Been taking Glutamine on and off for 10 years now. I'd use some and not bother again for a year or so. I can safely say that every single time I seem to take Glutamine, I grow, recover faster and my muscles feels harder. It's like anything really, right now, Glutamine is not the flavour of the month. Just wait a bit and an article will soon appear in Flex or Musclemag "Glutamine: What you may have been missing out on" or something similar. It happened to creatine, creatine loading, all was crap at one point, now it's cool again. People seem to pick sides very quickly because of an article they read or a big guy they spoke to in the gym. I have had people try to convince me in very eloquent language, supported by very selective research, that anabolic steroids are all placebo and don't really work.
I go by trial and error. Glutamine works great for me, it could do the same for you. Try it, don't let some nameless on the internet decide for you.