How much K2 per day? The U.S. reference is for vitamin K overall

K2 is a family of forms

Vitamin K2 refers to menaquinones, including MK-4 and MK-7. The U.S. adult Adequate Intake for vitamin K is 120 mcg daily for men and 90 mcg for women. ODS presents these as vitamin K intake values, not a requirement to swallow that amount of K2 in addition to food or K1. An Adequate Intake is used when evidence is insufficient to set an RDA. [1]

A supplement amount needs its own rationale

A label’s MK-7 quantity, a trial’s MK-4 regimen and the general vitamin K intake reference answer different questions. They cannot be treated as interchangeable just because all contain vitamin K. No established upper limit does not mean any amount is beneficial or suitable. People taking warfarin need consistent intake and clinical advice before changing vitamin K supplements. [1]

A hypothetical unit trap

Imagine one label says 100 mcg MK-7 and another says 1 mg MK-4. One milligram equals 1,000 mcg; the second number is ten times the mass, and the form is different. This does not identify a preferred dose or prove that one product has ten times the effect. [1]

Hypothetical example — interpret a specific hypothetical label or comparison
Hypothetical declaration	Interpretation
100 mcg MK-7	One specified menaquinone amount
1 mg MK-4	1,000 mcg of a different menaquinone

How much K2 per day? The U.S. reference is for vitamin K overall — original article outline diagram — Original editorial diagram of this article’s sections; no product photograph or clinical finding is depicted.

Sources for this article

Vitamin K - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.