Piur London Rebonding Keraplex (1000 ml) is a professional hair realignment treatment, the smoothing step of the Rebonding protocol, for dense, coarse or chemically resistant hair carrying volume and frizz. What sets it apart is the route and the heat: glyoxylic acid sits second on its ingredient list, the bottle carries the Formaldehyde Free seal, and its printed iron range reaches 230 °C. It processes for 40 minutes at room temperature, then the hair is rinsed, dried completely and ironed.

Why a glyoxylic smoothing treatment

Resistant hair holds its volume in the structure of the fibre. It works on that structure with glyoxylic acid, the entry straight after water on its list: it is spread evenly through the hair, left to process without heat, then rinsed out, and the flat iron sets the result pass by pass in fine sections. You stay in control at three points: how evenly the cream is spread and combed through, how completely the hair is dried before the iron, and where you set the iron inside the printed range for the hair's type and resistance.

Key ingredients

• Glyoxylic acid: second on the list, straight after water. The realignment active, and the reason the treatment is processed and then ironed.
• Cetearyl alcohol and isopropyl palmitate: fourth and fifth, the cream base that carries the active along the lengths.
• Polysilicone-29 and coconut oil: seventh and eighth, conditioning agents.
• Cetrimonium chloride and behentrimonium methosulfate: ninth and fourteenth, conditioning agents.
• Tamarind fruit extract, shea butter, macadamia, olive and argan oils: from seventeenth down, the botanical part of the list.
• Silanetriol and panthenol: 35th and 36th, near the end of the list.

What to expect

Volume and frizz come down and the lengths dry smoother, while the hair still moves. Regrowth comes through in the client's own texture, and how long the result holds depends on how often the hair is washed and what the client uses at home.

Who it is for

• Dense, coarse or resistant hair carrying volume and frizz the client wants brought down
• Natural or previously coloured hair that passes the strand test
• Salons that want a glyoxylic-acid smoothing service
• Professional use on adult clients

Who it is not for

• Bleached, highlighted or heavily lightened hair: as salon practice, that hair rarely tolerates the top of this iron range. Reactive Pro Smooth Therapy is made for it
• Hair that fails the strand or elasticity test, stretching when wet without recovering: rebuild it first
• Under-18s and home use: the bottle states professional use only, intended for adults

Professional tip

On hair that is borderline at the strand test, make the passes your dial, not the temperature: stay at the bottom of the printed range and work toward the top of the printed pass count rather than chasing heat.

How to use

Two ways to run it: the directions printed on the bottle, and the Brazilian salon method, which works with the same figures and adds the craft around them.

Method A: manufacturer method

1. Apply Keraplex evenly throughout the hair, keeping a distance of 1 to 2 cm from the scalp.
2. Leave on for 40 minutes at room temperature.
3. Rinse with water until the product is removed.
4. Dry 100% with a hair dryer.
5. Flat iron in fine sections at 160 °C to 230 °C, according to the hair type and resistance, 10 to 15 passes per section.

Method B: the Brazilian method

1. Strand test. Run the whole service on a hidden section before the full head: it tells you where in the printed iron range this hair sits. Salon practice, not a step printed on this bottle.
2. Prep wash, then dry. Wash with Rebonding Shampoo and dry the hair completely, so the treatment is not diluted by water left in the fibre.
3. Section fine. Quadrants first, then fine sub-sections. Apply with a tint brush, keeping the scalp distance in Method A.
4. Comb through. Fine-tooth comb, root side to tip, so every strand is coated and nothing drips. Excess left in the hair is what smokes at the iron.
5. Process. For the time in Method A, at room temperature: no cap, no dryer, no heat during the pause.
6. Rinse and check. Rinse thoroughly, then feel a strand. If it still feels coated, rinse again: residue left in means uneven smoothing and smoke at the iron.
7. Blow-dry smooth. Dry 100% with a paddle or round brush on medium heat. A smooth dry means fewer passes later.
8. Seal by hair condition. Stay inside the range in Method A. As general salon guidance, virgin, coarse or resistant hair goes toward the top of it; previously coloured, finer or porous hair toward the bottom, around 160 to 180 °C; hair that was borderline at the strand test stays at the bottom. Never above the printed maximum. Slow, even passes, root side to tip, within the printed pass count.
9. Gloves and air. Gloves for the stylist throughout, and extraction or an open window at the iron.
10. Aftercare. Leave the hair loose. Book the next colour service after this one, not right before it: an acid smoothing step and an iron can soften a fresh tone.

Where it fits in the Piur London range

Keraplex is the service itself, the step you charge for, and Rebonding Shampoo is the preparation wash that runs before it. For blonde, highlighted or sensitised hair, the same two-product logic exists as Reactive Pro Smooth Therapy, whose printed iron range stops lower, opened by Reactive Pro Shampoo. Both protocols sit in Piur London Professional.