Just a simple question from an avid subscriber. Is the homocysteine in this article the same as the l-cysteine or acetyl-l-cysteine that people take for health reasons in pill form?

Paul A. Pagnato
McLean, Va.

L-cysteine and acetyl-l-cysteine are quite different from homocysteine. l-cysteine is a detoxifying agent and free radical scavenger that’s the mirror image of the amino acid cysteine. Acetyl-l-cysteine is the same compound with an acetyl molecule attached to make it more available to tissues. Homocysteine in high concentrations in blood has been linked with increased risk of atherosclerotic plaques in blood vessels, and it may have a toxic effect on cells lining such vessels. –N.S.