Homocysteine Blood Test

Measures homocysteine — an amino acid that at elevated levels is an independent risk factor for cardiovascular disease, stroke, cognitive decline, and accelerated ageing. Homocysteine is a direct marker of methylation efficiency, the biochemical process responsible for DNA repair, neurotransmitter production, and detoxification. Elevated levels indicate impaired B12, folate, or B6 metabolism and are modifiable through targeted supplementation.

Homocysteine is an amino acid intermediate in the methylation cycle — a biochemical pathway essential for DNA repair, neurotransmitter production, detoxification, and cardiovascular health. Elevated homocysteine is an independent risk factor for cardiovascular disease, stroke, dementia, and pregnancy complications including neural tube defects and recurrent miscarriage. The body normally converts homocysteine back to methionine (using B12 and folate) or to cysteine (using B6). When these B vitamin cofactors are insufficient, or when genetic variants like MTHFR reduce enzyme efficiency, homocysteine accumulates. Elevated levels damage arterial endothelium, promote blood clotting, increase oxidative stress, and impair nitric oxide production — the molecule responsible for blood vessel dilation. Homocysteine is one of the most actionable biomarkers in preventive medicine because elevated levels are almost always correctable. Targeted supplementation with methylfolate, methylcobalamin (B12), and pyridoxal-5-phosphate (B6) typically normalises levels within weeks. However, the specific B vitamin forms matter — people with MTHFR variants cannot efficiently use folic acid (the synthetic form) and require methylfolate instead. This test requires an 8-12 hour fast for accurate measurement. ClearLabs delivers results within 2-3 business days, displayed against optimal ranges. Many longevity practitioners consider optimal homocysteine to be below 7 micromol/L — significantly lower than the conventional upper limit of 15. For anyone with a family history of heart disease, stroke, or dementia, or known MTHFR variants, this is a foundational biomarker worth tracking over time.