Trimethylglycine (TMG) is identical to DMG (B15), except that it contains three methyl groups instead of two. After ingestion TMG is rapidly converted into DMG by the liver, providing the body with all the benefits of DMG, as well as detoxifying homocysteine, a by product of methionine metabolism that is a powerful pro-oxidant and free-radical generator known to be a leading cause of heart disease.
If one gets adequate amounts of B6, either from foods or supplements, much of the bodys homocysteine is converted into cystathione, an antioxidant and free-radical deactivator.
About half of our homocysteine is detoxified by this process. The other half is detoxified by a process called transmethylation. One way this happens is that 5-methyltetrahydrofolate, which we make from folic acid, donates its methyl group to the homocysteine and thereby converts it to the essential amino acid methionine. Homocysteine is nothing more than methionine deprived of its methyl group.
Another way that homocysteine is converted to methionine is through transfer of the methyl group from trimethlglycine (TMG). We get an additional benefit from this because TMG, in losing its methyl group, becomes DMG. In brief, this simple action detoxifies homocysteine, recycles methionine and supplies B15.
TMG is also called betaine. We avoid this name because betaine is commonly sold in health food stores in it’s hydrochloride form as a hydrochloric acid supplement for people with weak digestive acids. This is not the desired form for the purposes described above. It is very acidic, must be taken only with meals and can otherwise cause severe gastric irritation. The desired material is free-base betaine, which tastes mildly sweet and causes no untoward side effects. In order to make a clear distincion and avoid confusion, we call the acid supplement betaine HCI and the detoxifying nutrient TMG.