Difference between Glutamine and L-Glutamine?

I was also thinking of starting to supplement with glutamine. But i see there is also L-glutamine. Could anyone tell me the difference between them and which one yields better results?

Glutamine v. L-Glutamine

Glutamine, like many other molecules, can exist in two forms which are not identical but are mirror images of each other, like the left hand and the right hand. Living things are full of such molecules but in almost every case, just about exclusively either the left-handed form or the right, and for other molecules--say, left-glove shaped molecules--to interact with them, you need, in this case, left-hand shaped molecules. In theory, glutamine could mean a 50:50 mixture of left-handed (L = levo = left) and right-handed (D = dextro = right), or any other ratio, of which only the L-glutamine would be of any use to your body. In practice, given the way glutamine is manufactured, you can assume that whether it's labeled L-glutamine or just glutamine, it's 100% L-glutamine. So don't worry if you see the L there or not.

amino acid v. L-amino acid

The same facts hold true for 19 of the 20 common amino acids in proteins. The one exception is glycine, where the shape of the molecule is such that there are not different mirror-image forms--that is to say, hold a model of the glycine molecule up to a mirror and what you'll see in the mirror looks exactly the same as the model you're holding up, whereas you hold your left hand up to a mirror and what you'll see in the mirror looks like your right hand.

Like glutamine, the other handed amino acids are in practice manufactured so that they're all L-amino acids. So don't worry if you see (for example, the branched-chain amino acids) leucine, isoleucine, and valine--you can assume it's all L-leucine, L-isoleucine, and L-valine.