Vitamin K2
Menaquinone
Fat-soluble vitamin that directs calcium to bones. FDA RDI 120 mcg/day. Often paired with Vitamin D3 for bone and cardiovascular health.
FDA Reference Data
About Vitamin K2
Vitamin K2 (menaquinone) directs calcium to bones and teeth while preventing arterial calcification. FDA classifies Vitamin K (K1 and K2) under a single declaration with RDI of 120 mcg/day. K2 exists in multiple forms: MK-4 (short-acting, synthetic), MK-7 (long-acting, fermented, preferred in supplements). Unlike Vitamin D, Vitamin K is voluntary on Supplement Facts but recommended when calcium or Vitamin D is present.
Common Supplement Forms
Note: When a salt form is used, the Supplement Facts panel must declare the elemental amount (e.g., “Magnesium 141 mg 34%”), not the salt weight. The salt name appears in the ingredient list below the panel. See %DV calculator for calculation details.
Frequently Asked Questions
Is Vitamin K2 mandatory on Supplement Facts labels?
No. Only Vitamin D, Calcium, Iron, and Potassium are mandatory per FDA 21 CFR 101.36(b)(2)(i). Vitamin K2 is voluntary and only appears on the Supplement Facts panel if the product contains it. However, if declared, it falls under the broader "Vitamin K" category with RDI 120 mcg/day.
How do I declare Vitamin K2 on a Supplement Facts label?
Declare as "Vitamin K [amount] mcg [%DV]" or "Vitamin K2 (as MK-7) [amount] mcg [%DV]". The form (MK-7, MK-4) may appear in parentheses as the source form. The %DV is calculated against the 120 mcg Vitamin K RDI.
What is the difference between MK-7 and MK-4?
MK-7 (menaquinone-7) has a 72-hour half-life, allowing once-daily dosing. It is naturally produced by bacterial fermentation (natto). MK-4 (menaquinone-4) has a 1-2 hour half-life and requires 3+ daily doses. MK-7 is the preferred form in modern supplements due to dosing convenience and longer-lasting serum levels.
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ReguSift extracts ingredients from your COA, calculates %DV, formats proprietary blends, and generates a print-ready Supplement Facts label — including Vitamin K2 auto-formatted per FDA 21 CFR 101.36.