Safety · Supplement
Vitamin K2: side effects, safety & interactions
Very safe. The critical exception: K2 (like K1) antagonizes warfarin and other vitamin-K-antagonist anticoagulants — any
- Overall grade
- Grade B
- Last revised
- 0
- graded outcomes
- 1
- reference listed
Assembled by the app from other entries in this library. It adds no evidence of its own — follow the links to the entries it draws on.
The evidence in words
Safety profile
Very safe. The critical exception: K2 (like K1) antagonizes warfarin and other vitamin-K-antagonist anticoagulants — anyone on warfarin must keep vitamin K intake consistent and cleared with their prescriber. It does not interact with the newer DOAC anticoagulants.
Interactions to respect
Anticoagulants (warfarin) — Antagonizes vitamin-K-antagonist anticoagulants; keep intake constant and clear it medically.
What Vitamin K2 is
Vitamin K exists as K1 (phylloquinone, from greens, drives clotting) and K2 (menaquinones, from ferments and animal foods, drives tissue calcium handling). MK-7 is the long-acting K2 form used in supplements. It is distinct from K1 in half-life and tissue distribution.
The honest bottom line
A cheap, low-risk companion to vitamin D that makes mechanistic sense for bone and vascular calcium handling. 90–180 µg MK-7 with your D. If you take warfarin, do not add it without medical guidance.
Related reading
Entries that share this one's tags or conditions.
- Calcium: side effects, safety & interactionsConstipation and, at high supplemental doses, kidney-stone and possibly cardiovascular concerns. Prefer dietary calcium Evidence grade B
- Krill Oil: side effects, safety & interactionsSafe; shellfish-allergy caution. Mild antiplatelet effect like other omega-3s.Evidence grade C
- Silicon: side effects, safety & interactionsSafe at supplemental doses.Evidence grade C
- Vitamin D: side effects, safety & interactionsVery safe in the ordinary range; toxicity (hypercalcemia) is real but requires sustained megadosing, typically well abovEvidence grade A
Sources
As this entry records them: title, journal and year. None carries a DOI or PubMed id, so none is linked as a verified paper. Each link searches PubMed for the title; check that what you find is what the entry describes.
- 1.Menaquinone-7 supplementation and arterial stiffness — Thromb Haemost, 2015. Search PubMed (opens in a new tab)
Last revised . A grade is this entry's reading of the evidence, not medical advice.