Supplements for methylation: TMG, B12, folate, B6, choline, and SAMe compared
Short answer: the supplements that have been most thoroughly researched within the methylation cycle are folate (folic acid or methylfolate), vitamin B12 and TMG (betaine). All three assist in the conversion of homocysteine to methionine, each via its own pathway. In randomized trials, 0.8 mg of folic acid per day lowered homocysteine by approximately one quarter, vitamin B12 added about 7% to that, and 1.5 to 6 grams of betaine per day resulted in a decrease of approximately 12 to 20%. Choline works via betaine and lowered homocysteine in a study using high doses. Vitamin B6 and riboflavin (B2) are cofactors but have little effect on their own, except for riboflavin in individuals with a specific MTHFR variant. SAMe is the most important methyl donor in the body, but as a supplement, it is researched for mood and joints, not for lowering homocysteine.
This article is for informational purposes and does not replace medical advice. Every Day Better sells TMG; therefore, we also discuss alternatives that we do not sell.
What is methylation?
Methylation is the transfer of a methyl group (one carbon atom with three hydrogen atoms) from one molecule to another. The body uses these reactions for, among other things, gene regulation, the production of neurotransmitters and creatine, and the breakdown of substances in the liver. The primary methyl donor is S-adenosylmethionine (SAMe). After SAMe has donated its methyl group, homocysteine is formed via an intermediate step.
Homocysteine must then be converted back. This can happen in three ways:
- Folate + vitamin B12 (methionine synthase pathway): homocysteine is converted back into methionine. This pathway works in almost all cells.
- Betaine/TMG (BHMT pathway): betaine directly provides a methyl group to homocysteine, primarily in the liver and kidneys. Choline is partially converted into betaine in the body.
- Vitamin B6 (transsulfuration): homocysteine is broken down into cysteine, a building block for glutathione, among other things.
In practice, elevated homocysteine is the most commonly used measurable indication that this cycle is not functioning optimally. A simple, validated test for “methylation” as a whole does not exist; you can have homocysteine measured through your GP or a lab.
Methylation supplements compared
| Supplement | Pathway | Effect on homocysteine in humans | Key consideration |
|---|---|---|---|
| Folate (folic acid or methylfolate) | Methionine synthase | Strong: approximately 23% reduction with 0.8 mg folic acid per day in a meta-analysis of randomized trials | Effect is greatest with low folate status; high doses of folic acid can mask a B12 deficiency |
| Vitamin B12 | Methionine synthase (cofactor) | Approximately 7% additional reduction on top of folate | Particularly relevant for low B12 status, for example in the elderly, vegans, and users of metformin or antacids |
| TMG (betaine) | BHMT | Approximately 12–20% reduction at 1.5–6 g per day | Above 4 g per day, LDL cholesterol may increase; works independently of folate and B12 |
| Choline | Via conversion to betaine | Approximately 18% reduction with circa 2.6 g choline per day (as phosphatidylcholine) in a small study | High doses; can cause fishy odor and gastrointestinal complaints |
| Vitamin B6 | Transsulfuration | Little effect on fasting homocysteine as a standalone supplement | Long-term high doses can cause nerve issues |
| Riboflavin (B2) | Cofactor of the MTHFR enzyme | Reduction only seen in individuals with the MTHFR 677TT genotype | No measurable effect in other genotypes |
| SAMe | Is the methyl donor itself | Not researched or used to lower homocysteine | Researched for mood and osteoarthritis; use caution with antidepressants and bipolar disorder |
Folate and vitamin B12: the best-supported foundation
A meta-analysis of randomized trials by the Homocysteine Lowering Trialists’ Collaboration (2005) showed that 0.8 mg of folic acid per day lowers homocysteine by approximately 23%; lower doses produced a smaller effect. Vitamin B12 provided an additional reduction of about 7%. In the EU, folate, vitamin B12, and vitamin B6 are permitted to state that they contribute to normal homocysteine metabolism.
Folic acid or methylfolate? Methylfolate (5-MTHF) is the form the body uses directly and does not need to be converted by the MTHFR enzyme first. Both forms lower homocysteine in studies. For people with an MTHFR variant, methylfolate is often chosen, but folic acid has also been shown to be effective for them.
TMG (betaine): a second, independent pathway
TMG stands for trimethylglycine and is the same as betaine. It provides a methyl group to homocysteine via the BHMT enzyme. In a randomized trial, 1.5, 3, and 6 grams of betaine per day for six weeks lowered fasting homocysteine by 12, 15, and 20% respectively compared to placebo (Olthof et al., 2003). The European health claim applies at 1.5 grams per day, with the warning that more than 4 grams per day can increase cholesterol.
