Assalamu Alaikum Warahmatullahi Wabarakatuh

I am reliably informed that there are hair dyes which contain ingredients preventing the water from reaching the hair roots i.e. effecting its permeability. In short if there is anything that *prevents* water from reaching the hair or the roots of the hair then Ghusl is not complete and one would not be in a state of purity.

Which Brands are Halaal?
That is an extensive and engaging assignment. To petition relevant data from cosmetic companies is difficult enough. If you relay the ingredients, then I can forward a ruling based on this Insha-Allah Ta'ala.

We advise customers to telephone the Customer Services number displayed on the packaging and demand this information from the Customer Services Representatives. Say that you want them to check up with the QA department and then relay this information to us at [email protected]

Wa Alaykumussalaam Wa Rahmatullahi Wa Barakatuh