I have a walmart brand natural supplement for metabolism support that just expired 06/2013. is it safe to take?

Probably: However, why would you want to take it in the first place? These supplements generally have no value and are a waste of money.

Probably: Expiration dates on both drugs and supplements tend to be rather arbitrary and most of these are probably still safe to take a year or longer past the expiration date. Over time they may lose some of their potency but it is unlikely taking them would do any harm. A supplement just a few months past expiration is likely perfectly fine.