L-Arginine is a ‘conditionally essential Amino Acid’. This means that although the body can synthesise it from other amino acids, under certain circumstances, such as poor health, the Arginine needs of our body may exceed its ability to produce it and so it must be obtained from dietary sources, such as meat, fish, nuts and seeds. Supplementation has been shown to directly increase resting levels of Growth Hormone, and to reduce mental stress and anxiety to aid sleep.