Because TMG works via a different pathway than folate and B12, it is particularly interesting as a supplement. A study from 2026 investigated betaine on top of B vitamins for elevated homocysteine; read the discussion in betaine on top of B vitamins. You can read more about its function and dosage in what is TMG? and TMG dosage.
Choline: indirect via betaine
Choline is found in eggs, meat, fish, and soy, among other things. The body converts part of it into betaine. In a small randomized trial in healthy men, approximately 2.6 grams of choline per day (as phosphatidylcholine) lowered fasting homocysteine by about 18% (Olthof et al., 2003). This is a high dose. Choline also has an EU claim for normal homocysteine metabolism.
Vitamin B6 and riboflavin: cofactors with limited standalone effect
Vitamin B6 is required for the breakdown of homocysteine into cysteine, but as a standalone supplement, it hardly lowers fasting homocysteine. Long-term high doses of B6 can cause nerve issues (neuropathy), so more is not better here.
Riboflavin (vitamin B2) is a cofactor of MTHFR. In a randomized trial, homocysteine decreased after 1.6 mg of riboflavin per day only in participants with the MTHFR 677TT genotype, not in others (McNulty et al., 2006).
SAMe: the methyl donor itself, but with a different purpose
SAMe is the substance the body uses for most methylation reactions. As a supplement, SAMe has primarily been researched for depressive symptoms and osteoarthritis of the knee, with mixed results. It is not used to lower homocysteine: after donating its methyl group, SAMe is actually converted toward homocysteine. Do not combine SAMe with antidepressants without consultation, and be cautious with bipolar disorder.
How to choose?
- Get tested first. A homocysteine, folate, and B12 measurement says more than a general “methylation stack”.
- Start with the basics. If folate or B12 status is low, targeted supplementation is the most logical step.
- TMG as an addition. TMG works via its own pathway and is particularly relevant if you want to support your homocysteine metabolism more broadly, or if you combine NMN with TMG.
- Watch the dose. More is not automatically better: high doses of B6, folic acid, and betaine each have their own considerations.
- Consult regarding medication. Especially with metformin, antacids, anti-epileptics, methotrexate, or antidepressants.
Want to know how methylation supplements compare to other longevity supplements? View the best longevity supplements in 2026, ranked by evidence.
Frequently asked questions about methylation supplements
Which supplement is best for methylation?
There is no single best supplement. Folate and vitamin B12 are the best-supported for normal homocysteine metabolism, especially when status is low. TMG (betaine) works via a second pathway and also demonstrably lowers homocysteine.
Is TMG better than methylfolate?
They do not do the same thing. Methylfolate works with B12 via methionine synthase, while TMG works via the BHMT enzyme. In studies, folic acid produces a larger effect on homocysteine per dose than betaine, but the two can complement each other.
Can you combine TMG and methylfolate?
Yes, that is possible because they work via different pathways, and in studies, betaine has also been researched on top of B vitamins. Preferably, have your homocysteine and B-vitamin status measured first and consult if you are using medication.
What does SAMe do for methylation?
SAMe is the methyl donor that the body uses itself. As a supplement, it has primarily been researched for mood and osteoarthritis, not for lowering homocysteine.
How do I know if my methylation is working properly?
There is no simple test for methylation as a whole. Homocysteine, folate, and vitamin B12 in the blood are the most commonly used measurable indications; discuss the results with your GP.
Sources
- Homocysteine Lowering Trialists’ Collaboration (2005). Dose-dependent effects of folic acid on blood concentrations of homocysteine: a meta-analysis of the randomized trials. Am J Clin Nutr.
- Olthof et al. (2003). Low dose betaine supplementation leads to immediate and long term lowering of plasma homocysteine in healthy men and women. J Nutr.
- Olthof et al. (2003). Choline supplemented as phosphatidylcholine decreases fasting and postmethionine-loading plasma homocysteine concentrations in healthy men. Am J Clin Nutr.
- McNulty et al. (2006). Riboflavin lowers homocysteine in individuals homozygous for the MTHFR 677C->T polymorphism. Circulation.
- Zawieja et al. (2021). Betaine supplementation moderately increases total cholesterol levels: a systematic review and meta-analysis. J Diet Suppl.
- Regulation (EU) No 432/2012: permitted health claims.
Last updated: October 22, 2026. Written by Every Day Better.
