Homocysteine

Homocysteine is an amino acid produced during metabolism and recycled with the help of folate and vitamins B12 and B6. When those are low (or in certain genetic conditions), homocysteine rises.

Elevated homocysteine is associated with higher cardiovascular, stroke, and cognitive-decline risk. But there is a crucial caveat: lowering homocysteine with B-vitamins has generally NOT reduced cardiovascular events in trials — so it is a risk marker, not a proven treatment target.

1. 1

   FoundationCardiovascular HealthThe best place to understand what actually prevents heart disease.
2. 2

   ConditionAtherosclerotic Cardiovascular DiseaseThe disease behind most heart attacks and strokes
3. 3

   Body SystemCardiovascularHeart function, blood pressure, and circulatory health.
4. 4

   BiomarkerVitamin B12A reversible cause of cognitive and neurological symptoms

1. Measure it
2. Understand your result
3. See what raises and lowers it
4. Apply evidence-based interventions
5. Recheck on your review cadence

An orientation to how this topic is typically approached — not medical advice.

A high homocysteine flags elevated vascular and cognitive risk and can indicate B-vitamin deficiency worth correcting. It does not, by itself, justify treating the number to lower cardiovascular risk — the evidence for benefit is lacking.

• Fasting plasma total homocysteine
• Checked with B12/folate when elevated

Homocysteine is a consistent risk marker for vascular and cognitive outcomes, but randomized trials show that lowering it with B-vitamins does not reduce cardiovascular events — a key distinction between association and treatable cause.

• Homocysteine-lowering trial meta-analyses (B-vitamins; null CV outcomes)
• AHA scientific statements

Sources are named authoritative guidelines and scientific bodies. Biomarker pages present established clinical context; calibrated evidence verdicts on specific interventions live in the linked Signal Records.