{"ok":true,"entry":{"slug":"l-methylfolate","kind":"supplement","name":"L-methylfolate","aliases":["5-MTHF","methylfolate","L-5-methyltetrahydrofolate"],"brands_sg":["California Gold Nutrition","Jarrow Formulas","NOW Foods","Doctor's Best","Life Extension"],"class":"folate form","tags":["womens-health","general"],"use_for":"dna and amino-acid work · folate's main form in plasma","use_after":"no timing rule","use_duration":null,"take_with":"with adequate b12 · high folate can mask a b12 deficiency","pros":["bioavailability equals or beats folic acid","some with the mthfr 677c>t variant may benefit","15,000 mcg/day as an ssri add-on — low-quality evidence"],"cons":["cdc advises folic acid, not 5-mthf, before pregnancy","no formal mcg to mcg dfe conversion factor exists","high folate can mask a b12 deficiency"],"dose_note":"the folate rda is 400 mcg dfe a day for adults, 600 mcg dfe in pregnancy and 500 mcg dfe when breastfeeding, and the fda daily value is 400 mcg dfe; the ul of 1,000 mcg applies to the synthetic folate in supplements and fortified foods, not to food folate, and does not apply to people taking high doses under medical supervision; conversion factors between mcg and mcg dfe for 5-mthf have not been formally established, so label maths differ between products; hsa's singapore limit for health supplements is 0.9 mg (900 mcg) a day and both the annex row and the vitamins table name folic acid, not 5-mthf; in depression research 5-mthf has been studied at 7,500–15,000 mcg/day alongside ssris, and the pooled conclusion that 15,000 mcg/day might be an effective adjunct was rated low-quality evidence","dosage":{"ul":1000,"unit":"mcg","fda_dv":"400 mcg DFE","rda_ai":"400 mcg DFE (19+) · 600 mcg DFE pregnancy · 500 mcg DFE lactation","ul_status":"established","population":"general adult","hsa_max_daily":"0.9 mg — HSA's row names folic acid, not 5-MTHF"},"ul_status":"established","sg_class":null,"cautions":["pregnant or planning — cdc advises 400 mcg/day folic acid, not 5-mthf","low b12 or unexplained anaemia — folate can correct the anaemia, not the nerve damage","on methotrexate for cancer — it is a folate antagonist; the oncologist decides","on an antiepileptic — folate supplements might lower those drug levels"],"clashes":[{"src":["nih_ods_folate_interactions"],"note":"a folate antagonist; supplements could interfere with its anticancer effects, though they might ease gi side effects of low-dose use","with":"methotrexate"},{"src":["nih_ods_folate_interactions"],"note":"these lower serum folate, and folate supplements might in turn lower serum levels of the drugs","with":"antiepileptics (phenytoin, carbamazepine, valproate)"},{"src":["nih_ods_folate_interactions"],"note":"inhibits intestinal folate absorption and can cause folate deficiency","with":"sulfasalazine"}],"sources":[{"id":"nih_ods_folate_forms","url":"https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/","label":"NIH ODS — Folate (Health Professional), updated November 30, 2022 — Introduction (read via archive.org capture, see verify_notes)","quote":"Some dietary supplements also contain folate in the monoglutamyl form, 5-MTHF (also known as L-5-MTHF, 5-methyl-folate, L-methylfolate, and methylfolate) … The main form of folate in plasma is 5-MTHF","accessed":"2026-08-27"},{"id":"nih_ods_folate_function","url":"https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/","label":"NIH ODS — Folate (Health Professional) — Introduction, function","quote":"Folate functions as a coenzyme … in single-carbon transfers in the synthesis of nucleic acids (DNA and RNA) and metabolism of amino acids","accessed":"2026-08-27"},{"id":"nih_ods_folate_bioavail","url":"https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/","label":"NIH ODS — Folate (Health Professional) — Sources of Folate, dietary supplements","quote":"The bioavailability of 5-MTHF in supplements is the same as or greater than that of folic acid … However, conversion factors between mcg and mcg DFE for 5-MTHF have not been formally