Check before you startThis one has documented interactions with medication classes where the consequences are serious. If you take any prescription medicine, run it past a pharmacist before starting.
Evidence strength
58/100Moderate
WEAKLIMITEDMODERATESTRONGVERY STRONG
What the evidence supports: bone density markers; cardiovascular claims are weaker.
This scores how well-supported the claim above is — not how much benefit you personally would get. A high score on a narrow claim does not extend to everything the product is marketed for.
How long to take it
Ongoing alongside vitamin D, since the dietary sources are genuinely rare in most diets.
Who it's actually for
Anyone supplementing vitamin D long-term, and people managing bone density.
Safe upper limit
Unverified
None established
No formal upper limit, but the warfarin interaction is the hard constraint, not toxicity. No EFSA/NIH UL exists for vitamin K generally, but this needs direct confirmation. The warfarin interaction is the more load-bearing fact here and needs its own check.