Best keratin treatment for blonde hair: what to look for

For blonde hair, you choose a keratin treatment on two things: the smoothing chemistry and the dye in the formula. Bleached, highlighted and grey hair is more porous, so you look first at what actually smooths it. Some treatments smooth on plant tannin or on cysteamine; others use glyoxylic acid as a formaldehyde alternative. Then you check which dye is on the list. Below they are ordered by chemistry, so you choose the right one.

What to look for with blonde hair

Blonde that comes out of a bleach or highlights is more open in structure. Three points weigh the most.

The smoothing chemistry. For already-sensitised, bleached hair, the ingredient list is the first thing you check. A list with no formaldehyde, no formaldehyde releaser and no glyoxylic acid is the strictest choice; a glyoxylic-acid system is an alternative, but falls outside that strict definition.

The dye. Also check which dye is on the list: Blue Gold Premium Step 2 carries CI 44045, a blue dye; Bioplastia Vegan and Nanoplex Arginina carry CI 60730, a violet dye (listed as Acid Violet 43 on the Nanoplex list).

Rest and aftercare. We recommend giving freshly bleached hair time to settle before you smooth it, and following up at home with an aftercare for blonde hair.

The options, ordered by chemistry

Tannin or cysteamine

No glyoxylic acid on the list: these smooth on tannin or on cysteamine.

• Salvatore Blue Gold Premium 2x1000ml — Step 2 smooths on tannin: tannic acid is on its ingredient list, alongside CI 44045, a blue dye. For blonde hair, the Step 2 pack gives this tip: flat iron between 180 °C and 200 °C maximum, according to the strength of the hair fibre, to avoid dryness and tonality loss.
• Brazil Protein Bioplastia Vegan 1000ml — smoothing on cysteamine (cysteamine HCl on the list), with CI 60730, a violet dye. No formaldehyde and no formaldehyde-releasing preservative on the printed ingredient list; no animal-derived ingredients appear on the list.

Glyoxylic-acid smoothing (formaldehyde alternative)

Built on glyoxylic acid, a formaldehyde alternative — so outside the strict definition above.

• Vitta Gold Nanoplex Arginina 1000ml — a Nanoplastia cream on glyoxylic acid with Acid Violet 43 (CI 60730), a violet dye. A formaldehyde alternative.
• Cadiveu Brasil Cacau Eco Keratin Set — the Eco Keratin step smooths on glyoxylic acid.

Fresh from a bleach, and the aftercare at home

If your client is fresh from a bleach, we recommend settling the hair first with the Chemical Repair Duo 550ml before you smooth. For home, we recommend the Blond Hair Duo 550ml between appointments.

Who it is for — and who it is not

• For: blonde, highlighted or balayage hair that wants to be smooth
• Less needed for: dark or natural hair with no lightening — the dye in the formula matters less there and you choose on smoothing alone

In short

• For blonde, you choose by chemistry: tannin or cysteamine (no glyoxylic acid on the list) or a glyoxylic-acid alternative
• Also check the dye: blue CI 44045 (Blue Gold Step 2) or violet CI 60730 (Bioplastia Vegan, Nanoplex Arginina)
• No formaldehyde and no releaser on the printed list: Bioplastia Vegan 1000ml
• Glyoxylic-acid alternative: Vitta Gold Nanoplex Arginina and Cadiveu Eco Keratin