Homocysteine: what it means.
Elevated levels signal a methylation/B-vitamin shortfall and raise cardiovascular risk.
Written to our editorial standards · reviewed against published research· Updated 2 Jun 2026
Typical reference bands (µmol/L)
Optimalunder 7 µmol/L
Borderline10-15 µmol/L
Highover 15 µmol/L
Ranges vary by laboratory, age, and sex, your lab's own reference range always takes precedence.
Common causes
- A shortfall of folate, B12, or B6
- MTHFR genetic variants
- An underactive thyroid
- Reduced kidney function
What it can feel like
- No direct symptoms; elevated levels raise cardiovascular and cognitive risk
Who should test
Useful with cardiovascular or cognitive concerns, or a known MTHFR variant.
Supplements that help lower Homocysteine
Evidence-led, and only a piece of the picture, diet, lifestyle, and your clinician matter most.
B6, B12, folate (as methylfolate), and TMG supply the methyl groups that clear homocysteine into harmless compounds, often lowering it within weeks.
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Common questions
What does a high Homocysteine mean?
Common drivers include a shortfall of folate, B12, or B6; mTHFR genetic variants; an underactive thyroid. A result outside the optimal range is best read in context: discuss it with your clinician, who can weigh the full picture and your lab's own reference range.
What supplements help lower Homocysteine?
Evidence-led options include B-Complex, Methylfolate, Methyl-B12, Vitamin B6, TMG. They support, but don't replace, diet, lifestyle, and medical care.
Educational use only, not medical advice or diagnosis. Always interpret lab results with a qualified clinician.