Permanent
What is a hair dye patch test? 4-step tutorial to do it with ease
Is it really necessary to do a *hair dye patch test* every time you decide to change your hair colour? Yes, yes and yes again. It's easy to shrug it off if you're reinventing yourself as a redhead (for the umpteenth time), but this is one step in the colouring process not to skip, ever. Even if you've been colouring your hair for ages, it's still always possible to have an allergic reaction to hair dye – even if you've used that exact same hair dye before. Allergic reactions are rare, but they can be severe – the patch test helps indicate potential reactions ahead of time. Luckily, it's super quick and easy to do.