Folate (Vitamin B9)
- Effective dose
- 400–800 mcg
- Evidence
- 5/5· Robust
Last updated June 1, 2026
What it is
Folate (vitamin B9) is a water-soluble vitamin essential for DNA synthesis and for converting homocysteine to methionine. Folic acid is the synthetic form used in supplements and fortified foods.
Benefits
Folate is firmly established to prevent neural tube defects: 400–800 mcg/day of folic acid starting at least one month before conception and through early pregnancy substantially reduces risk.
When to take it
Taken daily at any time, with or without food; consistency matters more than timing because the benefit depends on adequate stores.
Side effects
Folate from food is safe; the upper limit for synthetic folic acid is 1,000 mcg/day for adults. High folic acid intake can mask the anemia of vitamin B12 deficiency, allowing nerve damage to progress undetected.
Sources
Products containing Folate (Vitamin B9)
No products in our database contain this ingredient yet.