It’s more of a support supplement than anything really. It can help the gut and things like that. As for actual performance, alanyl-glutamine, or just glutamine with alanine, seems to be better able to make it to the muscles and perhaps help with endurance and things like that, but none of them are going to be really “muscle builders” to the same degree as, say, Creatine.
Yep. Assuming a quality extract, it’s great stuff.
you must include squats and deadlift in your workout regime If you want to gain muscles. Eat more calories especially on training days that include plenty of protein, carbs and vegetables and take adequate rest. If you need something additional to your diet for muscle gain, glutamine supplements are there to minimize the muscle breakdown and improve the protein metabolism.