Vitamin K2 (MK-7)
- Effective dose
- 90–180 mcg
- Evidence
- 3/5· Moderate
Last updated June 1, 2026
What it is
Vitamin K2 as menaquinone-7 (MK-7) is a fat-soluble vitamin produced by bacterial fermentation and found in foods like natto. It acts as a cofactor for the enzyme that activates vitamin K-dependent proteins, including those that direct calcium into bone and away from arterial walls.
Benefits
MK-7 supports bone metabolism and arterial calcium handling; 180 mcg/day for 3 years improved bone strength and slowed vertebral height loss in postmenopausal women.
When to take it
Taken daily with a meal containing fat to aid absorption; timing within the day does not matter as long as intake is consistent.
Side effects
Very low toxicity and no established upper limit; no adverse effects reported from food or supplements. Critically, anyone taking warfarin must keep vitamin K intake consistent, as changes can dangerously alter anticoagulation.
Sources
Products containing Vitamin K2 (MK-7)
No products in our database contain this ingredient yet.