Homocysteine
Homocysteine tells you whether your B-vitamin recycling system is working properly. If it’s not, you’re at higher risk for heart disease and cognitive decline. Extremely common issue in Indian vegetarians.
Your body produces homocysteine as a byproduct of protein metabolism. Normally, B12, folate, and B6 recycle it back into useful molecules. When these vitamins are low — as they often are in vegetarians — homocysteine builds up and damages blood vessels and brain tissue.
What is the homocysteine test?
Homocysteine is an amino acid your body makes when it processes protein. Normally, three B-vitamins — B12, folate, and B6 — recycle it into harmless or useful molecules. When any of these vitamins is low, homocysteine accumulates in your blood. That buildup damages your blood vessel walls, promotes clotting, and harms brain tissue.
The reason this matters so much in India: B12 comes almost exclusively from animal products. If you’re vegetarian (a large portion of India’s population), you’re structurally at risk for B12 deficiency and elevated homocysteine.
What your number means
| Homocysteine (µmol/L) | Category | What to do |
|---|---|---|
| <7 | Optimal | Your methylation is working well. Maintain B-vitamin intake. |
| 7–10 | Good (longevity target) | Ensure dietary B12 adequacy. Monitor annually. |
| 10–15 | Borderline elevated | Start methylcobalamin 1000mcg + methylfolate 400–800mcg + P5P 50mg daily. |
| 15–30 | Elevated | Same supplements at higher doses. Add TMG 1000–1500mg. Check kidney function. |
| >30 | Very high | Physician evaluation. Rule out genetic enzyme defects. |
How to improve it
Methylcobalamin (B12) 1000 mcg/day + methylfolate (5-MTHF) 400–800 mcg/day + P5P (active B6) 25–50 mg/day. Add TMG 500–1500 mg/day as a backup methyl donor.
Use methylcobalamin, not cyanocobalamin. Use methylfolate, not folic acid — especially important if you carry the MTHFR variant (40–50% of Indians do). Expect 20–40% reduction at 3 months. Retest to confirm.
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eterni shows you whether your B-vitamin protocol is actually working — not just guessing.
Get early accessFrequently Asked Questions
What is a normal homocysteine level?
Labs report below 15 as normal. The longevity optimal is below 10 — ideally 6–9. Above 10 warrants supplementation. Above 15 is elevated and associated with significant cardiovascular and cognitive risk.
Does B12 lower homocysteine?
Yes — methylcobalamin is one of the three primary regulators. In B12-deficient people (very common in Indian vegetarians), supplementing 1000mcg/day can reduce homocysteine 20–40%. Use methylcobalamin, not cyanocobalamin.
What is MTHFR and should I worry about it?
MTHFR is an enzyme that activates folic acid. The C677T variant — present in 40–50% of Indians — reduces its activity, impairing homocysteine clearance. If you have this variant, use methylfolate (5-MTHF) instead of regular folic acid.
Can high homocysteine cause memory problems?
Yes — elevated homocysteine is independently linked to cognitive decline, brain atrophy, and Alzheimer’s. The VITACOG trial showed that B-vitamin supplementation targeting homocysteine significantly slowed brain shrinkage. Keeping it below 10 is one of the most evidence-backed strategies for brain health.
How it’s measured
A simple blood draw, ideally fasted overnight. Most Indian labs (SRL, Metropolis, Dr Lal PathLabs) offer it for ₹500–1,000. Pair with serum B12, active B12 (holotranscobalamin), and folate for a complete methylation picture.
The MTHFR connection
40–50% of Indians carry the MTHFR C677T variant (heterozygous), and 10–15% carry it in homozygous form. This reduces the enzyme’s activity by 30–65%, meaning your body can’t properly activate folic acid. The fix is simple: use 5-MTHF (methylfolate) instead, which bypasses the defective enzyme entirely.
India-specific context
India has among the highest rates of elevated homocysteine globally. The combination of widespread vegetarianism (low B12 intake) and high MTHFR variant prevalence makes this one of the most clinically significant and underdiagnosed metabolic issues in the country.
Connected supplements
Methylcobalamin (B12), methylfolate (5-MTHF), P5P (active B6), and TMG (trimethylglycine) are the four key interventions. A methylated B-complex containing all three active B-vitamins is the most practical approach.
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eterni connects your lab results, supplements, and retests — so you can see the trajectory, not just a snapshot.
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