The D3+K2 combination is synergistic for calcium metabolism: vitamin D3 increases calcium ABSORPTION from the gut, while vitamin K2 (MK-7) DIRECTS that calcium to bones instead of arteries. Without K2, high-dose D3 supplementation may increase arterial calcification (the 'calcium paradox'). K2 activates osteocalcin (bone) and matrix-Gla protein (anti-calcification). A 2015 study found D3+K2 (1,000 IU + 45μg MK-7) improved bone density significantly more than D3 alone. This combination should be the default for anyone taking vitamin D. --- *Reviewed by the Dose AI Research Team and Clinical Advisory Board* *Last updated: 2026-04-06*
Based on independent third-party laboratory analysis
Category pass rate: ~90% pass rate. One notable failure: Biotics Research at 195% of label (nearly double).
Reviewed by the Scan Dose Research Team and Clinical Advisory Board | Last updated:
Not medical advice. Based on published clinical research and systematic reviews.