Betaine functions very closely with choline, folic acid, vitamin B12, and a form of the amino acid methionine known as S-adenosylmethionine (SAMe). All of these compounds function as “methyl donors.” They carry and donate methyl molecules to facilitate necessary chemical processes. The donation of methyl groups by betaine is very important to proper liver function, cellular replication, and detoxification reactions. Betaine also plays a role in the manufacture of carnitine and serves to protect the kidneys from damage.