I've been using this stuff from Garnier that seems similar to the salon version. You work a serum through your freshly washed, non-conditioned, towel-dried hair, and let it sit for 20 minutes. It smells like rotten eggs and is horrible like that, but then you wash it out, apply the styling balm, blow your hair dry and have lovely, straight, more manageable hair for 7 shampoos.
I cannot compare it to the salon version because my resolution last year was to stop going to salons and paying hundreds of dollars for chemical treatments.