Permanent hair straightening ?

ok.. so i have curly hair but not to curly.. its like btw wavy hair n curly hair... so.. its like wierd.. n so i often straighten it. n its weak also.. from roots.. and has become more weak and rough.. no even shiny... just like dry gr.. so.. i was thinking like.. il start taking biotin pills... for lke 2 or 3 m,onths n once my hair gets stronger il get permanent straightening.. and continue my pills.. so that it'l not have too much damage coz of the veryy harsh chemicals they use.. wt u ppl thinhk of it???? like after geting permanent straightened ur hair will become rough stringy and weak more.. so.. is this a gud idea?? like i wannt my hair to be straight badly.. with no harm too..