The main concern related to oxidative permanent colouring is the risk of irritation and allergic reactions. Hair dye residues ...

It depends on the type of henna - brown is safe, while black 'henna' is definitely not safe. Semi-permanent vegetable dyes such as henna are recommended by the NHS as a safe alternative if you do not ...

Semi-permanent dyes are more durable than temporary ... The natural hair colouring material henna is prepared from the henna plant, giving the hair a reddish-brown colour besides giving it a ...