Homocysteine
What This Test Measures
Amino acid byproduct; marker of methylation and B-vitamin status
Conventional vs. Functional Optimal Range
The gap between these ranges is why you feel terrible with "normal" labs. Conventional medicine waits for disease. Functional medicine optimizes for health.
Gabriel's Take
Higher homocysteine is linked to heart disease, stroke and cognitive decline. Gabriel's optimal band is 5-7, much tighter than the lab cutoff of 15. Common causes: low B12, folate or B6, kidney disease, an underactive thyroid, smoking, and MTHFR variants. Lowering homocysteine with B vitamins usually hasn't been shown to lower heart attack or stroke risk, so the goal is to find the cause; any form of folate can work, including folic acid (CDC). Full guide: askgabriel.com/guides/homocysteine-blood-test.
When This Test Is High
Cardiovascular disease, stroke, dementia, B-vitamin deficiency
When This Test Is Low
Usually not clinically significant
Related Conditions
Heart disease, thrombosis, cognitive decline
Recommended Follow-Up
Check B12, folate and MMA, plus kidney and thyroid tests when they fit; replace a low B vitamin with your clinician's advice; recheck after a change