Sensitivity test: is it necessary for every hair colouring application?
Yes, it is necessary to carry out a sensitivity test every time you wish to apply hair colouring.
Your sensitivity evolves over time, meaning you gain or loose sensitivity.
We recommend carrying out a skin test before every application of a hair colouring treatment, 48 hours prior.
Simply apply a small quantity of product behind an ear or on a wrist and wait.
If your skin reacts to this skin test, consult a dermatologist.