They are both amino acids, and hence, taking them will not negate any effects.
It's like eating chicken and asking if beef will diminish the chicken's effects lol.
Now whether you actually need l-glutamine and l-arginine seperately as opposed to simply getting them from your diet, or protein powder is questionable. But, if you think it will help you then go for it, it's your decision.
__________________
You will die, when i say, you will die, back to the front.
Please tell me where to get steriods for the same price as L-Glutamine and L-arginine... Is this including the PCT's needed with the roids? and the pins, etc? I mean were talkin like 40.. Just PM me about gettin me some D-bol and sustanon 250, I mean at these prices I just cant pass it up.