Homocysteine
The optimal range for Homocysteine (Plasma Homocysteine) is commonly cited as <8 mcmol/L for cardiovascular and cognitive optimization, tighter than the standard lab reference range of <15 mcmol/L (lab cutoff). Methylation status marker - elevation reflects B-vitamin (B12, folate, B6) sufficiency and overall methylation capacity.
How Homocysteine ranges relate
The standard lab range vs the optimization-focused target. Illustrative trajectory shows what a 12-week improvement pattern looks like — not real user data.
What Homocysteine Measures
Homocysteine is an amino acid intermediate in methionine metabolism. Elevation reflects insufficient B12, folate, or B6 - the cofactors required to remethylate homocysteine back to methionine or convert it to cysteine. Persistently elevated homocysteine associates with cardiovascular disease, cognitive decline, and bone fracture risk.
While the causal link to CV events is debated (homocysteine-lowering trials with B-vitamins haven't reliably reduced CV events), elevated homocysteine remains a useful read on methylation health - relevant for B-vitamin sufficiency, MTHFR status, and overall metabolic resilience.
What Affects This Biomarker
Homocysteine is influenced by: B12 status, folate status, B6 status, MTHFR genotype (677TT raises modestly), kidney function (rises with declining eGFR), alcohol intake, smoking, hypothyroidism, and pharmacologic agents - methotrexate raises; metformin can lower B12 → raise homocysteine; some anticonvulsants raise; B-vitamin supplementation lowers reliably.
In the Context of Peptide Protocols
Pair with B12, folate (RBC folate ideally), and creatinine for full context. If elevated, methylated B-vitamins (methylcobalamin + L-methylfolate) typically lower it within 4–8 weeks. MTHFR variants warrant the methylated forms specifically. Long-term metformin use can drive B12 deficiency that raises homocysteine - monitor on GLP-1 + metformin combos.
Conditions That Track Homocysteine
Frequently Asked Questions
What does Homocysteine measure?
Homocysteine is an amino acid intermediate in methionine metabolism. Elevation reflects insufficient B12, folate, or B6 - the cofactors required to remethylate homocysteine back to methionine or convert it to cysteine. Persistently elevated homocysteine associates with cardiovascular disease, cognitive decline, and bone fracture risk.
What is the optimal range for Homocysteine?
The optimal range for Homocysteine is commonly cited as <8 mcmol/L for cardiovascular and cognitive optimization. The standard lab reference range is <15 mcmol/L (lab cutoff).
What affects Homocysteine levels?
Homocysteine is influenced by: B12 status, folate status, B6 status, MTHFR genotype (677TT raises modestly), kidney function (rises with declining eGFR), alcohol intake, smoking, hypothyroidism, and pharmacologic agents - methotrexate raises; metformin can lower B12 → raise homocysteine; some anticonvulsants raise; B-vitamin supplementation lowers reliably.
Where This Fits in Your Panel
Homocysteine is one marker on a fuller panel. The Peptide Blood Work Checklist lays out the complete baseline panel, what to add by protocol type, and when to retest.
See the full blood work checklist →Upload any lab PDF and MyProtocolStack maps your values to Homocysteine and 40+ other biomarkers. StackAI interprets the trend in context of your protocol.
Start tracking →Last reviewed: June 2026
Informational only - not medical advice. Reference ranges vary by lab and individual context. Work with a licensed provider to interpret your specific results.