SHISEIDO Crystallizing Hair Straightener 400g Set: Step-by-Step

The SHISEIDO Crystallizing Hair Straightener + Neutralizer Cream 400g Set is a two-step rebonding system: Step 1 Hair Softener softens the hair, and Step 2 Neutralizer locks the straight shape in place. Three numbers decide the result – 10 to 20 minutes of room-temperature processing for Step 1 (up to 25 minutes for very coarse, thick hair), a flat iron at 180°C/356°F for 2-3 seconds per section, and 20 to 30 minutes for Step 2. Step 1 must never touch the scalp; keep it 1-2 cm away from the roots.

How do you apply Step 1 Hair Softener?

The short answer: apply it to the hair only, never the scalp, keeping 1-2 cm away from the roots and working evenly from the mid-lengths to the ends.

• Salon warning: if Step 1 touches the scalp, it can cause inflammation, blistering, or snap the hair root off completely.

How long does Step 1 stay on, and how do you know it is soft enough?

The short answer: 10 to 20 minutes at room temperature, extended to a maximum of 25 minutes for very coarse, thick hair – and the stretch test is what tells you it is done.

How to do the stretch test

• Take 2-3 strands of hair and pull gently.
• If the hair stretches like rubber to 1.5x its original length, the softener has processed enough.

Do you iron straight after rinsing?

The short answer: yes. Rinse with warm water until it is completely clean with no product residue, dry the hair 100%, then use a flat iron to set the shape.

• Flat iron temperature: 180°C/356°F.
• Iron one thin layer at a time and hold for only 2-3 seconds per section.

How do you use Step 2 Neutralizer?

The short answer: apply it evenly from roots to ends, comb it through, and leave it for 20 to 30 minutes – its job is to lock in the straight shape you just ironed.

• Use a wide-tooth comb to comb it straight and make sure the product reaches every part.
• Let the hair hang straight down and process for 20 to 30 minutes.
• Rinse thoroughly – leftover neutralizer can make the hair brittle later. Once rinsed, you can blow dry as usual.

Step 1 comes in 4 types – how do you choose by hair type?

The short answer: the range runs from strongest to gentlest as EX, H, N and S – the healthier, thicker and more resistant the hair, the stronger the type; the more damaged, the gentler.

• EX Straightener (strongest): for healthy, thick and very curly hair.
• H Straightener (strong): for healthy to slightly damaged hair.
• N Straightener (medium): for coloured hair or moderate damage.
• S Straightener (gentlest): for bleached or severely damaged hair.

What is the Neutralizer Cream n in Step 2?

The short answer: it is the shape-locking cream that gives the straight, heavy, moist and glossy finishing effect. The product page also describes this 400g set as the gentlest permanent rebonding system, aimed at very sensitised, bleached and severely damaged hair, with a long-lasting salon-quality straight finish and a heavy, moist gloss.

Why does bad timing ruin the hair?

The short answer: rebonding with a premium product like Shiseido needs skill and care, especially when reading the stretch test. Get the timing wrong and the hair can turn frizzy like wire, go “gummy”, or break off completely from being over-processed.

Summary

Follow the sequence – Step 1 kept 1-2 cm off the scalp for 10 to 20 minutes with a stretch test, ironed at 180°C/356°F for 2-3 seconds, then Step 2 for 20 to 30 minutes – and the SHISEIDO 400g set gives you a salon-grade straight finish. Before starting a DIY project, read our professional rebonding basics and technique guide, or WhatsApp our salon team to confirm your hair type; you can also view the SHISEIDO Crystallizing Hair Straightener + Neutralizer Cream 400g Set product page.