Homocysteine is a toxic transient metabolite of methionine and is a significant heart risk factor. Homocysteine is reduced back to biologically safe methionine by methyl groups donated by TMG and enzymes that require Folic Acid, B12 and methyl groups or back to cysteine by B6.

Methylation is inhibited by inadequately functioning key enzymes, excessive protein and fat intake, poor diet, inadequate intake of methyl groups, coffee, alcohol or by smoking.