What is the real difference between permanent vs Semi-permanent hair colouring?
Both are not perfect 兩類都不完美
Permanent colour certainly affects the hair structure the most! In order to make the colour more “permanent”, it need to force open the cuticle and push the dye and other chemicals into the hair shaft. This option is most damaging but the colour lasts longest.
Semi-permanent used less harsh on hair than permanent. It will still open the hair cuticle to insert the colourant, but to a lesser extent. Though the colour will not last as long as permanent colouring。This option cause less damage to your hair.
Lastly is temporary colouring. Needless to say, this one is just depositing colours on top of the hair shaft. It would not cause structural change to the hair and is also the safest option. But it only lasts for a short time and likely easily washed away.
What is your choice?