Glutamine and L-Glutamine are one and the same. You should take it on an empty stomach, first thing in the a.m. and just before bed. I assume you've bought the powder? Just mix it with a small amount of water (just a quarter of a glass, at the most) and drink it down.You cannot harm yourself with it -- in fact, it is one of the amino acids that produces others that we lose as we age (like glutathione, a very important anti-aging nutrient). It works by healing the lining of the intestines and, if you have IBS-D you will notice a significant improvement (at the above dosage) in less than a week.I buy pure Glutamine ( no flavors or fructose) from Jarrow and highly recommend it.