Can I take folic acid and methylfolate together? An expert guide

January 2, 2026 •

3 min read

Approximately 40–60% of the population has a common genetic variation affecting their ability to convert folic acid into its active form, methylfolate. This raises an important question: Can I take folic acid and methylfolate together? While both are forms of vitamin B9, their combined use is generally not recommended and requires a careful understanding of the metabolic pathways involved.

Quick Summary

Combining folic acid and methylfolate supplements is not recommended due to potential risks, including masking a vitamin B12 deficiency. A doctor should guide your choice.

Key Points

Combination Not Recommended: Combining folic acid and methylfolate is generally not advised due to potential risks.
Risk of B12 Masking: High folic acid can hide a vitamin B12 deficiency, risking irreversible nerve damage.
MTHFR Gene Variation: This mutation can make converting folic acid less efficient; methylfolate bypasses this issue.
Choose One Form: Select one form of folate based on health needs and doctor's advice.
Consult a Doctor: Always seek professional medical guidance before starting or changing folate supplements.
Unmetabolized Folic Acid (UMFA): Excess folic acid can build up as UMFA, potentially affecting health.

Understanding the different forms of Vitamin B9

Vitamin B9 exists in several forms, including folic acid and methylfolate. Folic acid is a synthetic version used in fortified foods and supplements. Methylfolate, also known as 5-methyltetrahydrofolate (5-MTHF), is the natural, active form the body utilizes.

How your body uses folate

The body must convert folic acid into methylfolate using the MTHFR enzyme. A common MTHFR gene variation can make this conversion less efficient for some individuals. Methylfolate, being active, bypasses this conversion.

The risks of combining folic acid and methylfolate

Combining folic acid and methylfolate is not generally advised, despite no known drug interaction. While the body typically excretes excess water-soluble vitamins, high doses, especially of folic acid, carry risks.

The danger of masking a vitamin B12 deficiency

A significant risk is that excess folic acid can mask a vitamin B12 deficiency. Both deficiencies can cause megaloblastic anemia. Folic acid can correct the anemia caused by B12 deficiency, delaying diagnosis of the B12 issue. Untreated B12 deficiency can cause irreversible nerve damage and cognitive problems.

Potential for unmetabolized folic acid (UMFA)

When more folic acid is consumed than the body can convert, it can build up as unmetabolized folic acid (UMFA) in the bloodstream. Research links high UMFA levels to potential negative effects on immune and brain function. Methylfolate does not require conversion, thus preventing UMFA buildup.

Confusion and improper dosing

Taking both supplements can lead to confusion regarding proper dosage. Consulting a healthcare provider is essential to determine the right form and dose based on individual health, genetics, and needs, such as during pregnancy.

Comparison: Folic Acid vs. Methylfolate


Feature	Folic Acid	Methylfolate (5-MTHF)
Source	Synthetic (lab-made), found in fortified foods and supplements.	Naturally occurring in some foods and supplements; body's active form.
Conversion Needed	Requires conversion by the MTHFR enzyme to become active.	Is already in the active form, no conversion needed.
Bioavailability	High absorption rate, but efficiency depends on MTHFR function.	High bioavailability, ready for direct use by all individuals.
MTHFR Relevance	Less efficient for individuals with MTHFR genetic mutations.	Bypasses MTHFR pathway, making it ideal for those with gene variations.
Cost	Generally more affordable than methylfolate supplements.	Can be more expensive due to higher processing costs.
Risk Profile	High intake can mask B12 deficiency and lead to UMFA build-up.	Does not pose the same risk of masking B12 deficiency and avoids UMFA.

Who should consider methylfolate?

Methylfolate may be a better option for certain individuals:

Individuals with MTHFR Mutations: Those with this genetic variation may have reduced conversion of folic acid. Methylfolate provides the active form directly.
Patients with High Homocysteine: Elevated homocysteine is a cardiovascular risk. Methylfolate's high bioavailability may help manage these levels.
Certain Mental Health Conditions: Methylfolate may be beneficial as an adjunctive treatment for some types of depression, potentially linked to folate metabolism issues.

How to decide on the right supplementation strategy

Choosing a folate supplement requires professional medical advice. Discuss your health history, genetics, and goals with your doctor. They can advise on MTHFR testing and recommend the best form and dose, while monitoring B12 levels. The CDC notes that while most with MTHFR variants can process folic acid, there's not yet conclusive evidence to universally recommend methylfolate.

For more information on folic acid, consult the National Institutes of Health factsheet.

Conclusion

In conclusion, taking folic acid and methylfolate together is generally not recommended due to risks like masking B12 deficiency and UMFA accumulation. The best choice depends on individual metabolism, particularly MTHFR status. Always consult a healthcare professional for personalized guidance on folate supplementation.

Frequently Asked Questions

Yes, taking both is not recommended. The main risk is that high levels of folic acid can mask a vitamin B12 deficiency, potentially leading to irreversible nerve damage. It can also lead to an unnecessary buildup of unconverted folic acid in the bloodstream.

Folic acid is the synthetic form of vitamin B9 that needs to be converted by the body into its active form. Methylfolate is the active, natural form of vitamin B9 that the body can use directly.

An MTHFR gene mutation can impair the body’s ability to convert folic acid into its active form. Methylfolate is already in the active form, so it bypasses this metabolic block and ensures the body gets enough usable folate.

Yes. High doses of folic acid can correct the megaloblastic anemia caused by a B12 deficiency, allowing the deficiency to go undetected while irreversible nerve damage progresses.

If you have an MTHFR gene variant, your body may not convert folic acid to methylfolate as efficiently. While some conversion still happens, it may not be enough for optimal folate levels, especially if your intake is not high. However, the CDC states that most people with the variant still benefit from standard folic acid.

While natural folate from food is safe, excessive intake of synthetic folic acid can lead to side effects. These can include stomach issues, irritability, sleep problems, and a heightened risk of masking a B12 deficiency.

A healthcare provider can order a genetic test to check for common MTHFR variations. This is often done with a simple blood test. It's important to discuss the implications of such a test with your doctor.