L-ornithine is of central importance within the liver's metabolism for the removal of toxins from the body. The amino acid takes part in the formation of urea and so is required for the removal of excess ammonia from the liver. L-ornithine is very important for the build up of muscles and the break down of fats. It has therefore a major role in dieting and sport. It can prevent an increase in blood-ammonia levels and the fatigue associated with this when under strain L-Ornithine is also a factor in the release of important growth hormones. This is why it's popular as an anti-aging product: it can help to achieve a more youthful appearance. Anti-aging Vegetarians should ensure they have an adequate supply of l-ornithine, as to be effective a supply of it from meat is necessary. There only exist traces of this amino acid in plant-based foodstuffs.