Trimethylglycine Reduces Homocysteine and Protects DNA Dietary Supplement Suitable for Vegetarians/Vegans Non GMO Certified by NSF TMG Crystals provides trimethylglycine (a.k.a., anhydrous betaine), an important methyl donor. Methyl donors, such as TMG and folic acid, are required for converting homocysteine, an oxidizing metabolite, back into the amino acid methionine and for the accurate synthesis of DNA and RNA, which is essential for the production of normal cells.