Is It L-Glutamine or Glutamine?

You may be wondering why the terms ‘glutamine‘ and ‘l-glutamine‘ seem to be used almost interchangeably. The ingredient labels for l-glutamine powders or capsules can be confusing. Is there a difference between glutamine and  l-glutamine — and does it matter?

My research left me a bit perplexed also, but it seems that ‘glutamine’ refers to the whole food form of the amino acid– that is, the glutamine component that would be found in a food, such as peanuts. (And according to wikipedia, the ‘biologically active form’ is glutamine.

L-glutamine, then, is the free form amino acid that we see in supplement form ( powdered free form amino acids are the most biologically available.  Hopefully that helps to clear things up.

In conclusion, you eat glutamine, as a natural component of foods, such as milk, yogurt, cottage cheese and fish. If you supplement your intake of glutamine, you will consume an l-glutamine supplement, which is the free form, and not the ‘whole food’ form.

Interesting fact about amino acids (from

“With the exception of taurine, GABA and glycine, most amino acids exist in either the D or L form. These forms are the mirror reverse images of each other. The L form represents the natural type found in living plants and animal tissues…”