Vitamin B9
Vitamin ·Exploratory record · not publication-reviewed ·Updated July 13, 2026
Essential for DNA synthesis, cell division, and methylation. Critical during pregnancy for neural tube development. Methylfolate is the bioactive form.
Exploratory record, not a reviewed medical publication.
See the editorial and medical-review policies for the publication gate.
This generated database record has not completed a claim-level review by a qualified human medical reviewer. Bibliography links and evidence labels are not approval. The page remains available for reference and is excluded from search indexing.
What the research says.
A quick, data-only summary. The full evidence, dosing, and sources are below.
Vitamin B9 is a vitamin most often used for dna synthesis, cell division, neural tube development. NutriStack rates the overall evidence as strong. A typical adult dose is 400–1,000 mcg daily, commonly taken as methylfolate (5-mthf), avoids mthfr gene variant issues. This profile indexes 18 sources.
The bottom line
Evidence rating strong. Most-documented uses: dna synthesis, cell division, neural tube development. 18 sources indexed (2006–2025), with 0 interaction records on file.
How it works, mechanistically.
Core mechanism
As tetrahydrofolate (THF), serves as a one-carbon carrier in nucleotide synthesis (DNA/RNA), amino acid metabolism, and the methylation cycle. 5-MTHF donates a methyl group to homocysteine via methionine synthase (requires B12) to produce methionine and SAMe.13
Dosing & protocol.
What it actually costs.
Real-world pricing across three quality tiers. Assumes Folic Acid.
Assumes 400-800 mcg/day. Folic acid is extremely inexpensive, but it is not always the best value if methylfolate is clinically preferred. Updated 2026-04-02.
The same dose, as food.
How much you'd eat to match a supplemental dose.
Food folate is meaningful, but prenatal-style intake targets are easier with supplements.
Supplement use is common in preconception and pregnancy for this reason.
Full safety detail.
Side effects
- May mask B12 deficiency
- Rare GI upset
Contraindications
- May mask B12 deficiency symptoms14
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Meta-analyses & systematic reviews
11- 1Folic Acid Supplementation and Risk of Gestational Diabetes Mellitus: A Systematic Review of the LiteraturePMIDGómez-Cabrera AS, González-Santiago AE, Castañeda-Arellano R et al. · International journal of molecular sciences · 2025
Gómez-Cabrera AS, González-Santiago AE, Castañeda-Arellano R et al.. Folic Acid Supplementation and Risk of Gestational Diabetes Mellitus: A Systematic Review of the Literature. International journal of molecular sciences. 2025
- 2Folate Supplementation for Peripheral Neuropathy: A Systematic ReviewPMIDAlves Maues AC, Moren Abat MG, Benlloch M et al. · Nutrients · 2025
Alves Maues AC, Moren Abat MG, Benlloch M et al.. Folate Supplementation for Peripheral Neuropathy: A Systematic Review. Nutrients. 2025
- 3Folic acid supplementation for stroke prevention: A systematic review and meta-analysis of 21 randomized clinical trials worldwidePMIDZhang N, Zhou Z, Chi X et al. · Clinical nutrition (Edinburgh, Scotland) · 2024
Zhang N, Zhou Z, Chi X et al.. Folic acid supplementation for stroke prevention: A systematic review and meta-analysis of 21 randomized clinical trials worldwide. Clinical nutrition (Edinburgh, Scotland). 2024
- 4The Efficacy and Safety of Folate Receptor α-Targeted Antibody-Drug Conjugate Therapy in Patients With High-Grade Epithelial Ovarian, Primary Peritoneal, or Fallopian Tube Cancers: A Systematic Review and Meta-AnalysisPMIDKim ET, Kim JH, Park EY et al. · Cancer medicine · 2024
Kim ET, Kim JH, Park EY et al.. The Efficacy and Safety of Folate Receptor α-Targeted Antibody-Drug Conjugate Therapy in Patients With High-Grade Epithelial Ovarian, Primary Peritoneal, or Fallopian Tube Cancers: A Systematic Review and Meta-Analysis. Cancer medicine. 2024
- 5Folic Acid in the Treatment of Sickle Cell Disease: A Systematic ReviewPMIDArrey Agbor DB, Panday P, Ejaz S et al. · Cureus · 2024
Arrey Agbor DB, Panday P, Ejaz S et al.. Folic Acid in the Treatment of Sickle Cell Disease: A Systematic Review. Cureus. 2024
- 6Maternal folic acid supplementation to prevent preeclampsia: a systematic review and meta-analysisPMIDCui H, Zhang N, An J et al. · Complementary therapies in medicine · 2024
Cui H, Zhang N, An J et al.. Maternal folic acid supplementation to prevent preeclampsia: a systematic review and meta-analysis. Complementary therapies in medicine. 2024
- 7Folic Acid Supplementation to Prevent Neural Tube Defects: Updated Evidence Report and Systematic Review for the US Preventive Services Task ForcePMIDViswanathan M et al. · JAMA · 2023
New evidence from observational studies provides additional evidence of benefit of folic acid supplementation for preventing NTDs and no evidence of harms related to multiple gestation, autism, or maternal cancer
- 8Folate as adjunct therapy to SSRI/SNRI for major depressive disorder: Systematic review & meta-analysisPMIDAltaf R, Gonzalez I, Rubino K, Nemec EC 2nd · Complementary Therapies in Medicine · 2021
In 6 RCTs, adjunct folate therapy significantly improved HAM-D scores (MD -2.16, p=0.004), improved response rate (RR 1.36, p=0.0001), and increased remission rate (RR 1.39, p=0.05) compared to SSRI/SNRI monotherapy.
