How long does the colour last and what affects how quickly it fades?

Because the pigments only coat the outer cuticle and are not oxidised into the cortex, the colour is temporary and washes out progressively. Most people see a visible tone for roughly 4 to 10 shampoos, but this varies widely. Highly porous or bleached hair holds pigment longer initially but may also release it unevenly as the cuticle swells and contracts. Frequent washing, especially with clarifying or sulphate-heavy shampoos, strips the deposit faster. Hot water opens the cuticle more than lukewarm, so cooler rinses help retention. Heat styling (blow-dryers, straighteners) and UV exposure also degrade direct dyes. To extend the refresh, use a gentle, colour-safe shampoo between applications, limit heat, and consider a UV-protective leave-in if you spend time in the sun. Re-application is safe whenever the tone fades — just repeat the strand test if your hair condition has changed (e.g., new highlights, chemical treatment). The product is not a substitute for permanent colour if you need full grey coverage or a lasting shade change.