Answer

Can we use hair dies / colours to colour the white hairs of our head / beard ?

wa ʿalaikum al-salām wa raḥmatullāhi wa barakātuh

It is permissible to dye white/grey hair with any color except black, for both men and women. That is the general rule in our madhhab, however, there is an exception: a married woman may dye her white/grey hairs black if her husband does not object to it.[1]

It is recommended to use ḥinna, however, one may use commercial dyes provided that they are free from animal ingredients, impure substances such as alcohol, and harmful chemicals.

Allah knows best.

[1]Baʿishn, Bushra-l-Karīm (p710, Dār al-Minhāj)

Answered by Shaykh Omar Mohsin