- 9Folic acid supplementation and the risk of cardiovascular diseases: a meta-analysis of randomized controlled trialsSource linkedPMIDLi Y, Huang T, Zhuo Y et al. · Clin Nutr · 2016
- 10Folic acid supplementation and the prevention of neural tube defects: a systematic reviewSource linkedPMIDDe-Regil LM, Pena-Rosas JP, Fernandez-Gaxiola AC, Rayco-Solon P · Cochrane Database Syst Rev · 2015
- 11Homocysteine and coronary heart disease: meta-analysis of MTHFR case-control studies, avoiding publication biasPMIDClarke R et al. · PLoS Med · 2012
MTHFR TT genotype associated with modest cardiovascular risk increase mediated mainly by increased homocysteine and low plasma folate
Randomized controlled trials
1- 12Homocysteine lowering with folic acid and B vitamins in vascular diseaseSource linkedPMIDHOPE-2 Investigators · N Engl J Med · 2006
Reviews & position papers
4- 13Supplementation with Folic Acid or 5-Methyltetrahydrofolate and Prevention of Neural Tube Defects: An Evidence-Based Narrative ReviewPMIDVarious · Nutrients · 2024
Carriers of certain MTHFR polymorphisms may benefit more from 5-methylTHF than folic acid; 5-MTHF is a better alternative, especially in countries without fortification
- 14Excess Folic Acid and Vitamin B12 Deficiency: Clinical Implications?PMIDVarious · Clin Chem Lab Med · 2024
High serum folate during vitamin B12 deficiency may exacerbate anemia and worsen cognitive symptoms rather than simply 'masking' the deficiency
- 15Folic Acid Supplementation to Prevent Neural Tube Defects: US Preventive Services Task Force Reaffirmation Recommendation StatementPMIDUS Preventive Services Task Force · JAMA · 2023
USPSTF recommends all persons planning/could become pregnant take daily supplement of 0.4-0.8 mg folic acid (Grade A recommendation)
- 16Folic acid and primary prevention of neural tube defects: A reviewPMIDImbard A et al. · Ann Biol Clin · 2013
In a Hungarian RCT, NTD incidence was 0% with folic acid vs 0.25% with trace element supplementation; established strong evidence for NTD prevention
Reference material
2- 17Maruf AA, Poweleit EA, Brown LC et al.. Systematic Review and Meta-Analysis of L-Methylfolate Augmentation in Depressive Disorders. Pharmacopsychiatry. 2022Source linkedPMID
- 18Hoxha B, Hoxha M, Domi E et al.. Folic Acid and Autism: A Systematic Review of the Current State of Knowledge. Cells. 2021Source linkedPMID
Common questions.
Quick answers about Vitamin B9, drawn from the data on this page.
What is Vitamin B9?
Essential for DNA synthesis, cell division, and methylation. Critical during pregnancy for neural tube development. Methylfolate is the bioactive form.
What is Vitamin B9 used for?
Commonly cited benefits of Vitamin B9 include: DNA synthesis; Cell division; Neural tube development; Methylation support; Homocysteine reduction. NutriStack rates the overall evidence as strong.
What is a typical dose of Vitamin B9?
A typical adult dose of Vitamin B9 is 400–1,000 mcg daily. The commonly recommended form is Methylfolate (5-MTHF), avoids MTHFR gene variant issues. These are general ranges, not personalized advice; confirm the right dose with a clinician.
What are the side effects of Vitamin B9?
Reported side effects include may mask b12 deficiency, rare gi upset. This is educational information; check with a healthcare professional before use.
How strong is the evidence for Vitamin B9?
NutriStack rates this as Strong, meaning multiple high-quality meta-analyses or systematic reviews converge on the same finding. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.
Use this with your stack
Vitamin B9 in NutriStack.
Add it to your stack, see how it interacts with everything else you take, and get a Stack Score that updates the moment it does.