—a plant famed for its dazzling whiteness and also called al-ʿarsaj. The Prophet ﷺ then said, “Change this grey hair, but avoid black.” This shows that the preferable course is for a person to dye grey hair, yet with any colour other than black—either with a yellowish dye such as henna, or with yellow mixed with katam (a plant that yields a black dye). When the yellow is blended with the black, the resulting shade is brown, so one may colour the hair brown or yellow, just as the Prophet ﷺ instructed.

Were it not for the trouble and expense such upkeep imposes on some people, everyone would do it; but maintaining the dye requires vigilance, for new hair emerges white while the ends remain coloured. His statement “but avoid black” proves that the black colour is prohibited, because it makes a person appear youthfully young once more, which runs counter to Allah’s natural order and His way in creation. All other dyes are permissible except black, for the Prophet ﷺ expressly forbade that colour. The only further restriction is when a particular dye is exclusively associated with the women of the unbelievers; in that case it is unlawful for believing women to use it, for doing so would constitute imitation of the disbelievers, and such imitation is forbidden. Allah is the One who grants success.