Is Methotrexate Safe with L-Methylfolate?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Do not take L-Methylfolate while on methotrexate therapy without explicit approval from your rheumatologist or oncologist. The timing and dose of folate supplementation must be carefully managed.
Why this interaction occurs
Methotrexate works by inhibiting dihydrofolate reductase, depleting folate-dependent pathways. Supplementing with L-Methylfolate (the active folate form) may antagonize methotrexate's therapeutic mechanism, particularly in oncology or autoimmune indications, reducing its clinical effectiveness.
Evidence
Evidence level: strong.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 35,992 reports mentioning L-Methylfolate. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the L-Methylfolate + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All Methotrexate interactions → · All L-Methylfolate interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.