What precautions should I take if my hair is bleached, highlighted, or chemically treated?

If your hair has been bleached, highlighted, permed, relaxed, or colored with a different brand recently, the cuticle is more open and porous. This means the permanent dye penetrates faster and can grab more pigment than intended, often resulting in a shade that looks darker, cooler, or more intense than the swatch. The source material specifically flags this: on very porous or heavily lightened hair, the final result may develop differently, so extra caution is recommended. Before applying to the whole head, do a strand test on a hidden section — use the exact mixing ratio and timing you plan for the full application. Check the result after drying; if it looks too dark or ashy, reduce the processing time by 5–10 minutes for the real application. You can also apply a light conditioner to the most porous ends (only the last 2–3 cm) before dyeing to slow pigment uptake slightly. Avoid overlapping dye on previously colored lengths when touching up roots; apply only to new growth and pull through for the last 5 minutes if a refresh is needed. If the hair feels gummy or stretches excessively when wet, it is too damaged for permanent color — wait and treat with protein/moisture masks first.