Know2eat

Methylfolate (5-MTHF)

Vitamins

What methylfolate (5-mthf) may help with

Ranked by how strong the human evidence is — best supported first.

Best supportedPregnancy nutritionModerate evidence· 2 sources

Then, in order

About Methylfolate (5-MTHF)

The form of folate that actually circulates in blood, sold as a calcium or glucosamine salt. It bypasses the enzymatic conversion steps needed to activate folic acid, which is the basis of its marketing to people with MTHFR gene variants.

Methylfolate is a legitimate folate source with a marketing story that outruns its data. It raises blood folate at least as effectively as folic acid, and it avoids the unmetabolised folic acid that appears at high intakes. What has not been demonstrated is that it is clinically better for anyone — including people carrying MTHFR C677T variants, who make up a large share of the population and who achieve normal folate status on ordinary folic acid. Crucially, the enormous neural tube defect evidence base was built on folic acid, not methylfolate, and no equivalent trial exists for the active form. For anyone planning a pregnancy that is the decisive consideration, whatever a genetic test report suggests.

Sold as
Capsule, Tablet, Sublingual tablet, Component of "methylated" B-complex, Prescription medical food
Standardised to
Sold as calcium L-5-methyltetrahydrofolate or the glucosamine salt; only the L-isomer is active — a product without this marker may not resemble what was studied.
Also known as
5-methyltetrahydrofolate, L-methylfolate, Metafolin, Quatrefolic, Active folate

Regulation: The 1,000 µg/day upper limit for folic acid was set on masking of B12 deficiency; methylfolate is generally assumed to carry the same masking risk, though it was not the basis for the limit. Prescription-strength L-methylfolate is marketed in the US as a medical food for depression adjunctive use.

What the research used

The amounts, forms and durations published trials of Methylfolate (5-MTHF) actually administered.

These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.

  • Studied for Typical retail supplement

    400–1000 µg

    Moderate

    Capsule or tablet, daily

    Broadly matched to folic acid doses. Bioavailability studies find it raises blood folate comparably or slightly better; no outcome trial has compared the two forms.

  • Studied for Adjunctive use in depression

    7.5–15 mg

    Limited

    L-methylfolate, daily alongside an antidepressant · 8–12 weeks

    From trials in people with inadequate antidepressant response, several with manufacturer involvement. This is 15–35 times the RDA and sold in the US under the medical food category.

This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.

When it was taken

Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.

None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.

  • Any time

    Not enough

    No timing effect has been established. Some people report that methylfolate feels stimulating and prefer mornings, which is anecdote rather than data.

    Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.

The evidence in depth

Best supported: Moderate

What each association actually rests on, and the papers behind it. A rating describes the state of the research, not how promising the supplement sounds. How we rate evidence.

Pregnancy nutrition

Women's Health
Moderate evidence

Methylfolate raises blood folate effectively and is a reasonable folate source. But the trials that established folate's role in reducing neural tube defects used folic acid, and no equivalent evidence exists for methylfolate — which is why obstetric guidance still specifies folic acid, including for women with MTHFR variants.

Moderate evidence. Several human studies point the same way, with real caveats.

View the 2 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Mood

Mental Wellbeing
Limited evidence

Trials of high-dose L-methylfolate added to antidepressants report modest improvement in response rates, mainly in people with obesity or inflammatory markers. The trials are few, funded by the manufacturer, and have not been independently replicated at scale.

Limited evidence. Early human work, or mostly lab and animal research.

View the 3 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Cardiovascular risk markers

Heart Health
Not enough evidence

Methylfolate lowers homocysteine like folic acid. The large trials showed that lowering homocysteine does not reduce cardiovascular events, and there is no reason to expect a different result from a different folate form.

Not enough evidence. Not enough human research to say anything useful yet.

View the 2 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Things to know

Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.

  • Worth knowing

    Masks B12 deficiency in the same way as folic acid

    Any folate form can correct the anaemia of B12 deficiency while neurological damage continues. Checking B12 status matters before long-term high-dose folate of any kind, especially in older adults, vegans, and people taking metformin or long-term acid suppression.

  • Worth knowing

    MTHFR testing is oversold

    C677T and A1298C variants are common, and major genetics and obstetric bodies do not recommend routine testing for them or a change in folate form on their basis. Direct-to-consumer reports that recommend methylfolate on a variant alone are running ahead of the professional guidance.

  • Interaction

    Same drug interactions as folic acid

    Interacts withMethotrexate, phenytoin, phenobarbital, primidone, sulfasalazine

    Interactions with methotrexate, phenytoin, phenobarbital, primidone and sulfasalazine apply to all folate forms.

  • Worth knowing

    Cost and isomer quality

    Methylfolate typically costs several times more than folic acid. Only the L-isomer is biologically active, and some cheaper products historically contained racemic mixtures, so the salt form on the label is worth checking.

Evidence ratings on this page: 1 moderate evidence, 1 limited evidence, 1 not enough evidence.

Supplements are sold in the US without pre-market review of efficacy or safety. Nothing on this page is a recommendation to take Methylfolate (5-MTHF), or a dose to follow.