Betaine (TMG)
A compound that helps lower homocysteine and supports methylation.
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What it is
Betaine, or trimethylglycine, is a compound found in beets and grains that donates methyl groups, notably helping convert homocysteine (an amino acid linked to cardiovascular risk) into methionine.
How it works
Betaine (trimethylglycine) donates methyl groups, notably helping convert homocysteine — an amino acid linked to cardiovascular risk — into methionine. That methylation role is the basis for its homocysteine-lowering effect; it's also studied for exercise performance.
What it's been studied for
Taken to support healthy homocysteine levels and, among athletes, performance.
What the evidence shows
Betaine reliably lowers homocysteine. Its cardiovascular-outcome and performance claims are less settled — performance results in particular are mixed.
Who should consider it
It's used to support healthy homocysteine levels and, among athletes, performance. It reliably lowers homocysteine, but its cardiovascular-outcome and performance claims are less settled, and it can raise cholesterol.
Amounts commonly studied
Homocysteine studies use higher doses; performance studies commonly use around 2.5 g per day.
How to take it
Homocysteine studies use higher doses; performance studies commonly use about 2.5 g per day. It's a powder or capsule, distinct from betaine HCl (used for stomach acid).
Forms & absorption
TMG powder or capsules; distinct from betaine HCl, which is used for stomach acid.
Food sources
Beets, spinach, whole grains (wheat bran), and quinoa.
Safety & interactions
Generally well tolerated; high doses may raise LDL cholesterol in some people and cause digestive upset.
Myths & what it won't do
Myth: betaine is a proven performance enhancer. Reality: performance results are mixed. Myth: it's purely heart-protective. Reality: while it lowers homocysteine, it can moderately raise LDL cholesterol in some people, so it isn't straightforwardly heart-healthy.
Common questions
- Does betaine improve athletic performance?
- Performance studies are mixed; it reliably lowers homocysteine, but the ergogenic evidence is inconsistent.
- Is it good for the heart?
- It lowers homocysteine, but it can also moderately raise LDL cholesterol in some people, so the net cardiovascular picture is unsettled.
- Is it the same as betaine HCl?
- No — TMG (this betaine) is for methylation/homocysteine; betaine HCl is used to add stomach acid.
The amounts listed here are what published research has used — not a prescription or a recommended dose for you. Confirm anything you plan to take with your own healthcare provider, especially if you take medications, are pregnant or nursing, or have a health condition.
Related goals
Research on Betaine (TMG)
Recommendations on this page are informed by published research. This is educational information, not medical advice.
- Zawieja EE, Zawieja B, Chmurzynska A. Betaine Supplementation Moderately Increases Total Cholesterol Levels: A Systematic Review and Meta-Analysis. J Diet Suppl. 2021;18(1):105-117. View study →Note: Betaine reliably lowers homocysteine but was found to moderately raise total and LDL cholesterol — a reason for caution at higher doses.