Sold and Shipped by SalonCentric may be returned to a SalonCentric store; however, the return must not exceed $450 and must include the original receipt, packing slip, or invoice. For returns in-store of online orders, the refund will be credited back to the original payment method once the return has been processed. For SalonCentric.com Online Exclusive orders sold and shipped by third-party sellers, please see more details linked below for return steps.

The SalonCentric return policy does not currently apply to Kérastase & Shu Uemura purchases. Kérastase & Shu Uemura do not accept returns.

Click to see more details.

Rated 4 out of 5 by from Love I really like this product. I love and hate that it’s a spray bottle. I spray into my hand then apply to my hair. Otherwise it’s a bit too concentrated in one area. Adds glass like shine and I love that it has heat protection!
Date published: 2026-06-09
Rated 5 out of 5 by from Only use alongside full line You only wanna buy this if you’re getting the whole system. This isn’t really for retail, just professional as a mini Neese smoothing keratin blowout service. You must use all the products together like intended. And it’s a really good deal if you can get them on sale and it doesn’t add much time to your service.
Date published: 2026-06-09
Rated 3 out of 5 by from Smell is awful Doesn't weigh hair down however I did feel like I made hair look a little greasy. Helped with smoothing and humidity resistance. The whole line has an off smell to me,
Date published: 2026-06-09
Rated 5 out of 5 by from Lasts long After using it a few times I do notice a difference! It does help keep the shine and maintain frizz and curls. Has a thick consistency
Date published: 2026-06-09
Rated 4 out of 5 by from Wonderful This is wonderful for smoothing while styling. I wish the scent wasn’t as strong. It has a little different smell, would love to see that change
Date published: 2026-06-08
Rated 5 out of 5 by from Pleasant surprise I've been using this system for a few weeks now and I can honestly say my hair feels sleeker and more manageable. I live in a high humidity area and I can tell a difference in the smoothness of my hair after being outside. I also love the scent of these products!
Date published: 2026-06-08
Rated 5 out of 5 by from Sleek System! Amazing Sleek Serum to go with the Keratin alpha sleek anti- Frizz collection! Works well in conjunction with the rest of the system. Being someone who has frizz prone hair this is definitely a keeper! I did receive this product in exchange for my professional and honest review.
Date published: 2026-06-08
Rated 5 out of 5 by from Must have I love this serum! It’s a heat protectant and leaves hair feeling shiny and smooth. I noticed it still lasted through multiple shampoos. I love this whole line but this would still be a great addition with any regimen
Date published: 2026-06-08
Rated 5 out of 5 by from Favorite in the line This is probably my favorite out of this line. It smells like a perfume but not too much and reminds me of dream coat with adding shine and smoothness to the hair but I like the smell of this more and I feel lasts longer in my hair.
Date published: 2026-06-08
Rated 5 out of 5 by from Love the smell, and they way it leaves the hair feeling
Date published: 2026-06-08
Rated 5 out of 5 by from Frizz control I used this as a system. The shampoo is great nice lather decent smell. The conditioner is creamy yet lightweight and definitely leaves the hair smoother. The masque is heavier and ferls more like a deep conditioning service. The serum was probably my least favorite. It left my hair feeling slightly coated but still smooth. I have finer hair and thicker hair may not experience the same coated feeling. Overall its a great line and if uou live in a humid area it is great for frizz control
Date published: 2026-06-07
Rated 5 out of 5 by from Healthy smooth hair I absolutely love this hair serum. It is a heat protectant and also makes hair look super shiny. It feels like an oil. Hair looks and feels smooth and healthy after use. It also is heat activated.
Date published: 2026-06-02
Rated 4 out of 5 by from Nice Its a good treatment when used within the system its self to help keep clients hair smooth
Date published: 2026-06-01
Rated 5 out of 5 by from Heat activated serum Loved the results I got using this heat-activated leave-in serum.. it seals the hair's structure for up to 10 washes while helping with smoothness, frizz control, and humidity protection. It made my hair feel really nice and it gave it a shiny look as well.. not to mention it smelled nice!
Date published: 2026-06-01
Rated 5 out of 5 by from Great system! This system is amazing! The shampoo has a light lather, smells kind of musky, in a pleasant way. The masque is not heavy at all, so can be used even for fine hair. The treatment does exactly what it says by eliminating frizz but doesn’t weigh the hair down. I love that the serum is a spray, so it makes for an even application. This system is also great for curly hair in that it reinforces the curl structure while still taming the frizz.
Date published: 2026-05-30
