I have used the Japanese hair straightening method for the last two and a half years. I have it straightened about every six months. I have had no unusual hair loss, indeed, my hair is still thick.
My hair looks better and healthier than when it was curly. Some of my hair was wavy, but most of it was either curly or very curly. It often frizzed up during the day and became sort of bushy looking. While I am fairly talented at applying makeup, I am a klutz when it comes to working with my hair. I am not good at it, it look a long time, at least 20 min., and I rarely even tried to do it. Before I went out to a "special" event, I'd go have my hair washed and blown dry. I never got it to look that good.
Now, I get out of the shower with straight hair. I do not have to straighten it with an iron or anything else. I can blow dry it and it is still straight without any special processes or precautions. The only difference I have noticed is that my hair drinks up conditioner, but it did when it was curly too.
My hairdresser took a special class in learning this technique and he is very meticulous. I think this is mostly the reason for my success here. He applies more to the curlier parts of my hair than the wavier parts and the process takes between three to four hours. I have seen women who's hair has been straightened using this method, and I can see where the curlier parts were not treated longer than the less curly parts. Or, it looks like the whole process wasn't allowed enough time. But even my hairdresser has said that my hair just did better than others he has done.
So, the secret, if I have one, is to find a hairdresser who is trained and careful about this process.
It is worth it. It sounds like a bit of an exaggeration, but it has changed my appearance dramatically for the better. My hair shiny, medium length and attractive with no extra work or worry.