Homocysteine

What is Homocysteine?

Homocysteine is a sulfur-containing amino acid formed during the metabolism of methionine (from dietary protein). It is normally recycled back to methionine (requires B12 and folate) or converted to cysteine (requires B6). Raised homocysteine reflects impaired methylation — one of the body's most important biochemical processes.

What might a high or low Homocysteine mean?

Raised homocysteine is associated with cardiovascular disease, stroke, and clotting. It can affect the blood-vessel lining and oxidative balance, and is often linked to B-vitamin (B12, folate, B6) status.

What is the typical reference range for Homocysteine?

The general-population reference range shown here is 5 – 15 umol/L. Reference ranges describe the general population and are not a personal target — discuss your results with your physician.

What can affect Homocysteine?

It may be higher with: Vitamin B12 deficiency (most common cause), Folate deficiency, Vitamin B6 deficiency, Chronic kidney disease (reduced clearance), Hypothyroidism, Genetic MTHFR variants (C677T, A1298C), Medications (methotrexate, phenytoin, carbamazepine), High methionine diet without adequate B vitamins, Coffee excess, Aging. It may be lower with: Vitamin B12 supplementation (methylcobalamin preferred), Folate (methylfolate preferred, especially with MTHFR variants), Vitamin B6 (pyridoxal-5-phosphate, active form), Betaine (trimethylglycine), Reducing coffee intake, Treating hypothyroidism.