L-Glutamine 500mg 90 Capsules. L-Glutamine is an important amino acid – a building block of protein. It is what we call ‘conditionally essential’ meaning it can be made by the body itself, but at certain times when the body is under ‘stress’, the body may be unable to make enough and supplemental glutamine may be advantageous.  Manufactured in the UK to GMP code of practice and supplied in innovative letterbox friendly and recyclable packaging.