From what I've learned, glutamine is burned up the most out of all the amino's when you're body needs energy. Therefore - it is essential for me since I play college football.. if I didn't take it, I would be burning muscle and potential muscle at a pretty high rate.
I know it is essential for me since I have an extreme rate of activity, but I"m not positive if you're just lifting.. We have to lift, run and practice.. all of which pretty damn intense.
I take in 20g's a day. I throw in 10g w each protein shake, mid morning and mid afternoon (after lift/run/practice).
My opinion..