I am trying to set ZSH as my default shell, however it keeps reverting back to bash.

I have tried this code:

sudo chsh -s $(which zsh)

I've also tried:

sudo chsh -s /bin/zsh 

Also tried these commands without sudo. Any ideas on what else I need to do. When running ZSH from within bash it loads up and works fine but I'd like to set it as the default shell.