Whey protein expiration?

Does "Whey Protein Concentrate 80% (Instantised)" go off?

In a nutshell, I do some exercise, I'm a vegetarian and I occasionally take some whey protein as a recovery drink, as sometimes I might worry I don't get enough high quality protein elsewhere.

I bought a tub of whey protein about 2 years ago; because I only use it occasionally, there's still some left.

There is no expiry on the tub - so my question is, does it go off? Should I throw it out and replace it? Smells and tastes fine.

I've googled this, but get a raft of contradictory information - anyone here know for sure?

Also, if it does go off, what's the risk? Could it make you very sick?