What this marker measures
Homocysteine is considered an independent cardiovascular risk factor, though clinical trials have not consistently shown that lowering it with B vitamins reduces cardiovascular events. It remains useful for identifying B vitamin deficiency and rare metabolic conditions (homocystinuria).
High or low: what it can mean
High Homocysteine
Elevated homocysteine is associated with increased cardiovascular risk and, at very high levels, with venous thrombosis. The most common causes are low B12, low folate, low B6, kidney disease, or genetic factors.
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Low Homocysteine
Low homocysteine is not clinically significant and may reflect high B vitamin intake.
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Lifestyle considerations
- •Adequate B12, folate, and B6 are the key nutrients for keeping homocysteine in a healthy range
- •Avoiding excess methionine (found in high amounts in red meat) may also help
Frequently asked questions
What is Homocysteine?
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Homocysteine is an amino acid produced during the breakdown of methionine. It is metabolised using vitamins B6, B12, and folate, so elevated levels can reflect deficiencies of these vitamins.
What does Homocysteine measure?
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Homocysteine is considered an independent cardiovascular risk factor, though clinical trials have not consistently shown that lowering it with B vitamins reduces cardiovascular events. It remains useful for identifying B vitamin deficiency and rare metabolic conditions (homocystinuria).
What does high Homocysteine mean?
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Elevated homocysteine is associated with increased cardiovascular risk and, at very high levels, with venous thrombosis. The most common causes are low B12, low folate, low B6, kidney disease, or genetic factors.
What does low Homocysteine mean?
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Low homocysteine is not clinically significant and may reflect high B vitamin intake.
What supports healthy Homocysteine levels?
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Adequate B12, folate, and B6 are the key nutrients for keeping homocysteine in a healthy range. Avoiding excess methionine (found in high amounts in red meat) may also help
Related biomarkers
Editorial note
LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.
Educational content · Editorially reviewed for clarity · Last updated
Common sources used for lab-test education
Not medical advice
This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.