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Vitamin K2 (MK-7) Side Effects & Safety

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Generally Safe

Potential Side Effects

  • Very well tolerated at standard supplemental doses
  • No known toxicity even at high doses in clinical trials
  • Theoretical concern about hypercoagulability in those with clotting disorders (not documented with K2)
  • Rare: GI discomfort

Drug & Supplement Interactions

  • Warfarin and other vitamin K antagonist anticoagulants — K2 can reduce anticoagulant effectiveness; use only under medical supervision
  • Vitamin D3 — synergistic for bone health; recommended to combine
  • Calcium supplements — K2 helps ensure calcium is deposited in bones rather than arteries
  • Statins — some evidence suggests statins may inhibit K2 synthesis; supplementation may be beneficial

Maximum Dose

Do not exceed: No established upper limit for K2; doses up to 360 mcg MK-7 daily used safely in trials; MK-4 used at 45 mg/day therapeutically in Japan

Full Vitamin K2 (MK-7) Guide

References

  1. (). Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporosis International. DOI
  2. (). Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study. Journal of Nutrition. DOI
  3. (). Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood. DOI