L-ARGININE is an amino acid which is considered 'conditionally essential' because of the many important roles it plays in the body which may be compromised if a deficiency occurs. Of chief interest to athletes is its ability to increase muscle pump (and work capacity) by enhancing Nitric Oxide release.
Arginine's other claim to fame is its ability to stimulate the release of Growth Hormone from the pituitary gland, boosting recovery, fat loss, and potentially, muscle growth.
L-Arginine is commonly used by athletes to boost Nitric Oxide release for dilation of blood vessels and capillaries, providing increased blood flow to the muscles (leading to increased work capacity and muscle 'pump'). - for this effect use 2 to 6g before your workout.
L-Arginine is also commonly used to stimulate Growth Hormone release. - for this effect use 6 to 9g before bed.