What Is Homocysteine?
Homocysteine is an amino acid produced when your body breaks down protein. Normally it is quickly converted into other substances with help from vitamin B12, B6 and folate. When these vitamins are low, homocysteine builds up in the blood.
Normal Homocysteine Range
| Level | Result |
|---|---|
| Normal | 5–15 µmol/L |
| Moderately elevated | 15–30 µmol/L |
| High | 30–100 µmol/L |
| Severely high | Above 100 µmol/L |
Why Is It Tested?
High homocysteine (hyperhomocysteinemia) is linked to an increased risk of blood clots, atherosclerosis, heart attack and stroke. It is sometimes ordered alongside a cardiac risk panel.
Common Causes of High Homocysteine
- Vitamin B12 deficiency
- Folate (vitamin B9) deficiency
- Vitamin B6 deficiency
- Kidney disease
- Hypothyroidism
- Genetic MTHFR mutation
- Smoking and heavy alcohol use
How to Lower Homocysteine
- Increase folate-rich foods (leafy greens, legumes, fortified grains)
- Vitamin B12 supplementation if deficient
- Vitamin B6 supplementation
- Reduce alcohol and quit smoking
- Treat underlying thyroid or kidney issues
Important: Homocysteine results should always be interpreted alongside vitamin B12, folate and overall cardiovascular risk by your doctor.