TMG (Trimethylglycine)
Trimethylglycine (TMG), also known as betaine, is a naturally occurring compound found in foods like beets, spinach, and quinoa. It serves as one of the body's primary methyl donors, playing a central role in methylation reactions and homocysteine metabolism. TMG is widely used to support cardiovascular health markers and is a common companion supplement to NAD+ precursors like NMN and NR.
Expert Evidence
32 references from 2 experts
“That's where TMG comes in. TMG is trimethylglycine, meaning that it's got three methyl groups. It can donate those methyl groups to help convert homocysteine into methionine, and in the human clinical studies we can see that TMG lowers homocysteine levels.”
Why TMG (Betaine) Supplements Are So Popular
2:0830 references in 19 episodes from 2022–2025
Brad Stanfield is a strong advocate for TMG supplementation, taking it daily himself. He highlights its dual benefits for exercise performance and testosterone, as well as its role in lowering homocysteine levels, which may reduce Alzheimer's risk. He has not expressed any cautions or reasons to stop taking it.
Consumption
He takes 500mg to 1g of TMG daily, including as part of his MicroVitamin/Micrites formulation. He uses a lower dose (1g) due to limited long-term safety data, and also takes it to offset potential downsides of niacin supplementation.
Benefits
TMG improves exercise performance (VO2 max, sprint ability, one-rep max), boosts testosterone levels in athletes, and lowers homocysteine — a key risk factor for Alzheimer's disease and dementia. It works by donating methyl groups to convert homocysteine into methionine.
Best Practices
Most exercise performance studies use 2-5g daily, and TMG works best when combined with high-intensity exercise that poses high metabolic demands.
“Betaine basically helps as an osmolyte and as a cellular hydration factor. Water follows it into the cell and perhaps it keeps your cell hydrated longer. It also has some properties that show it might protect proteins from degrading in hot temperatures.”
Dr. Michael Ormsbee: Food Timing, Nutrition & Supplements for Fat Loss, Muscle Growth & Recovery
2:22:412 references in 1 episode
Galpin describes TMG (betaine) as an osmolyte that aids cellular hydration and may protect proteins from heat-induced degradation. He provides specific dosing from his research: initially 50 mg/kg body weight, later standardized to 3 grams for a firefighter study. No evidence of personal use, no cautions, and no discussion of interactions or long-term effects.
Side Effects
- Gastrointestinal discomfort at high doses
- Diarrhea (osmotic effect at very high doses)
- Possible increase in total and LDL cholesterol at high doses
- Fishy body odor in rare cases
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