Does hair colouring actuli spoil ur hair?

i hav seen ppl havin colourd their hair nd i feel it actulli luks gud to see thm in tv , screens and all but sm of thm look so artificial...bt nwadays the hair dyes are soo natural and looks awesumnn ..is hair colourin relli harmful to hair ? i ve heard the dyes evn lead to cancer but look at ppl most of dem hav colord their hair nd their hair is soo healthy lookin and perfect! is it really harmful guys ? ppl who hav colourd thier hair plz share ur experinece..i lik my shiny black hair too bt i m curios to colour my hair..soo plz share ur experince guys!