From a personal perspective, it works wonders on dyed hair. Simply for greater protection, add 2 tablespoons of shampoo to each sachet along with the oxygenate. It does a better job, the difference is huge, and the hair remains silky.

Very good, on non-dyed hair it quickly opens up to cool blonde tones (eliminates the orange in the hair), and on dyed hair it does lighten but to a lesser extent. For a whole medium-length hair, it definitely requires 3 packets. It works fine with a 30-volume developer. The scent is indeed pleasant, however, it is obviously advisable not to inhale it.