I went back to Japanese hair straightening because I’m leaving for a 3-week vacation that includes hot and humid Singapore. My normal hair in humidity tends to become frizzy and unmanageable. I function better and look more on-point when my hair is pin straight in this kind of environment.

I had Japanese hair straightening for several years when living in Hong Kong (everyone does it there), but am not sure what system it was.

What Is Japanese Hair Straightening?

Japanese hair straightening (thermal reconditioning) is permanent hair straightening.

This means that once you straighten your hair using this technique, it’s straight. Like permanent color treatments, Japanese hair straightening will grow out and then you’ll continue to touch up the roots.

I haven’t needed to use a hairdryer (unless I need to dry in a hurry) or flat iron since having Japanese hair straightening. It’s made my life much easier.

However, hair becomes nearly pin-straight which isn’t a look that everyone wants. If you want to just tame your curls or keep more body with straighter hair, you should consider Brazilian keratin treatments instead.

Brazilian Keratin Versus Japanese Hair Straightening

Brazilian keratin doesn’t gradually grow out like Japanese hair straightening. It will completely wear out over time so that the entire length of your hair reverts back to its normal state. This was frustrating to me, but keratin is MUCH better for your hair.

You can buy yourself a little more time with Japanese hair straightening because your permanently straight ends will weight down new growth and pull it flat.

On the left, is a photo of my Japanese hair straightening after washing it for the first time. On the right, is a photo of my Brazilian keratin (which I also loved) after washing it the first time. You can see the Brazilian keratin is a little wavier. I air dried both times.

Japanese Hair Straightening Methods

There are many different methods that you see around the US. Yuko is one of them. I have not read or heard great things about it. A few of the others have limited information online.

I wound up choosing iStraight, which is a method of thermal reconditioning that uses natural oils and is more conditioning. I have had my hair fried by an inferior system, so this was important to me, and my hair looked nice and shiny afterward.

iStraight comes in three different strengths so your stylist can mix them to match your hair if need be. If your hair is colored, you can also use this system. With some permanent hair straightening, you have to pick color or straightening as both would be too damaging.

However, I’ve since switched to a lovely Japanese salon called Montblanc Hair Field. The system they use is from Japan and I’m not sure what it’s called. It’s also fantastic and I pay less there than I did for iStraight.

Japanese Hair Straightening Care

When you can wash your hair after Japanese hair straightening depends on the type of treatment you get. With iStraight, I was told not to wash my hair for 72 hours. I survived this with no problem and my hair didn’t look too greasy. With the Japanese system, I can wash my hair 24 hours later though I usually wait at least 48 hours.

During the time that you aren’t washing your hair, you can’t exercise either unless you’re convinced you won’t sweat, which brings moisture to your roots. You can’t wear headbands, ponytails, put your hair behind your ear, sunglasses on your head, or do anything other than sleep that might crease your hair.

How to Maintain Japanese Hair Straightening  

I was told that I can use any shampoo that I like as long as it’s not drying. I read that the iStraight B3 Conditioner must be used to maintain your hair if you choose iStraight. My iStraight stylist didn’t seem to think any special shampoos or conditioners were necessary.

I’ve always used anything under the sun with no problems. I have also written about how to take care of a Brazilian Keratin treatment.

How Much Does Japanese Hair Straightening Cost?

The cost of Japanese hair straightening usually depends on the thickness and length of your hair. For iStraight, I paid $500 plus tip the first few times (but have pretty thick hair). Montblanc Hair Field charges $289–$549 depending on the system you’d like, thickness, and length of hair.

See also: Japanese Hair Straightening in San Diego

You need a consultation with a good stylist before you embark on Japanese hair straightening because it isn’t for everyone. Brazilian keratin might be a better choice for some.

My hair has behaved in line with the treatments I received in Hong Kong so I’m thrilled. I’m happy to answer any questions about it.

Katie Dillon is the managing editor of La Jolla Mom. She helps readers plan San Diego vacations through her hotel expertise (that stems from living in a Four Seasons hotel) and local connections. Readers have access to exclusive discounts on theme park tickets (like Disneyland and San Diego Zoo) and perks at luxury hotels worldwide through her. She also shares insider tips for visiting major cities worldwide, like Hong Kong, London, Paris, and Shanghai, that her family has either lived in or visits regularly (or both).

