Check before you startThis one has documented interactions with medication classes where the consequences are serious. If you take any prescription medicine, run it past a pharmacist before starting.
How long to take it
Course-based outside pregnancy.
Who it's actually for
Pregnancy planning, malabsorption, and certain medications.
Safe upper limit
Verified1,000 mcg per day of supplemental folic acid
The limit exists specifically because folate hides B12 deficiency while nerve damage progresses.
The 1,000 mcg/day figure traces to a 2000 SCF evaluation, carried forward in EFSA's re-assessment.
Interactions to know about
- Methotrexate — Folate antagonist
- Anti-seizure medication — Phenytoin, valproate, carbamazepine, lamotrigine
Other supplements:
Run your full list through the interaction check.
Practical notes
- Always check B12 alongside folate.
- Methotrexate users need medical guidance on timing.