How long can i leave L'Oreal highlights frosting on my brown hair?

You can typically leave L'Oreal highlights frosting on your brown hair for about 20 to 45 minutes, depending on the desired lightness and the specific product instructions. It's important to monitor the process closely to avoid over-processing, as hair texture and initial color can affect the timing. Always perform a strand test first to see how your hair reacts. For the best results, follow the instructions provided with the product.