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  1. Pingback: Painless Laser Hair Removal at OasisMD | San Diego
  2. Hi!
    I just moved to HK and am looking for a good salon to have my hair straightened. I have had the Japanese thermal straightening done before and loved it! I had the Brazillian keratin treatment most recently but it is starting to wear off and I need to get my hair done before it does nuts with this humidity. I would love to know where you had yours done in HK and about how much you paid if you remember. Thanks!

    1. I had mine done at Private i in the Four Seasons Hotel. I can’t remember the name of the technician but he is great and my hair was always soft and shiney. I have had my hair FRIED at a cheaper salon in Central. I think Private i charges around $2500ish – I can’t really remember. I have A LOT of hair though and it’s below shoulder length. Mine takes longer than most. Call them to verify the price since that was also 2 years ago. Good luck!

  3. I was exploring your site, impressed with the health conscious vibe I picked up… until I saw this post. Please do some research and update your readers. My stylist (pregnant with twins) refused to offer this service once she learned about this:

    Within months that salon completely discontinued offering the service until further research could be done. Stick with the blowdryer or even better, learn to love your wavy, lovely hair.

    1. Yes, this is part of the reason why I went back to Japanese Hair Straightening (the subject of this post) which has been done for years and years in Asia. Of course, doing nothing to your hair is the best option, however, with mine it’s definitely a trade-off. Thanks for stopping by!

  4. I have rad that it is best to shampoo with a shampoo that does not have sodium chloride in it. As well, I have read that there is a Japanese product called Nano its a white milky looking spray that you are to spray on form time to time…do you know if anything about either of these two things?

  5. Hi, I’m really interested in the Japanese Hair Straightening and was wondering if this works for my type of hair (frizzy hair, similar to afro american type)…I saw a salon in Paris where they did say it also works for this type of hair…
    I have had my hair straightened with products but never with this kind of method so I was wondering if this would really work for me.
    If you have any feedback, I would be most grateful.

    1. Hey
      I just got this done earlier in the day and I am soooooo happy. My hair stylist was raving about how many girls with that type of hair come in. He usually caters to afro american and frizzy hair girls. I had a digital perm done in August and my hair was fried and dried and very damaged.. now my hair is absolutely beautiful. Just do you research before choosing a salon.. many places can over process your hair.

      1. Thanks Caroline, for your feedback…I’ll surely look into, I don’t there is anyone doing it here in Montreal, Canada…so I might check it out in Paris when I’m there…thanks again, cheers

  6. I’m curious about whether I should do keratin treatment and js every other time to give my hair a break? My hair feels so damaged but I dont want to stop straightening it. do you have any thoughts about this?

  7. How long Japanese Hair Straightening method keeps hair straight? Does this affect hair fall or any of kind of problem?

    1. I love it. Mine lasts about 4 months, but I can stretch it out to 6 if I’m busy and can’t find the time. My hair actually falls our less with the treatment because I brush it less and it gets less tangled. I also use less shampoo.

  8. My hair is mixed afro my dad from Barbados and my mother uk with fair straight hair. I definately have inherited more of the caribbean hair! I got fed up with the damage of old style Afro hair straighteners and have been having Japanese straightening for 6 years now. My hair is not great condition but is the best it has ever been. It is also the longest it has ever been. I have Brazilian blowouts from time to time in between to help the straightness last longer. I try not to have a japanese straighten more than every 9-10 months although have done it with as little as 7months in between. My hair stays v straight for 2-3 months I can wash and go. After that it takes blowdrying to make it look nice . After 4months I have to start tonging the roots. Around then I will have a Brazilian which makes it dead straight again and puts some condition in it. The problem with this tho is having to use sulphate free shampoo and I swim in salt water alot which washes it out. I hope this helps

    1. How does your hair looks right after you get out of salt water? I’m interested in asking you so many questions regarding caribbean hair and swimming since I want to start surfing and I don’t want my hair to be a bother. Please contact me at lizbethsanchez5@gmail.com

    2. Thanks, I wanted to try a Brazilian in between Japanese straightening, esp. since I need bang touch ups every 3 months.
      My hair also loses the silkiness around then as well. I also sometimes get a little over processed lately, which concerns me, thinking of trying something different than Yuko. Maybe Liscio or IHR? Doing some research.
      Good to know I can combine Brazil w/ Jap.

