Trimethylglycin

Trimethylglycin, commonly known as trimethylglycine or glycine betaine, is an organic compound with the formula C5H11NO2. It is the N-trimethylated derivative of glycine and exists as a zwitterion under physiological conditions. The compound is highly water-soluble and occurs naturally in a variety of organisms.

In nature, trimethylglycin serves primarily as an osmolyte, helping cells cope with osmotic and salt stress. It accumulates in plants, bacteria, and some animals to protect cellular processes during drought, salinity, or temperature fluctuations. In humans and other mammals, it is also present in small amounts and provides osmotic support in tissues such as the kidney and liver.

Trimethylglycin is notable for its role as a methyl donor in the methionine cycle. It donates a methyl group to homocysteine via the enzyme betaine-homocysteine methyltransferase (BHMT), forming methionine and dimethylglycine. This pathway complements remethylation by 5-methyltetrahydrofolate-dependent methionine synthase.

Dietary sources of glycine betaine include sugar beets (and beet-derived products), spinach, cereals, and some seafood. It is also widely sold as a dietary supplement, marketed for liver health and homocysteine management. Evidence for clinical benefits beyond modest reductions in homocysteine is mixed, and it is not approved as a drug for any specific disease.

Safety and regulation: trimethylglycin is generally regarded as safe at typical supplement doses but can cause gastrointestinal upset or body odor in some individuals. As with any supplement, usage should follow product guidelines and medical advice, particularly in individuals with kidney disorders or those taking medications affecting methylation pathways.