Are constant curls getting you down? After you’ve caught the Japanese hair straightening buzz, you’ll want to book the first flight to Tokyo (as soon as it’s safe to travel, and we’re allowed back into Japan).

What is Japanese hair straightening?

Japanese hair straightening (aka thermal reconditioning) is a permanent straightening solution for peeps who bemoan their natural curls. Here’s how it works:

  1. The stylist applies a solution to your hair that chemically changes its structure. Neat.
  2. They leave the solution on your locks for about 20 minutes, depending on hair type and length.
  3. Afterward, they wash it out.
  4. Your hair gets some conditioning treatment to make sure it stays straight.
  5. Your hairdresser passes straighteners through small sections of your hair at 356°F (180°C). (Again, the exact temperature may vary slightly depending on your hair type, or if your hair is damaged.)
  6. Once they flatten any kinks and curls, the stylist applies a neutralizer. In 10 minutes, this consolidates all the work your stylist and their Japanese straightening solution have done.
  7. You’ll then get a blow dry (without any styling brushes)

To make sure the look is complete, your stylist will often give you another once-over with the straighteners before you stroll out of the salon to show off your new, curl-free look.

How long does it take?

2 to 4 hours, but longer depending on hair length and type. Treatments can take 5 hours or more.

How long does it last?

Around 6 months — or as long as it takes to grow out.

How much does it cost?

$400 to $800+

Is it bad for my hair?

Not as bad as a lot of other chemical straightening treatments.

Was this helpful?

No need to jet set, though. You could visit your local salon or get a Japanese hair straightening kit. (But bear in mind that Japanese hair straightening is permanent until it’s grown out — so only go down the DIY route if know what you’re doing. Get it wrong, and it stays wrong.)

Here are the whats, whys, benefits, and risks of Japanese hair straightening.

person with japanese straightened hair headerShare on Pinterest
Ángela Rober/Stocksy United

In the U.S., Japanese hair straightening is gaining popularity. It had a brief period of popularity in the early ’00s, but it became less commonplace as keratin treatments began to take off.

Fast-forward to 2021 and, after years of growing dissatisfaction at the high risk and low reward of keratin alternatives, hair straightening Japan-style is regaining the top spot again — one formaldehyde-free treatment at a time.

Japanese hair straightening was, somewhat unsurprisingly, invented in Japan. Japanese folks had been rocking the chemically straight look for a whole 10 years prior to its emergence in the New York fashion scene.

What’s in the treatment?

There are a few key components needed for Japanese hair straightening.

A cystine solution

This is a chemical solution that’s applied to the hair for about 20 minutes. There are of course other ingredients, but cystine is the key player. It works by breaking the bonds between and in hair. This flattens out the waves, because science.

Cystine is some hardcore sh*t when it comes to hair products, and the structural changes it makes in your hair are permanent (until the treated hair grows out).

Conditioning treatment

After the cystine solution is washed out, your stylist will apply some conditioning treatment. As we said, Japanese hair straightening solutions are full-on. Deep conditioners will be necessary during the washing process after the application of the solution.

If the solution is in your hair for longer than it needs to be, it can cause damage. As with almost every chemical hair treatment, timing is essential.

Hair straighteners

If you’re in a salon, they’ll probably be ceramic-coated flat irons. These keep hair as straight as possible (as anyone who owns a pair will be eager to tell you).

After the conditioning treatment has been applied, small sections of your hair will be delicately straightened. A variety of combs and brushes and other hair tools will probably be called upon, too.


After the stylist uses hair straighteners (which may take several hours), they run a neutralizer through your locks.

Chemicals like the cystine solution can play havoc with your hair and scalp’s pH balance. Neutralizers bring them back to the levels you need to keep having pH-enomenal hair.

The neutralizer takes about 10 minutes to work its magic.

Was this helpful?

As with all things, there are pros and cons to Japanese hair straightening. They might also risk hair damage. If you’re unsure about the possible side effects of any hair treatment that uses chemicals, it’s a great idea to AMA your stylist.

Pros of Japanese hair straightening

  • It makes your hair straight. If you want straight hair, that’s a massive pro.
  • It’s permanent (at least until the hair grows out, usually about 6 months).
  • It doesn’t need restraightening until it grows out.

Cons of Japanese hair straightening

  • It’s irreversible. If you don’t like how your hair looks once it’s done, you’re going to have to wait about half a year to get your curls back.
  • There’s a risk of hair damage, especially if coloring or another chemical has also taken place. That’s just a lot of chemicals in one go.
  • It’s pricey. Like, hella pricey. Japanese hair straightening is a delicate and time-consuming procedure, and the costs reflect this. It’s not uncommon for the treatment to cost $600 to $800, and that’s not even at boutique or top-range salons. Sheesh.
Was this helpful?

Japan doesn’t have a monopoly on the hair straightening market. There are plenty of other options available if this method doesn’t feel like the right fit for you.

Here’s a brief rundown of how Japanese hair straightening compares to other common salon straightening treatments.

Japanese hair straightening vs. keratin straightening

Keratin hair straightening is a popular choice for people who want their waves gone. Keratin naturally occurs in nails and (importantly) hair. It’s a protein, and hair products from shampoos to pills use it for its healthy hair benefits.

A fair amount of debate circulates around keratin. There’s a lot of comparison between Japanese hair straightening and a keratin treatment called a “Brazilian blowout” or “Brazilian keratin treatment.”

There isn’t much cost difference between the two. Keratin straightening treatment takes much longer though. We’re talking about a 2-day treatment that takes 2 to 4 hours each day. That’s a real commitment. And for all that time, your hair will only remain straight for 3 weeks.

Another big difference is the use of formaldehyde-based cream in keratin straightening. This is a huge draw of Japanese hair straightening — there’s none of that here.

You may have heard of formaldehyde. It’s up there with uranium, asbestos, and lead paint on the list of stuff our Grandparents used to put in everything before they figured it can have pretty serious health consequences.

So while they have similar costs, thermal reconditioning is faster, lasts longer, and doesn’t require formaldehyde. Your move.

Japanese straightening vs. relaxer

There are many different varieties of hair relaxers. It’s a blanket term for lotions and creams that make curly hair easier to straighten.

Retailers sell a bunch of different chemical mixtures as relaxers. But most are alkali-based, with sodium or calcium hydroxide among the most common base ingredients. These are harsher on your hair than the cystine and ammonium thioglycolate solutions that play a role in Japanese straightening.

Relaxed hair may not be as healthy as hair that’s had the Japanese treatment. Relaxers strip an entire layer from the structure of your hair, where thermal reconditioning only breaks the bonds between layers. This is a pretty huge difference.

Relaxers are cheaper, certainly. However, their effects also only last for about 6–8 weeks. If you only want a short-term commitment to straight hair (like if you have a wedding or prom coming up), then having your curls relaxed may be your preferred choice.

For longer-term defrizzing though, Japanese straightening is the safer (albeit pricier) choice for you.

Japanese hair straightening is also known as thermal reconditioning. It’s gaining popularity in salons across the U.S. There are a few scare stories that suggest that it can be dangerous for hair. But, in truth, it’s no more dangerous than most other salon treatments.

The key ingredient is a straightening solution which contains a chemical formula whose active components are cystine and ammonium thioglycolate. Japanese straightening follows a similar process to other chemical treatments (rinsing, conditioner, neutralizer, etc.), but the stylist straightens your hair in small sections.

As far as costs go, it can set you back $400+, and that’s at the cheap end. The treatment takes 2 to 3 hours at least), but you won’t need to repeat it for around 6 months.