Conditionally essential amino acids are produced inside the body, but sometimes there is a shortage of them and it is necessary to complement them by synthetics. Conditionally essential amino acids include ie.: arginine and histidine. Arginine affects the nervous system, and its demand is increasing under substantial stress. Histidine is used during the growth and development stage and during diseases. Natural source of arginine and histidine are foods containing protein and protein supplements, anti-catabolic supplements, fat burners. Additionally, arginine (also available in the form of single-component supplements) is a component of NO-boosters and pre-workout products.
See also: histidine and arginine.