Sarah K La Vie en Rose Brazilian Vegan Protein (1000ml) is a salon smoothing formula built on wheat amino acids and free amino acids, with almond and myrrh oils. You apply it after the line's clarifying shampoo, leave it 45 minutes, rinse, dry the hair completely and set it with the flat iron. The front of the bottle carries a round 0% formaldehyde-free seal.

What makes this formula different

The working part of this formula is a run of amino acids. Wheat amino acids lead, followed by arginine, aspartic acid, glycine, alanine, serine, valine, isoleucine, proline, threonine, histidine and phenylalanine. Behentrimonium chloride conditions, and three silicones (cyclopentasiloxane, cyclomethicone, dimethiconol) give slip and shine under the iron. The heat of the plates is what sets the result. We'd place it at the gentle end of salon smoothing, for salons that want an amino-acid service on the menu next to their stronger systems.

What to expect

Expect hair that dries smoother, with less frizz and more shine, while it still moves. It softens the wave rather than flattening it, and it is not a relaxer. Sarah K prints no longevity figure on the pack, so we do not quote one; how long it holds depends on the hair, the ironing and the aftercare. What we see in practice is that fine sections and hair taken fully dry before ironing make the biggest difference.

Who it is for

• Salons that want an amino-acid smoothing service on the menu
• Frizzy, wavy or unruly hair that needs softening rather than a poker-straight finish
• Clients who ask for a formaldehyde-free smoothing with no keratin in the formula

Who it is not for

• Home use: the pack is marked for professional use and needs a flat iron and trained hands
• Anyone expecting a permanent straightening or a relaxer result
• Clients sensitive to methylisothiazolinone or the listed fragrance allergens

Professional tip

The mistake we see most is ironing hair that is still damp near the scalp. Take every section of your client's hair fully dry first, because the bottle says dry to 100 percent and means it. Keep the sections very thin, as the directions ask. Set your iron from the strand test, since the pack gives no temperature, and you will find the right heat faster. On very light blonde, run that strand test with extra care, because a violet colourant is part of the formula. Our rule is simple: if the test strand looks wrong, you stop there.

How to use

Run the service in one fixed order, from the clarifying wash through to the iron. Scan the QR code on the bottle first; Sarah K links the patch test and strand test information there, and both belong before the first application.

Each step prepares the next. Residue left on the hair keeps the amino acids from spreading evenly, and water left in a section stops the iron from setting it.

1. Clarify. Wash with the La Vie en Rose clarifying shampoo as many times as the hair needs. Leave it on for 3 minutes on the last wash, then rinse until no residue stays behind.
2. Apply. Work the product through strand by strand over the whole head. Leave a gap of 1 cm at the root, because the directions say not to apply it directly to the root.
3. Process. Leave it on for 45 minutes, which is the time printed on the bottle.
4. Rinse and dry. Rinse thoroughly, then dry the hair to 100 percent before any iron touches it.
5. Iron. Pass the flat iron over very thin strands, working section by section so the heat reaches every part of the hair.

Where it fits in the range

Buy it on its own when the back bar already holds the clarifier, or take the 2x1000ml kit with both litres together. To try the system first, the 3x100ml kit adds the line's neutralizer in a small size.

In short

• Amino-acid smoothing with almond and myrrh oils, 1000ml
• 0% formaldehyde-free seal on the front of the bottle
• 45 minutes, 1 cm from the root, fully dry, thin sections under the iron
• No temperature or longevity figure on the pack, so the strand test decides

New to formaldehyde-free services? Our formaldehyde-free keratin treatment guide explains what the label claim does and does not cover. Deciding between routes? The hair botox, keratin or protein comparison sets them side by side.