Betaine dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
Six grams a day lowers fasting homocysteine by 20 percent in healthy adults.
Evidence grade for Betaine: Moderate. The rule: at least one finished study in people, and at least 100 people who took it. The sum on this page: 3 completed trials, 170 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 170
- Human studies
- 3
- Found nothing
- 1
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
3 completed trials, 170 people given it
4 effects reported, 2 unwanted, 2 wanted, by people using it, not a trial
Goal pages: Heart and circulation
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
Betaine, also sold as TMG, is a natural compound your body uses for chemical tagging. It lowers homocysteine, a blood marker linked to heart disease. It is a supplement, and a prescription drug for one rare inherited disease.
What people take it for
- Lowering homocysteine.
- Heart health.
- Gym performance.
- Methylation support in longevity stacks.
What studies in people showed
The biggest test of the idea behind it had 12,064 heart attack survivors. B vitamins cut their homocysteine by 28 percent. Heart attacks and strokes did not drop. Betaine itself lowers homocysteine well. In 76 healthy adults, 6 grams a day cut it by 20 percent. But in the same research, 6 grams a day raised LDL, the bad cholesterol. For homocystinuria, a rare inherited disease, it is an approved drug.
What people report
Reports, not study results
The good
- It lowers homocysteine reliably. You can see the number move.
- It is an approved, well-tested medicine for homocystinuria.
The bad
- It raises LDL cholesterol and triglycerides, starting within two weeks.
- Lowering homocysteine did not prevent heart attacks in the big studies.
- We have not collected user reports on this one yet.
Where these come from: The studies and reviews on this page. We have no forum reports on this one.
My bottom line
Lowering homocysteine is not the same as protecting your heart. If you take it, run a lipid panel before and after. If your LDL goes up, stop.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals Betaine has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Cholesterol and blood fats151 people · 1 study · 1 found nothing
- Heart attacks and strokesno headcount stated · 1 study
34 of the 36 indexed goals have no study of any kind behind Betaine
No study in people, animals or cells on this page reports a result for these. That does not prove Betaine does nothing for them. It does mean anything you have heard about Betaine and one of these did not come from a study cited here.
Show full evidence
What is Betaine?
Six grams a day lowers fasting homocysteine by 20 percent in healthy adults. In the same studies it raises LDL, the bad cholesterol, by 0.36 mmol/L. Studies that lowered homocysteine another way and then counted heart attacks found nothing. In 12,064 heart attack survivors, homocysteine fell 28 percent, and heart and blood vessel events did not drop.
Betaine does exactly what it says on the bottle. What it says on the bottle turns out not to be the point. It is the cleanest example of that on this page.
It lowers homocysteine, reliably, and more at higher doses. Homocysteine is a blood marker linked to heart disease. In 76 healthy adults given 1.5, 3 or 6 grams a day for six weeks, fasting homocysteine fell 12, 15 and 20 percent more than on a dummy. The spike after a dose of the amino acid methionine fell by 23, 30 and 40 percent. Those are large, steady effects, at amounts inside what a normal diet can supply.
The same research team then pooled the blood fat results from their betaine studies. They found something the first paper had no reason to mention. At 6 grams a day for six weeks, betaine raised LDL cholesterol by 0.36 mmol/L, roughly 14 mg/dL. It raised triglycerides by 0.14 mmol/L, and the ratio of total to good cholesterol by 0.23. Lower doses raised LDL too, but not clearly. The rise showed up within two weeks. The team's own conclusion is that the bad effects on blood fats may cancel out any heart benefit from lowering homocysteine. A later review pooled six studies at four grams a day or more. It found total cholesterol rose 0.34 mmol/L.
Underneath both findings is a bigger question: does lowering homocysteine do anything? That has been tested hard. In 12,064 heart attack survivors followed for 6.7 years, folic acid and vitamin B12 lowered homocysteine by 28 percent. Major heart and blood vessel events hit 25.5 percent of the treated group and 24.8 percent of the dummy group. The Cochrane review of homocysteine-lowering supplements found no difference from a dummy for heart attacks or deaths from any cause. It found a small benefit for stroke. It concluded more studies are unlikely to change the answer.
