I don't really understand what you've been doing yourself and what has been done professionally. Have you consulted another stylist/ another salon or contacted L'Oreal? Maybe you have build up; have you tried a clarifying or chelating shampoo? Have you tried laying off the protein treatments, using oil-based treatments instead? Is your hair only dull when coloured or dull all the time? As far as I understand it shine is a sign of health, so maybe your hair is more damaged than you think?
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