High Homocysteine: What It Is, Why It Matters, and How to Lower It

Homocysteine is an amino acid your body produces naturally as a byproduct of metabolising methionine. In a well-functioning methylation cycle it is efficiently recycled back into methionine. When that conversion is impaired — through MTHFR gene variants, low B vitamin status, or lifestyle factors — homocysteine accumulates.

What is a normal level?

Laboratory reference ranges generally place normal below 10 µmol/L, borderline at 10–15, elevated at 15–30, and severely elevated above 30. Some practitioners regard anything above 7–8 µmol/L as suboptimal, though this is not a universally agreed threshold.

What raises homocysteine

Common contributors include MTHFR variants that slow the methylation cycle, low folate, B12 or B6 status, heavy alcohol intake, smoking, chronic kidney disease, certain medications (including methotrexate and some anticonvulsants), and ageing.

Why it is monitored

Elevated homocysteine has been studied as an independent marker associated with cardiovascular and cerebrovascular risk, cognitive decline, mood disorders, peripheral nerve symptoms, clotting disorders and pregnancy complications. The VITACOG trial reported a reduced rate of brain atrophy in participants with mild cognitive impairment and elevated homocysteine who received B vitamins — a research finding, not a claim about any product.

Approaches to lowering it

The most commonly studied nutritional approach uses the three methylation B vitamins in their active forms: methylfolate (5-MTHF), methylcobalamin and P-5-P. These are supplied together in our range of methylated B vitamins. TMG (trimethylglycine) works through the separate betaine pathway and is sometimes used alongside them.

Reducing alcohol and smoking are also relevant. Testing homocysteine before and after any change is the only reliable way to know whether it made a difference — see also active vs inactive B vitamins and signs of impaired methylation.

NeuroThrive™ products are food supplements and are not intended to diagnose, treat, or cure any medical condition. If you have elevated homocysteine, please work with your GP.