None of this touches the one place betaine has a proven medical role. Betaine anhydrous is an approved prescription medicine for homocystinuria. That is an inherited disease where homocysteine is not a risk marker but a poison, at levels far above normal. That is a real problem with a real result to measure. It is a completely different situation from taking TMG because you saw it in a stack.
How does Betaine work?
Betaine hands a small chemical tag, a methyl group, to homocysteine. That turns homocysteine back into methionine, a normal amino acid. This is a second route, alongside the one that uses folate and vitamin B12. It runs mainly in the liver and kidneys. That is why betaine lowers homocysteine even when folate levels are fine. Betaine also helps cells hold their water and size under stress. That is the basis of most sports performance claims. The cholesterol effect is thought to come from the same chemistry. Pushing this reaction changes how the liver makes and ships out certain fats, including the particles that carry cholesterol. That is a likely route, not a proven one. The studies that found the effect were not built to explain it.
What have studies in people found about Betaine?
A lot of data, and it contradicts itself in a useful way. Betaine's effect on homocysteine is one of the best-proven effects of any supplement. Its effect on blood fats points the other way. And the idea that links lowering homocysteine to better health was tested at huge scale, and did not hold.
- SEARCH study, 12,064 heart attack survivors: homocysteine fell 28 percent with B vitamins. Heart and blood vessel events did not drop over 6.7 years, 25.5 percent against 24.8 percent.
- Cochrane review, 2017: lowering homocysteine did not change heart attacks or deaths from any cause. It had a small good effect on stroke.
- A review of six studies at 4 grams a day or more: total cholesterol rose 0.34 mmol/L. There was no clear pooled effect on LDL alone.
- Pooled across three betaine studies with 151 people: LDL cholesterol rose 0.36 mmol/L and triglycerides 0.14 mmol/L at 6 grams a day, visible within two weeks.
- 76 healthy adults, six weeks: fasting homocysteine fell 12, 15 and 20 percent on 1.5, 3 and 6 grams a day.
- Betaine anhydrous is an approved prescription treatment for homocystinuria, where homocysteine is the disease itself, not a risk marker.
- No study has measured lifespan, healthy ageing or any ageing measure with betaine.
What this does not tell you: The homocysteine and cholesterol results come mostly from one research team's short studies in healthy volunteers, partly paid for by the food industry, which they disclosed. The two pooled cholesterol reviews disagree on whether the LDL rise holds up. That disagreement should not be settled by picking the friendlier one. Most important, the heart studies that knock out the whole idea used B vitamins, not betaine. Nobody has run a heart attack and stroke study of betaine itself. On current evidence, nobody has a reason to.
The state of the research
A stand-in marker is a lab number used in place of the thing you actually care about. The idea is that if you move the number, you move the health result. That idea has failed often enough that it should be treated as a claim, not a fact. Homocysteine is the classic case. In studies that watch people, high homocysteine strongly predicts heart disease. Several cheap supplements can lower it reliably. But when studies lowered it and then counted heart attacks, the heart attacks did not go down. The lesson is not that markers are worthless. It is that a study reporting a marker has answered a smaller question than the one the buyer is asking. The page should say which question was answered.
Betaine belongs on this site because it is where the gap between marker and real result was measured, not just argued about. Homocysteine had everything a stand-in marker is supposed to have. In studies that watch people, higher levels tracked with more disease. There was a believable reason, damage to blood vessels. And there were cheap, reliable ways to lower it. Then the studies were run, in tens of thousands of people, and the heart attacks did not fall. That result is why this archive treats a marker as a signal to stop, not as a goal.
Two practical points follow. If you take betaine to lower homocysteine, you can watch the number move, and you will be watching something real. The best evidence says it will not change your heart risk. And if you take it anyway, check a lipid panel. The same studies that lowered homocysteine raised LDL and triglycerides in the same people over the same weeks.
This archive's position on supplements is simple. You take something because a number on your blood work is out of range. Then you retest, and you stop if the number does not move. That rule is awkward for this group. For most of them there is no shortage to fix, so no blood number tells you whether the bottle is doing anything. Where a compound here does move a number you can read, that number is a stand-in marker, not a shortage. Moving it is not the same as fixing something that was broken.
