Betaine anhydrous, also known as trimethylglycine (TMG), is a naturally occurring compound found in various foods, particularly beets, spinach, and whole grains. It is classified as a methyl donor, meaning it contributes methyl groups (three hydrogen atoms bonded to a carbon atom) to other molecules in the body. Within the human body, betaine plays a crucial role in several metabolic pathways. One of its primary functions is in the methionine cycle, where it helps convert homocysteine into methionine. Homocysteine is an amino acid that, at elevated levels, is associated with an increased risk of cardiovascular disease. By facilitating its conversion to methionine, betaine helps maintain healthy homocysteine levels. Methionine, in turn, is a precursor for S-adenosylmethionine (SAMe), a universal methyl donor involved in numerous biochemical reactions, including the synthesis of neurotransmitters, DNA, and proteins. Beyond its role as a methyl donor, betaine also acts as an osmolyte, helping cells maintain water balance during osmotic stress, such as dehydration or high salt intake. This osmotic regulation function is important for cell volume maintenance and protein stability. As a supplement, betaine anhydrous is often marketed for its potential benefits in athletic performance, particularly endurance, and its broader implications for cellular health and longevity pathways, stemming from its roles in methylation and osmoprotection. It is categorized as a dietary supplement and is widely available without a prescription. Its half-life in the body is approximately 14 hours. (Examine.com, NIH ODS)
Deep dive
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Known interactions
Category rule: glp1 × supplement
Note
GLP-1 medications slow stomach emptying, changing how/when oral supplements absorb; rapid weight loss raises the importance of protein and micronutrients.
Time oral supplements when nausea is lowest; prioritize protein and micronutrients; discuss with your provider.
Category rule: supplement × medication
Note
Some supplements change how the body processes medications (absorption, liver enzymes, or additive effects).
Specific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist.
Frequently asked
Sources referenced
{Examine.com,"NIH Office of Dietary Supplements (ODS)",MedlinePlus,PubChem,"Mayo Clinic","Cochrane Library",DrugBank}
Stackwise compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician.
Related compounds
Others in the supplement category or studied for the same goals.
