How long is Glutamine powder good for?

[surfratt]

I have an older bottle of l-glutamine powder (a couple years) and the bottle does not have an expiration date. I am wondering if it is still good. I have stored it in a cool, dry, dark place. Thanx, surfratt

 

[The Terminator]

I put some out yesterday and it had a 2 year shelf life.