Vitamin K2 (MK-4)
Vitamin K2 as menaquinone-4 (MK-4, menatetrenone) is a menaquinone with a side chain of four isoprene units, a pale yellow crystalline solid or oil. Commercial MK-4 is made by chemical synthesis, attaching a 20-carbon isoprenoid side chain to a naphthoquinone ring, rather than by fermentation. Products use it at amounts from micrograms to milligrams per serving, so it is sold both as high-purity material and as diluted powders and oil solutions.
Suppliers sell different products under the same name. Specify the one you need.
Crystalline or oily MK-4 at high purity, for products using milligram amounts and for premix makers.
MK-4 on a carrier such as microcrystalline cellulose or starch at a stated percentage, for microgram-level dosing.
MK-4 dissolved in vegetable or MCT oil, for softgels and drops.
Coated MK-4 made to hold up better in mineral-containing blends and against light.
Compare each result with your own specification when the lot arrives.
MK-4 is light-sensitive and degrades with heat and in alkaline conditions, so keep it sealed in light-proof packaging in a cool, dry place. Use opened containers promptly and reseal them well. Suppliers set shelf life, and HPLC assay is the usual retest check.
Record assay and isomer content for each lot and dose from the actual assay. Keep MK-4 and MK-7 as clearly separate items, since they are different ingredients on the label.
Facts from regulators and standards bodies, each linked to its source.
Health Canada's Multi-Vitamin/Mineral Supplements monograph lists menaquinone 4 and menatetrenone among the names given for vitamin K2 source ingredients.
Source: webprod.hc-sc.gc.ca (opens in a new tab)21 CFR 101.9(c)(8)(iv) sets the Reference Daily Intake for vitamin K at 120 mcg for adults and children 4 years and older.
Source: ecfr.gov (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.
Manufacturers and distributors whose own websites say they sell it.
Manufacturer · Rancho Santa Margarita, CA
California ingredient company that makes nature-identical specialty nutrients by fermentation and bioconversion, including ergothioneine, L-theanine, hydroxytyrosol, pterostilbene and vitamin K2.
Manufacturer · New York, NY
North American sales office of Kyowa Hakko Bio, a Japanese fermentation company. It sells branded glutathione and citicoline plus pyridoxal-5'-phosphate and vitamin K2 (MK-4) to supplement and food makers.
Suppliers are in alphabetical order and none pays to appear. Each claim is checked against the supplier’s own website on the date shown. Ask for the specification sheet and a recent COA before you order, and confirm details with the supplier.
Common forms include high-purity MK-4, powder dilutions, oil solutions and microencapsulated grades. Ask each supplier for the specification sheet of the exact grade they quote.
Expect assay (HPLC), all-trans content and related substances, identity, residual solvents and heavy metals and microbiology, each with its method, specification and result for that lot.
MK-4 is light-sensitive and degrades with heat and in alkaline conditions, so keep it sealed in light-proof packaging in a cool, dry place. Use opened containers promptly and reseal them well. Suppliers set shelf life, and HPLC assay is the usual retest check.
Health Canada's Multi-Vitamin/Mineral Supplements monograph lists menaquinone 4 and menatetrenone among the names given for vitamin K2 source ingredients. 21 CFR 101.9(c)(8)(iv) sets the Reference Daily Intake for vitamin K at 120 mcg for adults and children 4 years and older.
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