This Olaplex No.4P Blonde Enhancer Toning Shampoo is expertly formulated to neutralise unwanted yellow tones and brassiness, specifically targeting blonde, lightened, and grey hair whilst simultaneously strengthening and softening each strand. Featuring a highly concentrated, sulfate-free formula with patented Olaplex technology, it works to repair fragile bonds and deliver visibly brighter hair, achieving up to three times more luminosity compared to other purple shampoos. Integrate this gentle shampoo into your regular hair care routine for customisable toning; simply adjust the leave-on time to achieve your desired level of enhanced brightness and optimal results