What kind of interaction is it?

Synergy: a documented combination effect that is stronger or more useful than either substance taken alone.

Is this interaction backed by published research?

Yes. NutriStack lists 4 citation rows for the Calcium + Vitamin K2 pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Interaction databaseSupplement × SupplementReviewed May 2026

Calcium and Vitamin K2, a synergy.

Q: Can I take Calcium and Vitamin K2 together?

Yes. The combination of Calcium and Vitamin K2 produces a measurable benefit. K2 activates osteocalcin to direct calcium to bones and matrix GLA protein to prevent arterial calcification. Essential when supplementing calcium.

Q: How does this affect a NutriStack Stack Score?

+2 to your Stack Score per scored synergy row.

K2 activates osteocalcin to direct calcium to bones and matrix GLA protein to prevent arterial calcification. Essential when supplementing calcium.

4 primary source citations. Strong evidence. Last verified May 30, 2026.

Open the interaction checker →Read the methodology

One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.

Sourcing standards·Evidence tiers

From the interaction database

What the row says.

Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.

At a glance

Substances: Calcium and Vitamin K2
Pair type: Synergy
Evidence (highest tier): Strong
Source citations: 4 sources
Stack Score effect: +2 to your Stack Score (per scored synergy row).
Scope: Supplement × Supplement
Last verified: May 30, 2026

Synergy · Strong evidence

Synergy

What is happening. K2 activates osteocalcin to direct calcium to bones and matrix GLA protein to prevent arterial calcification. Essential when supplementing calcium.

Mechanism. K2-dependent carboxylation of osteocalcin enables it to bind calcium and deposit it in bone matrix. MGP carboxylation by K2 prevents calcium deposition in arterial walls.

Recommendation. Always take K2 (MK-7, 100-200mcg) when supplementing calcium to ensure proper calcium deposition in bones, not arteries.

Sources (4)

Knapen MH et al. Menaquinone-7 supplementation improves arterial stiffness. Thromb Haemost. 2015
Kuang X, Liu C, Guo X, Li K, Deng Q, Li D. The combination effect of vitamin K and vitamin D on human bone quality: a meta-analysis of randomized controlled trials. Food & Function. 2020. PMID 32219282
Liu C, Kuang X, Li K, Guo X, Deng Q, Li D. Effects of combined calcium and vitamin D supplementation on osteoporosis in postmenopausal women: a systematic review and meta-analysis of randomized controlled trials. Food & Function. 2020. PMID 33237064
Yao P, Bennett D, Mafham M et al.. Vitamin D and Calcium for the Prevention of Fracture: A Systematic Review and Meta-analysis. JAMA Network Open. 2019. PMID 31860103

Stack Score

How this pair moves the number.

Effect on the composite score

If both Calcium and Vitamin K2 are in the same stack, this pair applies +2 to your Stack Score (per scored synergy row).

The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.

Check your full routine

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Open the interaction checker →Browse the full research index