Grey hair is difficult to penetrate normally.
Holding the colour and hair growth in 2 weeks is a different thing.
What type of colour is the hairdresser using? permanent?semi? demi? grey coverage? 10 volume, 20 volume, 30 volume?
Is the colour you're doing it dark, light, etc?
Colouring every 2 weeks can have your hair with colour bands, for it's next to impossible to not do so on such little regrowth.
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