I hear some many people say they take L-glutamine on an empty stomach. I honestly, don't think it matters....IMHO.
Glutamine is an essential amino acid in the body and the most abundant in the body. Your body uses glutamine for several functions, especially during any type of stress. Taking a glutamine supplement will not only help you recover, increase GH release, but also strengthen your immune system, reduce infections and help digestion.
When you begin taking glutamine, don’t expect some huge change in your physique. You’re not going to grow over night or get super strong. However, you will find that with the proper dosage, based on your stress levels, that you will recovery faster and have less chance of getting sick. If you get injured, you should also up your daily dosage until you recovery.
A daily dose between 15-30grams where the most benefit will come into place. Take 5grams, 3-6 times per day. You can take it on an empty stomach, which may cause slight cell volumization. Glutamine can also be taken with a meal. This will help with digestion and absorption of the meal.