What kind of post-workout supplement should I take after a HIIT session? High glycemic carbs with Whey? Any other suggestions?

You can take supplements if you want but id prefer a nice carb meal like pasta to restore all that burnt off glycogen..

Theres not much that you need to have post HIIT really anway. If its hot and youve been sweaty a powerade or something similar will keep you isotonic. Maybe a pit of protein if you want. But defentitely carbs - if you can high Gi immedietly and low gi - more complex carbs after..