An amino acid in your blood that rises when certain B-vitamins run low; high levels track with heart risk — but lowering them hasn’t reliably prevented heart attacks.
The plasma level of total homocysteine, an amino acid recycled using folate, vitamin B12 and B6.
Raised homocysteine is associated with cardiovascular disease. But the honest catch: trials show B-vitamins lower the number without reliably cutting heart attacks or deaths — so it’s a risk marker, not a proven treatment target for the heart.
< ~10–12 µmol/L (lab cut-offs range up to ~15). No single hard consensus line.
A mildly high value alone rarely changes heart management. It is more useful as a clue to a treatable B12/folate deficiency or reduced kidney function than as a cardiac lever.
Tends to be higher in men, and rises with age and worsening kidney function.
A notably high value is worth checking B12, folate and kidney function — the actionable finding is usually a vitamin deficiency, not the homocysteine number itself.