However, in mammalian non-hepatic tissues, the main use of the urea cycle is in arginine biosynthesis, so, as an intermediate in metabolic processes, ornithine is quite important.

The results suggested that L-ornithine has an antifatigue effect in increasing the efficiency of energy consumption and promoting the excretion of ammonia.

[6][7] Amino acid supplements, including L-ornithine, are frequently marketed to bodybuilders and weightlifters with claims for increasing levels of human growth hormone (HGH), muscle mass, and strength.

[8] A review from 2002 on the topic concluded "The use of specific amino acids to stimulate GH release by athletes is not recommended.

"[9] L-Ornithine L-aspartate (LOLA), a stable salt of ornithine and aspartic acid, has been used in the treatment of cirrhosis[10] and hepatic encephalopathy.