Quick answer: the Keratin Alpha Sleek Smooth Transformer, our price $61.88 (RRP $82.50), is a weekly at-home smoothing treatment, not a salon keratin straightening. After shampooing, apply it to clean, wet hair, leave it for 10 to 15 minutes, rinse, then use the Mirror Sleek Serum and blow-dry. Use it once a week for 4 weeks. L'Oréal says it gives up to 2 weeks of frizz control.
Updated 15 November 2026 by the stylists at Next International, a L'Oréal Professionnel salon in Oxenford and Upper Coomera on the Gold Coast since 1992.
What is Keratin Alpha Sleek?
It is L'Oréal Professionnel's anti-frizz range for hair that puffs up, takes forever to blow-dry or will not sit flat. It uses what L'Oréal calls a Keratin-alpha Shaper with amino-acid chains, which the brand says reshape the hair's own keratin to smooth it.
Despite the name, L'Oréal says the formula does not contain keratin. It works on the keratin already in your hair. It suits all hair types, including curly and wavy hair, and L'Oréal says it is safe on colour-treated hair.
Is it the same as a salon keratin treatment?
No, and it is worth knowing the difference before you buy.
| Keratin Alpha Sleek | Salon smoothing service | |
|---|---|---|
| Where | At home, in the shower | In the salon |
| Time | 10 to 15 minutes once a week | A few hours in the chair |
| How long it lasts | L'Oréal says up to 2 weeks per treatment | Usually months, depending on the service and your hair |
| Your curl | Smooths without permanently straightening | Depends on the service |
| Best for | Frizz and volume control you can top up | The longest-lasting smoothing |
One important point: L'Oréal does not recommend the Smooth Transformer on hair that has already had a straightening treatment, because it can leave the surface feeling dry. If you have had a salon smoothing service, use the Keratin Alpha Sleek Mask instead. Weighing up the salon options? Read nanoplasty vs keratin.
How do I use the Smooth Transformer?
- Wash with Keratin Alpha Sleek Shampoo and rinse.
- Squeeze out the excess water and divide your hair into two sections.
- Apply a palm-sized amount (L'Oréal suggests 30 to 50ml) evenly from the lengths to the ends. Keep it off your scalp.
- Leave it on for 10 to 15 minutes. L'Oréal says results peak at 15 minutes, so leaving it longer does not help.
- Rinse thoroughly.
- Apply the Mirror Sleek Serum to towel-dried hair.
- Blow-dry. For the sleekest finish, L'Oréal recommends following with a straightener at 210°C.
A heads-up from L'Oréal: the formula has a distinctive scent because of its actives. That is normal.
How often should I use it?
Once a week, or about every third wash, for 4 weeks. L'Oréal says performance peaks after 4 applications, so judge it at the end of the month, not after the first go. After that, keep using it weekly to hold the result. A 200ml bottle lasts about a month, around 4 to 6 treatments.
On your other wash days, use the shampoo and the Mask (5 minutes, then rinse), then the serum.
Which products should I buy?
The one that does the main work. L'Oréal says it gives up to 5x smoother hair, 2x less frizz and styling in half the time (brand tests). The 2-week result comes from a consumer test after 4 applications.
A gentle, sulphate-free shampoo that softens and adds shine. L'Oréal also says it is free from artificial colourants and alcohol.
Shop Keratin Alpha Sleek Shampoo, our price $52.80 (RRP $70.40)
A heat-activated serum with what L'Oréal calls 5% Keratin Sealer technology. It protects against heat up to 230°C and helps control frizz in humidity up to 80%. Use 2 to 3 pumps for fine to medium hair and 6 to 8 for thick hair, and shake it first.
A 5-minute mask for wash days between treatments. It smooths without weighing hair down, so curls and waves keep their movement. It is also the one to use if your hair has had a salon straightening service.
Shop Keratin Alpha Sleek Mask, our price $61.88 (RRP $82.50)
Shampoo and Smooth Transformer together come to $114.68. Add the serum and it is $174.91, and all four come to $236.79, which gets you free standard shipping.
Will it hold up in Gold Coast humidity?
On the Gold Coast, humidity is usually the real enemy. The Mirror Sleek Serum is the step aimed at humid days, and L'Oréal says it controls frizz in humidity up to 80%. The routine still needs heat to get the sleekest result, so if you air-dry, expect softer, less frizzy hair rather than poker straight.
Coloured as well as frizzy? Pair this with the right colour care from our Vitamino Color Spectrum guide. If your hair is breaking rather than frizzing, start with Absolut Repair Molecular.
Frequently asked questions
Is Keratin Alpha Sleek a keratin treatment?
No. It is an at-home weekly smoothing routine, not a salon keratin straightening. L'Oréal says the formula does not contain keratin and works on the keratin already in your hair.
How long do I leave the Smooth Transformer on?
Ten to 15 minutes on clean, wet hair, then rinse. L'Oréal says results peak at 15 minutes, so leaving it on longer does not help.
How often should I use the Smooth Transformer?
Once a week, or about every third wash, for 4 weeks, then weekly to maintain. On other wash days use the shampoo and mask.
Can I use Keratin Alpha Sleek on curly hair?
Yes. L'Oréal says it suits all hair types, including curly and wavy hair. It smooths and controls frizz without permanently straightening, so your curl comes back.
Can I use the Smooth Transformer after a salon keratin or straightening treatment?
L'Oréal does not recommend it, because it can leave the surface of the hair dry. Use the Keratin Alpha Sleek Mask instead.
Is Keratin Alpha Sleek safe on coloured hair?
Yes. L'Oréal says the Smooth Transformer is safe on colour-treated hair.
Need help choosing?
Next International is a L'Oréal Professionnel salon in Oxenford and Upper Coomera, and we sell the current Serie Expert ranges online at 25% off RRP.
Not sure if at-home smoothing or a salon service suits your hair better? Our stylists can talk you through both. Book online in Oxenford or book online in Upper Coomera, or shop the Keratin Alpha Sleek range. Standard shipping is free Australia-wide on orders over $200. Otherwise it is $14 standard (2 to 8 business days) or $18 express (1 to 5 business days), and click and collect from our Oxenford salon is free.
