hi there! is your hair in good condition? if not i recommend joico deep reconstructor as it helps to restore the hair (saved mine after some heavy dying to rescue a botched home dye)

to keep it nice when straightened i use loreal hotstraight which is a cream u put on wet hair that protects it from the heat and keeps it straighter once done. also lee strafford? /stratford? dehumidifier is excellent at creating a barrier and stopping humidity frizz. he also does an overnight thing you spray on and you wake up with less frizz and fly aways, but i do find my hair lasts a day less without washing when i use this. all his stuff is bright pink and available in boots etc

my hair is really dry and frizzy and i find a lot of stuff doesnt do what it says on the tin! but these thiings work for me. i also buy salon shampoo. its expensive but a 500ml bottle lasts me 6 months so not too bad.

diet wise eat eggs, nuts, seeds and oily fish as well as the usual fruit veg lean meat etc to help your hair