Can I use this on bleached, highlighted, or very porous hair? — Toning shampoo light brown 40ml V21 victoria beauty

The formula uses direct dyes that don’t need peroxide, so it won’t further damage already-lightened hair. However, bleached or highly porous strands absorb pigment much more aggressively. In practice, the V21 medium brown can read significantly darker, almost dark brown, on bleached sections, and it may cling for well over 8 washes because the open cuticle traps the colour. Before committing to a full head, apply a small amount to a hidden strand, follow the recommended processing time, rinse, and evaluate. If the result is too intense, you can shorten the processing time on the next application or dilute the shampoo with a regular conditioner to soften the deposit. Also note that very porous hair may show uneven uptake if some areas are more damaged than others.