Vitamin K2 Supplements: Benefits, Dosage and Safety
Vitamin K2 supplements activate proteins that use calcium in bone and blood vessels. The theory behind pairing K2 with vitamin D is plausible, but trials on bone and artery outcomes are mixed. K2 is generally safe, except for people taking warfarin, where it can interfere with treatment.
Evidence at a glance
| Use | Grade | What the research shows |
|---|---|---|
| Bone density | C | Mixed results; high-dose MK-4 studied in Japan. |
| Arterial calcification | C | Trials mostly show no significant benefit. |
A: strong, consistent human evidence · B: moderate · C: limited or mixed · D: good evidence of no benefit.
Vitamin K comes as K1 (leafy greens) and K2 (fermented foods such as natto, some cheeses).
How to take it
Typical doses are 90–200 mcg of MK-7 a day, taken with a meal containing fat. Read can you take vitamin D and K2 together.
Safety and interactions
Don't take vitamin K supplements with warfarin unless your prescriber agrees; keep intake consistent.
Always tell your doctor and pharmacist about the supplements you take. Check combinations with our interaction checker.
Sources
This page is for education and is not a substitute for advice from your doctor. Read our medical disclaimer.