The evidence, in charts
Fig. 1a · how many people
170people, across 2 studies in people cited here
| Study | People | Share |
|---|---|---|
| PLoS Medicine 2005 | 151 | 89% |
| Journal of Nutrition 2003 | 19 | 11% |
One study holds 89% of these people, so the total rests more on one study than its size suggests. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. 1 more study in people gives no headcount and is not counted here. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
3 of 5 sources here are studies in people. The rest are not.
- Study in people · done in people360%
- Review of studies · sums up other studies240%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 5 different years, 2003 to 2021, counted from the list of sources on this page.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Supplement
- Molecule weight
- 117.1 Da. A quaternary ammonium amino acid derivative, not a peptide.
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
Half-life as stated on file: Betaine is cleared slowly enough that once-daily dosing raises serum levels across the day, but a precise human plasma half-life is not asserted here.
No amino acid sequence is on file for Betaine, which is expected: a supplement is not built from amino acids.
The studies we cite
- Study in people2003Low dose betaine supplementation leads to immediate and long term lowering of plasma homocysteine in healthy men and women.
Food-sized doses of betaine lowered homocysteine, steadily and at every dose tried. Four groups of 19 healthy adults took 1.5, 3 or 6 grams of betaine, or a dummy, every day for six weeks. Fasting homocysteine finished 12, 15 and 20 percent below the dummy group across the three doses. The spike that follows a methionine challenge was 23, 30 and 40 percent lower. These are amounts a person could get from ordinary eating. What this does not show is whether lowering homocysteine helps anyone.
Four groups of 19 healthy adults took 1.5, 3 or 6 grams of betaine or placebo daily for six weeks. Fasting homocysteine after six weeks was 12 percent (p < 0.01), 15 percent (p < 0.002) and 20 percent (p < 0.0001) below placebo. The rise after methionine loading was 23, 30 and 40 percent lower at six weeks. Doses inside ordinary dietary range lower homocysteine.
- Study in people2005Effect of homocysteine-lowering nutrients on blood lipids: results from four randomised, placebo-controlled studies in healthy humans.
Betaine lowers homocysteine and raises bad cholesterol at the same time. Blood fat results were pooled from four studies, three of them betaine trials covering 151 people. At 6 grams a day for six weeks, bad cholesterol rose by 0.36 units and triglycerides by 0.14. Lower doses raised bad cholesterol too, by less. The authors conclude the fat changes may cancel out any heart benefit. About 29 percent of the funding was industry money, disclosed in the paper.
Pooled blood lipid data from four placebo-controlled randomised studies, including three of betaine totalling 151 participants. Betaine at 6 g/d for six weeks raised LDL cholesterol by 0.36 mmol/L (95 percent CI 0.25 to 0.46), triacylglycerol by 0.14 mmol/L and the total to HDL ratio by 0.23, with no effect on HDL. Lower doses also raised LDL without significance, and the LDL effect was already evident at two weeks. Folic acid had no effect on lipids. The authors conclude the lipid effects may undo the potential cardiovascular benefit of homocysteine lowering. Funding was 29 percent industrial through a food science consortium, disclosed in the paper.
- Study in people2010Effects of homocysteine-lowering with folic acid plus vitamin B12 vs placebo on mortality and major morbidity in myocardial infarction survivors: a randomized trial.
The marker moved and nothing happened to the people. 12,064 heart attack survivors took folic acid and vitamin B12 daily, or a dummy, for 6.7 years, nobody knowing which. Homocysteine fell 28 percent on average. Major vascular events struck 25.5 percent of the treated group and 24.8 percent of the dummy group. A trial this size over nearly seven years would have found a real benefit. This tested B vitamins, not betaine, which is the point. It tests the idea, not the product.
12,064 myocardial infarction survivors randomised double blind to 2 mg folic acid plus 1 mg vitamin B12 daily or placebo, followed 6.7 years. Homocysteine fell by a mean 3.8 micromol/L, 28 percent. Major vascular events occurred in 1,537 of 6,033 on treatment (25.5 percent) against 1,493 of 6,031 on placebo (24.8 percent), risk ratio 1.04 (95 percent CI 0.97 to 1.12, p = 0.28). The marker moved and the outcome did not. This trial used B vitamins rather than betaine, which is the point: it tests the premise, not the product.
