S-Adenosylhomocysteine Unit Converter

S-Adenosylhomocysteine (SAH) is a sulfur-containing molecule produced every time your body performs a methylation reaction. Methylation is one of the most common chemical modifications in the body, used to regulate DNA expression, build neurotransmitters, process hormones, and maintain cardiovascular health.

SAH is the direct by-product of S-Adenosylmethionine (SAM), the body's primary methyl donor. When SAM donates its methyl group to a target molecule, it becomes SAH. The body then breaks SAH down into adenosine and homocysteine to keep the cycle moving.

When SAH accumulates, it acts as a potent inhibitor of the very methylation enzymes that produced it. The ratio of SAM to SAH (called the "methylation index") is considered the best single measure of the body's overall methylation capacity.

SAH is produced in every cell that performs methylation. It forms when SAM donates a methyl group to any substrate, making it a universal by-product of the methylation cycle. The liver is the primary site of methionine metabolism, while the kidneys are the principal organ responsible for SAH disposal.