Optimal Ranges
What is the optimal range for Homocysteine?
Clinical (NHS) Range
<15 µmol/L
µmol/L
Performance-Optimised Range
<8 µmol/L
µmol/L
| Range | Value | Unit |
|---|---|---|
| Clinical (NHS) reference range | <15 µmol/L | µmol/L |
| Performance-optimised range | <8 µmol/L | µmol/L |
The clinical range defines what is considered medically “normal” — broad enough to cover 95% of the population. The performance range reflects where research and clinical experience suggest most people feel and function at their best. A result in either range suggests typical status and is not a diagnosis; any individual reading should be interpreted by a qualified clinician.
Why It Matters
Why Homocysteine matters for performance
Elevated homocysteine is an independent risk factor for cardiovascular disease, stroke, blood clots, and cognitive decline. It damages the endothelium (arterial lining), promotes oxidative stress, and impairs nitric oxide production — reducing blood flow and exercise performance. Critically, homocysteine is a functional marker of B12, folate, and B6 status — elevated levels often indicate deficiency in one or more of these vitamins even when serum levels appear 'normal'. It's particularly important for men with the MTHFR C677T variant (~40% of the population), who have impaired folate metabolism and tend to run higher homocysteine.
Symptoms
What are the symptoms of low or high Homocysteine?
Low / Deficiency
- Low homocysteine is not a concern — lower is better
High / Excess
- Often asymptomatic until cardiovascular event
- Fatigue and brain fog (due to underlying B vitamin deficiency)
- Blood clots (deep vein thrombosis)
- Early cognitive decline
- Poor exercise recovery
Dietary Sources
Which foods support Homocysteine levels?
Supplementation
How do you improve Homocysteine levels?
The homocysteine-lowering protocol is well-established: methylfolate (5-MTHF, 800mcg-5mg daily), methylcobalamin (B12, 1,000mcg daily), and pyridoxal 5'-phosphate (B6, 25-50mg daily). This combination addresses all three recycling pathways. Betaine (trimethylglycine, 500-3,000mg daily) provides an additional pathway for homocysteine conversion. For MTHFR carriers, methylated forms are essential — folic acid (synthetic) may not convert efficiently. Response is typically seen within 4-8 weeks. If homocysteine remains elevated despite supplementation, investigate kidney function (the kidneys are the primary excretion route).
Testing
How is Homocysteine tested in the UK?
Homocysteine is measured from a blood sample. With Helvy, that means a finger-prick kit taken at home and posted to a UKAS-accredited UK laboratory, with results in around 5 days, reviewed by a qualified clinician. Your result is reported against both the clinical range (<15 µmol/L) and the performance-optimal range (<8 µmol/L), so you can see not just whether you are “normal” but whether you are optimal. If you make a change, retest after 8-12 weeks to confirm it worked.
Research
Key study
Homocysteine and cardiovascular disease: evidence on causality from a meta-analysis
Wald DS, Law M, Morris JK
BMJ (2002)
DOI: 10.1136/bmj.325.7374.1202Related Biomarkers
Related Guides
Explore Homocysteine in depth
Test your Homocysteine levels
Homocysteine is included in the Helvy 50+ biomarker panel. Get your results in 5 days with a personalised protocol.
Order Your TestThis content is for educational purposes only and does not constitute medical advice. Your data suggests areas for optimisation, but any concerns should be discussed with a qualified healthcare professional. If your results flag values outside safe ranges, we recommend consulting your GP.