Water-soluble vitamins
Vitamin B9 (Folate)
DNA synthesis
One-carbon metabolism; DNA synthesis, methylation, red blood cell formation.
Upper-limit caution
The Tolerable Upper Intake Level for Vitamin B9 (Folate) is 1000 mcg per day. Routine intakes above this level — counting food + supplements — raise the risk of adverse effects. Multivitamins, fortified foods, and standalone supplements stack faster than people expect.
Forms to avoid
Not all Vitamin B9 (Folate) forms absorb equally well. The following forms are commonly used because they're cheap, but their bioavailability is materially lower than alternatives — watch for them on supplement labels:
- folic acid
Formulate's product scoring penalizes these forms when they appear as the primary Vitamin B9 (Folate) source — see the methodology page for the rubric.
How Vitamin B9 (Folate) appears on labels
Supplement labels list Vitamin B9 (Folate) under several names depending on the chemical form used. Any of these on an ingredients panel counts toward your Vitamin B9 (Folate) intake:
- folate
- folic acid
- vitamin b9
- vitamin b-9
- methylfolate
- 5-mthf
- l-methylfolate
- folinic acid
Deep dive
For mechanism of action, dosing protocols, evidence grade, and interaction warnings on Vitamin B9 (Folate), see the full encyclopedia entry:
Folate encyclopedia entry →Related water-soluble vitamins
Track your full intake
Formulate's free desktop app aggregates Vitamin B9 (Folate) (and ~40 other nutrients) across every supplement in your stack — flagging underdoses, overlaps, and upper-limit overshoots in one view.
Get the appMedical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Targets and upper limits are general adult reference values; individual needs vary by age, sex, pregnancy status, and clinical context.