Trimethylglycine (TMG) – Methyl donor used for homocysteine balance, liver support, and cellular hydration
Trimethylglycine, usually abbreviated as TMG and also known as betaine, is a naturally occurring compound found in foods such as beets, spinach, and whole grains. In dietary supplements, it is mainly used as a methyl donor, meaning it provides methyl groups for biochemical processes involved in homocysteine metabolism, liver function, and cellular protection.
Characteristics, Origin, and Composition
TMG is derived from glycine and carries three methyl groups, which makes it especially relevant for methylation pathways in the body. One of its best-known roles is helping convert homocysteine into methionine, which is why TMG is often included in cardiovascular-support and methylation-focused formulas. TMG also acts as an osmolyte, helping cells retain water and protect themselves against osmotic stress, particularly in liver, kidney, and muscle tissue.
Use in Dietary Supplements
TMG is commonly used:
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In methylation and homocysteine formulas, often alongside folate, vitamin B6, and vitamin B12.
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In liver-support products, because it is involved in fat metabolism and the normal handling of fats in the liver.
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In sports nutrition formulas, where it is used for cellular hydration, power output, and recovery; the evidence here is promising but less consistent than for classic performance ingredients like creatine.
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In general wellness products for people looking to support methylation or one-carbon metabolism.
TMG is sometimes confused with betaine HCl, but they are not the same. Betaine HCl is mainly used for stomach acid support, while TMG is primarily used for methylation support and osmoprotection.
Everyday Use and Well-Being
Typical supplemental amounts often range from 500 mg to 3000 mg per day, depending on the intended purpose and the overall formula. TMG is generally well tolerated, but higher intakes can sometimes cause digestive discomfort, and in some people long-term high use may unfavorably affect cholesterol markers. Dietary supplements do not replace a balanced diet or medical care; people with cardiovascular issues, liver conditions, or known methylation-related concerns should use it with professional guidance.