Rated 5 out of 5 by from Amazing and light weight shine for all textures I received this product in exchange for a review. This serum is amazing!! You spray it into your hands then work into the hair. The moment you run it through the hair, it instantly tames and smooths any frizz. It add a lot of shine without looking greasy or oily. Leaves the hair feeling soft but doesn't weigh it down. This is my new fave product and go to for all hair types.
Date published: 2026-05-30
Rated 5 out of 5 by from Incredible finishing product for shine and softnes The product can be heavy so I recommend to follow the directions and spray on your palm, then distribute through the ends. Leaves the hair sooooo soft, shiny but not weighed down. So effective and smells wonderful!!
Date published: 2026-05-29
Rated 5 out of 5 by from Amazing! I love this whole system! It made my clients hair feel super sleek and removed the frizz. It makes great for a blowout style, and keeps your hair frizz free. It almost reminds me of a keratin treatment for smoothness. Definitely a must try!
Date published: 2026-05-29
Rated 5 out of 5 by from The Keratin Alpha Sleek Serum Honestly one of my favorite finishing products right now. It helps smooth frizz, adds shine, and makes the hair feel soft without looking greasy or weighed down. Perfect for that polished finish.
Date published: 2026-05-29
Rated 5 out of 5 by from 5 stars This leave in frizz treatment oil is beyond fantastic, it is a holy grail hair product for me. It is lightweight and leaves your hair feeling so amazingly soft and shiny and most importantly healthy. I have dry, damaged hair and with this oil my hair feels completely transformed when I use this! It leaves it shiny and soft that will last for days. All you need is a dime size amount, because a little goes a long way. I also love how it transforms my hair for the better. Where it usually would feel dry and dull, it definitely helps it being way less frizzy, even in the humid weather. All in all, this hands down is a perfect and reliable hair treatment that will not weigh hair down or leave a heavy residue. I love this stuff and I highly recommend it!
Date published: 2026-05-28
Rated 5 out of 5 by from needed for silk press clients! this made my blowout so silky and smooth! I paired it with the mask, and my client's dry, dull hair was transformed. I like that it is a spray vs a pump application, it does get greasy but the second you use heat, it melts into the hair beautifully. I would definitely try this if you do a lot of silk press services or just want a good add on treatment for blowouts. I received this product for free in exchange for my honest review.
Date published: 2026-05-28
Rated 5 out of 5 by from Finally something that really smoothes coarse hair The new L’Oréal Keratin Alpha Sleek Anti-Frizz System is my absolute favorite for my thick coarse hair! It makes my hair so smooth and actually silky for the first time in my life! Didn’t make my hair feel greasy or heavy and was able to withstand the humid weather we’ve had lately. I am really impressed. If you want glass hair, this is it!!
Date published: 2026-05-27
Rated 5 out of 5 by from Amazing product L’Oréal Professional Keratin Alpha Sleek Smooth Transformer is excellent for taming frizz and creating a smooth, polished finish. It helps control flyaways while leaving hair soft, silky, and manageable without feeling greasy. I noticed my hair looked shinier and stayed smoother for longer, even in humidity. A great styling product for achieving sleek, salon-like results at home.
Date published: 2026-05-27
Rated 4 out of 5 by from Would try again. This is my favorite product from this line. It smooths without weighing down. The smell isn't great but not as bad as the other products. Wouls use this again.
Date published: 2026-05-26
Rated 5 out of 5 by from Made my hair more sleek L’Oréal sent me this free sample through the Bzzagent sampling program in exchange for my honest review. This hair serum comes in spray bottle and offers heat protection of up to 450 degrees. It has an oily texture to it and made my hair feel softer and more sleek. It helped to tame down my frizzy hair and helped bring my hair back to life. It smells wonderful and the scent reminds me of roses.
Date published: 2026-05-26
Rated 5 out of 5 by from This is a powerful product
Date published: 2026-05-25
Rated 4 out of 5 by from Nice ! Great serum to help with keeping things tamed and in place. Has a pleasant smell and a good smoothing effect. Alittle goes a long ways .
Date published: 2026-05-25
Rated 5 out of 5 by from Smooth and sleek This serum really does work at keeping my hair frizz free without it looking greasy or heavy. I don’t love the way it smells when I first apply it, but the smell does not linger after I’ve done my heat styling. Will recommend to my clients!
Date published: 2026-05-25
Rated 5 out of 5 by from Fantastic I can not say enough about how much I love this sleek serum. The results are in the name “ sleek serum” ..Alittle goes a long way. My clients just love the results. Not greasy or heavy on the hair at all. Even my male clients love the results.
Date published: 2026-05-24
Rated 5 out of 5 by from Love this Great serum to help with keeping things tamed and in place. Has a pleasant smell and a good smoothing effect.
Date published: 2026-05-24
  • y_2026, m_6, d_19, h_13
  • bvseo_bulk, prod_bvrr, vn_bulk_3.0.46
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  • clientName_saloncentric
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  • reviews, product