- Review of studies2021Betaine Supplementation Moderately Increases Total Cholesterol Levels: A Systematic Review and Meta-Analysis.
A review that pooled six studies from 2002 to 2018, all at 4 grams a day or more, for six to twenty-four weeks. Betaine raised total cholesterol a little. It had no clear pooled effect on LDL, good cholesterol or triglycerides. That is a weaker LDL signal than the 2005 pooled analysis found, and both results are worth knowing.
Six randomised placebo-controlled trials published between 2002 and 2018, all at 4 g a day or more for six to twenty-four weeks. Pooled effect on total cholesterol 0.34 mmol/L (95 percent CI 0.02 to 0.65, p = 0.0352). No significant pooled effect on LDL, HDL or triglycerides, which is a weaker LDL signal than the 2005 pooled analysis found and is worth stating alongside it.
- Review of studies2017Homocysteine-lowering interventions for preventing cardiovascular events.
A review of studies that lowered homocysteine with vitamins B6, B9 (folate) or B12. Compared with a dummy pill, they made no difference to heart attacks, deaths from any cause, or side effects. There was a small benefit for stroke. The authors concluded that more studies against a dummy pill are unlikely to change the answer.
Third update of the Cochrane review. No difference between homocysteine-lowering supplements of vitamins B6, B9 or B12 and placebo for myocardial infarction, death from any cause or adverse events; a small difference favouring treatment for stroke. Trial sequential analysis concluded that additional trials versus placebo are unlikely to increase certainty about the finding.
Common questions
Has Betaine been tested in people?
Yes. 170 people given it across 3 completed trials cited here, 1 of which found nothing. Six grams a day lowers fasting homocysteine by 20 percent in healthy adults.
What is the Betaine dosage?
No human dose established. Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose. 3 completed trials, 170 people given it
Is Betaine FDA-approved?
Betaine anhydrous is FDA-approved as a prescription medicine to treat homocystinuria, a rare inherited disease. The same molecule is also sold over the counter as a dietary supplement, usually labelled trimethylglycine or TMG. The supplement has no approved use.
Does TMG lower homocysteine?
Yes, reliably. Six grams a day lowered fasting homocysteine 20 percent more than a dummy over six weeks in healthy adults. Even 1.5 grams a day, an amount inside a normal diet, lowered it 12 percent. This is one of the most repeatable effects of any supplement on any blood marker.
So does that lower my heart attack risk?
The evidence says no. In 12,064 heart attack survivors, lowering homocysteine 28 percent did not cut heart and blood vessel events over 6.7 years. The Cochrane review found no effect on heart attacks or deaths from any cause. It said more studies with a dummy group are unlikely to change that. Those studies used B vitamins rather than betaine. But they test the idea the betaine claim depends on.
Does betaine raise cholesterol?
In the pooled results of three betaine studies, 6 grams a day raised LDL cholesterol 0.36 mmol/L and triglycerides 0.14 mmol/L. The LDL rise showed up by two weeks. A later review of six studies at 4 grams a day or more found total cholesterol up 0.34 mmol/L, but no clear pooled rise in LDL. The two reviews disagree on LDL. Both find total cholesterol goes up. If you take it, get a lipid panel.
Is betaine a prescription drug?
Betaine anhydrous is, for homocystinuria. That is an inherited disease where homocysteine builds up far above normal and causes direct harm. That approval is why betaine has a serious safety record. It is not evidence for taking TMG when your homocysteine is normal or only a bit high.
What about betaine for gym performance?
That is a separate set of studies, based on betaine helping cells hold water. The studies on this page do not cover it. Nothing in the homocysteine or cholesterol data speaks to it either way. The cholesterol finding applies no matter why you take it.
Is there any anti-ageing evidence?
None. No study has measured lifespan, healthy ageing or any ageing result with betaine. It shows up in longevity stacks because of its role in methylation, a basic chemical tagging process in the body. That is a mechanism, not a result.