Hyperhomocysteinemia is a medical condition characterized by an abnormally high level of homocysteine in the blood, conventionally described as above 15 µmol/L. Hyperhomocysteinemia is a medical condition characterized by an abnormally high level of homocysteine in the blood, conventionally described as above 15 µmol/L. As a consequence of the biochemical reactions in which homocysteine is involved, deficiencies ofvitamin B6, folic acid (vitamin B9), and vitamin B12 can lead to high homocysteine levels. Hyperhomocysteinemia is typically managed with vitamin B6, vitamin B9 and vitamin B12 supplementation. Hyperhomocysteinemia is a risk factor for cardiovascular disease; however, supplements of these vitamins do not improve cardiovascular disease outcomes.