One reason you may observe no difference after using Pink Platinum is if the hair is coated with polymers and silicone and requires clarifying. Barriers on the hair’s surface will prevent any Colour Restore shade from entering and evoking a change. To ensure those colour molecules can enter through the hair shaft and evoke change, always use either Precolour Clarifier or a clear clarifying shampoo prior to application. Clarifying the hair prior to application of any Colour Restore shade, will remove barriers and allow the colour pigments unrestricted access into the hair.
Another reason you may not observe any difference is if the hair was too dark prior to application. Colour Restore Pink Platinum is designed for use on lightest blonde hair. If used on any bases darker than light blonde, results from the product will be far more subtle.