  9. Hi La Jolla mom!

    I also live in San Diego 🙂
    Id love to have japanese hair straightenin
    I tried the Brazilian one and it lasted maybe 2 months at most. I was wondering how much the touch ups cost you if you don’t mind me asking and does it look really funky if you let it go say 6-8 months (or if you decide to grow it out)? I can’t find any pics online. Just curious. Thanks!!!!

  10. Hi, I moved from New York to Miami. My hair is kinky-curly. I went to a salon in Little Havana and the salon owner suggested I have both the Yuko Japanese straightener AND a Keratin Treatment on top of it. I also had some over the counter color in my hair, but otherwise my hair was natural. I hesitated putting any relaxer in my hair because it took a few years just to grow it out of an overprocessed condition. However, the humidity in Miami in intense and my hair looked horrendous. My hair looked amazing the first year (I had the treatments three times in two years). However, eventually my hair just started shedding and breaking off. I lost length and thickness and now have new growth. I don’t know what I should do now because i have about three inches of natural new growth and the rest stick straight hair, and yes, it looks a mess. Does anyone know if applying both treatments simultaneously is harmful and may be the reason for the breakage and loss of hair? If I just decide to stick with the Keratin treatments moving forward, will my hair break at the point of the natural hair and where the Japanese straightener was applied? Anyone has any suggestions for getting my hair back to health? Thanks!

    1. Very interesting. I have written and experienced both treatments but never heard about anyone getting them simultaneously! I wonder if both weakened your hair? I wish I had suggestions for you. When I had my hair fried by an inexperienced technician, my salon applied a deep conditioner several times that helped make it look better.

      1. Hey lajollamom! I have been wanting to have either the Japanese or Keratin. Which one do you suggest I have done if I manly just want to get straight hair? After the 3 days with the keratin when you wash you hair will you hair stay straight without the use of a flat iron or will you hair go back to its naturally curly, frizzy state?

        1. I would probably suggest Japanese. Once your hair is straight, it’s straight and gets curly at the roots as it grows out. A Brazilian just falls out of your hair entirely.

  11. I perform the Bio Ionic (Retex) thermal reconditioning in San Francisco. What my clients love about it is that it permanently straightens the hair but does not sacrifice the body. On top of that, their hair can still be styled and curled. ( there are other types of thermal reconditioning that leave the hair pin straight but it cannot hold any sort of bend or curl. It’s nice to have a choice).
    Www.thermalreconditioningSF.com will tell you a little about both methods.

  12. I am new to San Diego and would love to find someone to straighten my hair using the iStraight system as I have had amazing results with this in the past. Do you have any suggestions for salons and stylists with experience? Would you still recommend the Posh Salon in La Jolla? Any advice is much appreciated. Thanks!

    1. I actually don’t know the answer to that in a technical sense. However, my hair breaks less and I lose less of it because it’s easier to comb and shampoo. I don’t notice it growing faster though!

  13. Hi,

    I am an expat living in Kunshan, China. My husband and I just moved here a week ago and I have always been interested in getting my hair permanently straitened. It is not naturally curly, it is just dull, thin, and a little frizzy. The humidity here doesn’t help…my hair is just a gross frizzy mess. I made an appointment at Hip Hair Culture in Shanghai. I just wanted to see if anyone has ever heard of this place. When I looked online it was ranked as one of the best in Shanghai but the guy I spoke with did not speak English that well. I guess I am nervous and looking to see what anyone’s thoughts are. I don’t want to do something impulsive and ruin my hair. It is on the thinner side…

    Any thoughts appreciated. Thank you.