established","accessed":"2026-08-27"},{"id":"nih_ods_folate_mthfr","url":"https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/","label":"NIH ODS — Folate (Health Professional) — Groups at Risk, MTHFR 677C>T polymorphism","quote":"some of these people might benefit from supplementation with 5-MTHF. However, the Centers for Disease Control and Prevention (CDC) recommends 400 mcg/day of folic acid, not 5-MTHF, for people who could become pregnant","accessed":"2026-08-27"},{"id":"nih_ods_folate_rda","url":"https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/","label":"NIH ODS — Folate (Health Professional) — Table 1 RDAs and the DV note","quote":"19+ years 400 mcg DFE 400 mcg DFE 600 mcg DFE 500 mcg DFE … The DV for folate is 400 mcg DFE for adults and children age 4 years and older","accessed":"2026-08-27"},{"id":"nih_ods_folate_ul","url":"https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/","label":"NIH ODS — Folate (Health Professional) — Health Risks from Excessive Folate; Table 3 ULs","quote":"the FNB established a UL for the synthetic forms of folate available in dietary supplements and fortified foods … 19+ years 1,000 mcg … The ULs do not apply to individuals taking high doses of supplemental folate under medical supervision","accessed":"2026-08-27"},{"id":"nih_ods_folate_b12","url":"https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/","label":"NIH ODS — Folate (Health Professional) — Health Risks, masking of vitamin B12 deficiency","quote":"Large amounts of folate can correct the megaloblastic anemia, but not the neurological damage, that can result from vitamin B12 deficiency … high intakes of folate supplements might mask vitamin B12 deficiency","accessed":"2026-08-27"},{"id":"nih_ods_folate_depression","url":"https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/","label":"NIH ODS — Folate (Health Professional) — Folate and Health, depression","quote":"a systematic review and meta-analysis of three trials of 5-MTHF … concluded that 15,000 mcg/day 5-MTHF might be an effective adjunct to SSRI therapy in patients with major depressive disorder, although … this conclusion was based on low-quality evidence","accessed":"2026-08-27"},{"id":"nih_ods_folate_interactions","url":"https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/","label":"NIH ODS — Folate (Health Professional) — Interactions with Medications","quote":"Methotrexate … is a folate antagonist … the supplements could interfere with methotrexate's anticancer effects … Antiepileptic medications … can reduce serum folate levels … Sulfasalazine … inhibits the intestinal absorption of folate","accessed":"2026-08-27"},{"id":"hsa_prohibited","url":"https://file.go.gov.sg/hsa-chp-prohibited-restricted-ing-guidelines.pdf","label":"HSA Singapore — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev. No. 001 (October 2025), Annex A row 47","quote":"47. Folic acid Restricted use in HS and TM Maximum Daily Dose When for oral use by general adult population, the maximum recommended daily dose should not provide more than 0.9mg","accessed":"2026-08-27"},{"id":"hsa_hs_guidelines","url":"https://file.go.gov.sg/hsa-hs-guidelines.pdf","label":"HSA Singapore — Health Supplements Guidelines GL-CHPB-3-001 Rev. No. 020 (January 2026), clause 4.8 and Table 4 Vitamins Limits","quote":"4.8 HS for use by the general adult population should not contain vitamins and minerals exceeding the stipulated limits stated in Tables 4 and 5 … Table 4: Vitamins Limits … Folic acid 0.9mg","accessed":"2026-08-27"},{"id":"iherb_sg","url":"https://sg.iherb.com/c/folic-acid","label":"iHerb Singapore — Vitamin B9 (Folate - Folic Acid) category page, default listing order","quote":"Vitamin B9 … 130 results … California Gold Nutrition, Folinic Acid … Jarrow Formulas, Vegan Methyl Folate … NOW Foods, Folic Acid … Doctor's Best, Fully Active Folate … Life Extension, BioActive Folate & Vitamin B12","accessed":"2026-08-27"}],"brand_certs":null,"updated_at":"2026-08-29T16:16:23.779398+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}