Homocysteine is a natural amino acid made by the body during the metabolism of the essential amino acid methionine. The pathway between methionine and homocysteine is a cycle – methionine metabolizes to homocysteine, and then homocysteine recycles back to become methionine. During this cycle, nutrients are synthesized for biochemical reactions such as detoxification, healthy immune function, ideal joint and cartilage structure, and brain and cardiovascular health. The optimal functioning of this pathway depends on enzymes which require many important nutrients, especially B vitamins. Any roadblock during the process can cause an undesirable elevation in homocysteine levels. The amount of homocysteine in the blood is a great indicator of overall health, with the goal being to maintain a level within normal range, as determined by your health care practitioner.