Homocysteine is an amino acid. Vitamins B12, B6 and folate break down homocysteine to create other chemicals your body needs. High homocysteine levels may mean you have a vitamin deficiency. Without treatment, elevated homocysteine increases your risks for dementia, heart disease and stroke.
Homocysteine is an amino acid. Amino acids are chemicals in your blood that help create proteins. Vitamin B12, vitamin B6 and vitamin B9 (folate) break down homocysteine to generate other chemicals your body needs.
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When it interacts with the B vitamins, homocysteine converts to two substances:
In a healthy person, homocysteine levels are around five to 15 micromoles per liter (mcmol/L). Nearly all that homocysteine converts to other proteins.
If you have more than 50 mcmol/L, the excess homocysteine may damage the lining of your arteries (blood vessels that carry oxygen-rich blood throughout your body). High levels of homocysteine can also lead to blood clots or blood vessel blockages. Artery damage or blood clots significantly raise your risk of heart attack.
Common Conditions & Disorders
Typically, homocysteine breaks down into other substances, and only small amounts of homocysteine remain in your blood. Some conditions interfere with this process and leave you with high homocysteine levels.
You may have too much homocysteine in your blood if you have:
Without treatment, elevated homocysteine levels can lead to severe health complications. Too much homocysteine increases your risk for:
You may need a homocysteine test if you have a high risk of heart disease. You may also need a homocysteine blood test if you have symptoms of a vitamin B deficiency. Common symptoms of vitamin B deficiencies include:
Unusual homocysteine levels do not necessarily mean you have a medical condition. Other factors can affect your homocysteine blood levels, including:
If you have high homocysteine levels, your healthcare provider may recommend taking supplements of:
Increasing your vitamin intake alone does not reduce your risk of heart disease. You can lower your risk of heart disease by:
You may want to ask your healthcare provider:
A note from Cleveland Clinic
Homocysteine is an amino acid. Vitamins B12, B6 and folate interact with homocysteine and create other proteins that your body needs. Typically, very little homocysteine stays in your blood. High homocysteine levels could mean you have an underlying condition such as heart disease or homocystinuria. Your healthcare provider may order a homocysteine blood test. Based on the test results, your healthcare provider can recommend the best treatment option.
Last reviewed by a Cleveland Clinic medical professional on 05/07/2021.
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