What is the normal homocysteine level?

Optimal is below 10 µmol/L, 10–15 is the upper normal, above 15 is hyperhomocysteinemia. The level is slightly higher in men and the elderly, lower in pregnancy.

Why is high homocysteine dangerous?

It’s an independent risk factor for atherosclerosis, thrombosis, heart attack and stroke, and for pregnancy complications. It damages the vessel wall, but is not itself a diagnosis.

Why does homocysteine rise?

Most often from folate and vitamin B12 deficiency, MTHFR genetic variants, kidney disease, smoking and some drugs. So a high level prompts checking B12 and folate.

How do I lower homocysteine?

Usually replenishing folic acid and vitamins B12/B6 plus lifestyle changes help, but a doctor tailors the plan to the cause. Lowering the number alone doesn’t replace addressing other risk factors.

Should everyone test homocysteine?

Mass screening of healthy people isn’t recommended. Testing is appropriate with cardiovascular risk, thrombosis, recurrent pregnancy loss or B12/folate deficiency — as directed by a doctor.

Homocysteine: normal range and assessment

Homocysteine is an amino acid whose elevated level is linked to risk for blood vessels and the heart. Enter the value from your blood test (µmol/L) — the calculator compares it with the bands: optimal, borderline and hyperhomocysteinemia, and explains what it may indicate.

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Homocysteine norm

Guidance for adults. The level is slightly higher in men and the elderly, and lower in pregnancy. Assess it together with B12, folate and kidney function.

Homocysteine, µmol/L	Assessment
below 10	Optimal
10–15	Upper normal / borderline
15–30	Moderately elevated
above 30	Markedly elevated

What homocysteine is and the normal range

Homocysteine is an intermediate amino acid in methionine metabolism. Normally the body clears it quickly with vitamins B12, B6 and folate. Below 10 µmol/L is optimal; 10–15 is the upper border, above 15 is hyperhomocysteinemia.

It runs slightly higher in men, the elderly and in kidney disease — this is factored into interpretation.

Why high homocysteine matters

Elevated homocysteine is an independent risk factor for atherosclerosis, thrombosis, heart attack and stroke: it damages the inner lining of blood vessels. It’s also linked to pregnancy complications and cognitive decline.

Important: it’s a risk factor, not a diagnosis. Lowering homocysteine alone doesn’t guarantee lower cardiovascular risk — all risk factors need to be addressed together.

Causes and how to lower it

A common cause is folate and vitamin B12 deficiency, plus genetic MTHFR variants, kidney disease, smoking and some medications. So high homocysteine is a reason to check B12 and folate.

Correction (folic acid, B12/B6, lifestyle) is prescribed by a doctor based on the cause, not “just in case”. The calculator only shows whether the value is within the norm.

Frequently asked questions

Optimal is below 10 µmol/L, 10–15 is the upper normal, above 15 is hyperhomocysteinemia. The level is slightly higher in men and the elderly, lower in pregnancy.
It’s an independent risk factor for atherosclerosis, thrombosis, heart attack and stroke, and for pregnancy complications. It damages the vessel wall, but is not itself a diagnosis.
Most often from folate and vitamin B12 deficiency, MTHFR genetic variants, kidney disease, smoking and some drugs. So a high level prompts checking B12 and folate.
Usually replenishing folic acid and vitamins B12/B6 plus lifestyle changes help, but a doctor tailors the plan to the cause. Lowering the number alone doesn’t replace addressing other risk factors.
Mass screening of healthy people isn’t recommended. Testing is appropriate with cardiovascular risk, thrombosis, recurrent pregnancy loss or B12/folate deficiency — as directed by a doctor.

Decode your vascular-risk panel

Upload your tests — AI assesses homocysteine together with cholesterol, B12 and folate and explains clearly what to do about cardiovascular risk.

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This calculator is for reference and information only and is not a diagnosis. High homocysteine and its cause are assessed by a doctor from B12, folate and kidney function.