K2 + D3 combo

Tier 2 — promising · Bone · Cardiovascular · Calcium regulation

Vitamin D3 increases calcium absorption while K2 (MK-7) directs that calcium into bones and away from arteries via carboxylation of osteocalcin and MGP. The combination is biologically sound and widely used, but few RCTs have tested the specific combination versus each vitamin alone. Both are very safe and individually well-supported.

Dose: 1,000–2,000 IU D3 + 100–200 mcg K2 (MK-7) daily; combination logic is sound but not directly validated