    1. hey Chelsea, i got an appointment fot the same thing in hip hair culture.. for tomorrow.. i’m nearvous as well! did it turn out ok? (: (:
      thnak you!

  14. Hey I love this post comparing the two but I’m torn between the permanent japanese straightening or the keratin/brazilian. I’m half white, one quarter japanese, and one quarter chinese. I’ am worried the japanese straightening will be TOO harsh on my hair and fry it but I love the idea of my hair being permanently straight and I don’t want to spend a ton of money for a keratin treatment for it to wash out (I do however wash my hair every other day).
    My hair hair isn’t coarse, too frizzy or very thick it just has a slight wave to it other than that is on the straighter side. I do straighten my hair almost daily because I like the really naturally straight look. I can sometimes get away with straightening only the the lower two thirds so a permanent straightening wouldn’t look terrible growing out.

    What would you recommend?

  15. If you are going on holiday to Asia, then have it done there! It is way cheaper in Asia. I had one thermal reconditioning done in Singapore and it was about £90 british pounds with tips and free Joico shampoo & conditioner (so very roughly $140)! I used to pay £300-350 in London (about $500). It is even cheaper in Malaysia. If you go to Kuala Lumpur, you can get the Shisheido straightening in an actual Shisheido salon for £70 (about $110).
    I would love to know if it is good value in Japan too?

    I have had 7 Yuko treatments done over the years, 1 x tenso (L’Oreal) and one Shisheido.
    I would say that Yuko gave me the best results and my hair never felt fried up, it was always smooth. I would not recommend x tenso by L’Oreal. Shisheido was extremely decent but the strands that had been Yuko-ed and then Shisheido-ed were very dry after a few months. This never happened with Yuko. I have heard great things about Liscio (I noticed that they were popular in Italy) but have never had it.

    Some people have mentioned that Yuko gives very poker straight results, which is true, and this is why I love it! Yuko is now doing an anti-frizz straightening treatment that I believe would leave you some bounce.

    However, I style my hair a lot in a vintage 40s and 50s fashion and I think that my Yuko hair does keep the curls and styling very well. Sharp hair styles need a smooth base (and a lot of spray!).
    Hope this helps some decide what is best for them.

  16. Hi, thank you for the info. I really like my Karmin and I have super curly, frizzy hair. My hair stays straight til my next wash with few touch ups. 🙂

  17. As a stylist, I want you all to know about a completely new technology called #Olaplex. It does not fall into any category because it was not even been invented until mid 2014. What it does is to rebuild bonds in the internal structure of your hair. Bonds get broken every day but especially during chemical processes. Find someone who incorporates Olaplex into the thermal reconditioning service! An experienced straightening specialist and Olaplex are the best combination when getting your hair chemically straightened.If you hashtag #Olaplex, you will find it all over the internet. (it can also be used with keratin treatments although from a health stand point I personally don’t recommend keratin treatments.)

  18. Is the Japanese straighteners available in South Africa?
    I am looking for a good hair product to import to Botswana or South Africa

  19. How do you sleep the first few nights after its straightened? If it kinks while you’re sleeping what do you do?

    1. I’ve never had a problem with it and I toss and turn. I was told to use a flat iron the next morning if it does happen to kink or get a little wavy from sleep.

  20. I have been getting my hair Japanese straightened for 10 years now .it’s awesome for a whole year I never have to use a hot iron it makes it silky smooth and the humidity in the summer doesn’t bother it at all and I live in New York City .the best place to go is SEI. They were the first ones to use Japanese hair straightening. They are experts. Once I went to a salon for a cheaper version. Ruined my hair.never again….

  21. I responded a few years ago on this site. I was using a different product when I first responded ( I’m a Thermal Reconditioning specialist in San Francisco). Since then I’ve switched to Liscio. I LOVE Liscio. Although I still perform some Yuko and Bio Ionic Straightenings on clients, I do 95% of them with the Liscio method. The hair still retains some body and there are a lot of little extra steps which keep the hair super healthy and glossy. My website explains some of the different methods and what you can expect from each. I don’t want to be all spammy here so I hesitate to list the site but I will anyway because I think it’s informative and educational:). www.thermalreconditioningSF.com