L-methylfolate
L-methylfolate suppliers and sourcing guide
L-methylfolate is (6S)-5-methyltetrahydrofolate (L-5-MTHF), the reduced, methylated form of folate, sold mainly as its calcium salt and also as glucosamine or sodium salts. It is made by chemical synthesis from folic acid: the folic acid is reduced and methylated, and the natural 6S isomer is separated from the 6R form and crystallized. Several suppliers sell it under trade names, and because amounts per serving are in micrograms, it is bought both as pure salt and as diluted powders.
- Category
- Vitamins and minerals
- Also known as
- Calcium L-methylfolate · L-5-methyltetrahydrofolate (L-5-MTHF) · Levomefolate calcium · (6S)-5-methyltetrahydrofolate
- Facts checked
- November 2026
Forms and grades of L-methylfolate
Suppliers sell different products under the same name. Specify the one you need.
Calcium salt
The most common form, a crystalline powder; suppliers offer different crystal forms with their own stability data.
Glucosamine salt
A more water-soluble salt of L-5-MTHF offered by some suppliers.
Sodium salt
Monosodium L-5-MTHF, a newer water-soluble form from some suppliers.
Diluted powders
L-methylfolate on a carrier at a stated percentage for easier microgram dosing.
Racemic (6R,S) material
A mixture of both isomers, cheaper but only about half the natural 6S form; specify the 6S isomer and its minimum purity.
What to check on the COA
Compare each result with your own specification when the lot arrives.
- Assay (HPLC)
- L-5-MTHF content by HPLC, stated as the salt or the free acid; check which.
- Isomer purity
- Ratio of the 6S to 6R isomer by chiral HPLC.
- Related substances
- Folic acid, tetrahydrofolate and oxidation products by HPLC.
- Water (Karl Fischer)
- Water content, which affects both potency and stability.
- Counter-ion content
- Calcium, sodium or glucosamine content checked against the salt's theoretical value.
- Heavy metals and residual solvents
- Lead and other elemental impurities by ICP-MS and synthesis solvents by GC.
Storage, lots and expiry
Storage and shelf life
L-methylfolate is sensitive to oxygen, heat, light and moisture, so it is supplied in sealed, often nitrogen-flushed packaging; store it exactly as the supplier specifies, which can include refrigeration. Use opened containers promptly and reseal them well. Shelf life comes from the supplier specification, with assay and related substances as the retest checks.
Lots and expiry dates
Record assay basis, isomer purity and water for each lot, and convert from salt weight to L-5-MTHF using the supplier's stated factor. Rotate FEFO and keep different salt forms as separate items.
Regulatory status
Facts from regulators and standards bodies, each linked to its source.
GRN 915 (calcium L-methylfolate, notified by DSM Nutritional Products for infant formulas as a partial or complete replacement for folic acid) closed on February 23, 2021 with FDA having no questions.
Source: hfpappexternal.fda.gov (opens in a new tab)Under 21 CFR 101.9, the nutrient name "folate" is used for products containing synthetic folate in dietary supplements, with the calcium salt of L-5-MTHF given as an example.
Source: ecfr.gov (opens in a new tab)Health Canada's Multi-Vitamin/Mineral Supplements monograph lists L-5-methyltetrahydrofolate and its calcium salt as a source ingredient for folate.
Source: webprod.hc-sc.gc.ca (opens in a new tab)
This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.
L-methylfolate suppliers
Manufacturers and distributors whose own websites say they sell it.
We are checking L-methylfolate suppliers now
Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.
Sell L-methylfolate? Request a listingFrequently asked questions
What forms of L-methylfolate can brands buy?
Common forms include calcium salt, glucosamine salt, sodium salt, diluted powders and racemic (6R,S) material. Ask each supplier for the specification sheet of the exact grade they quote.
What should the COA for L-methylfolate include?
Expect assay (HPLC), isomer purity, related substances, water (Karl Fischer), counter-ion content and heavy metals and residual solvents, each with its method, specification and result for that lot.
How should L-methylfolate be stored?
L-methylfolate is sensitive to oxygen, heat, light and moisture, so it is supplied in sealed, often nitrogen-flushed packaging; store it exactly as the supplier specifies, which can include refrigeration. Use opened containers promptly and reseal them well. Shelf life comes from the supplier specification, with assay and related substances as the retest checks.
What is the regulatory status of L-methylfolate?
GRN 915 (calcium L-methylfolate, notified by DSM Nutritional Products for infant formulas as a partial or complete replacement for folic acid) closed on February 23, 2021 with FDA having no questions. Under 21 CFR 101.9, the nutrient name "folate" is used for products containing synthetic folate in dietary supplements, with the calcium salt of L-5-MTHF given as an example. Health Canada's Multi-Vitamin/Mineral Supplements monograph lists L-5-methyltetrahydrofolate and its calcium salt as a source ingredient for folate.
More vitamins and minerals
- Magnesium GlycinateMagnesium bisglycinate · Magnesium bisglycinate chelate
- Vitamin CL-ascorbic acid · Ascorbic acid
- Vitamin D3Cholecalciferol · Colecalciferol
- ZincZinc citrate · Zinc gluconate
- Vitamin A palmitateRetinyl palmitate · Retinol palmitate
- Vitamin A acetateRetinyl acetate · Retinol acetate
- Beta-caroteneβ-Carotene · all-trans-beta-carotene
- Vitamin D2Ergocalciferol · Calciferol
- Vitamin E (d-alpha tocopherol)d-alpha-tocopherol · RRR-alpha-tocopherol
- Mixed tocopherolsTocopherols concentrate, mixed · Mixed tocopherol concentrate
- Vitamin K1Phylloquinone · Phytonadione
- Vitamin K2 (MK-7)Menaquinone-7 · MK-7
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