NSTK · 01.2026Independent supplement reference
NutriStack
Edition 1.0Updated August 1, 2026

Supplement × Supplement·Evidence index

Vitamin K1 and Vitamin K2: what the published research says

PubMed indexes 4 records that name Vitamin K1 and Vitamin K2 together, either in the title or in an interaction, co-administration, or pharmacokinetic context. Each one is listed below with its study design and, where the abstract states one, the authors’ own conclusion, quoted and linked. This page reports that literature. It does not tell you whether to combine them.

Read this first

An evidence index, not guidance.

Every statement below is attributed to a named, dated, linked source.

This page lists published research relevant to Vitamin K1 and Vitamin K2. It deliberately does not state whether the combination is safe, whether it interacts, in which direction, at what dose, or how far apart to take them.

The research

4 studies naming Vitamin K1 and Vitamin K2.

Strongest relevance first: papers naming both substances in the title, then human trials and systematic reviews.

Vitamin K2 Needs an RDI Separate from Vitamin K1.

Nutrients · 2020 · PMID 32575901

ReviewHuman subjects

“In this review, we highlight the specific activity of vitamin K2 based upon proposed frameworks necessary for a bioactive substance to be recommended for an RDI. Vitamin K2 meets all these criteria and should be considered for a specific dietary recommendation intake.”

Akbulut et al. · From the abstract

Names both Vitamin K1 and Vitamin K2 in its title.

Plasma phylloquinone, menaquinone-4 and menaquinone-7 levels and coronary artery calcification.

Journal of nutritional science · 2016 · PMID 28620475

103 participants

“However, CAC did not have a significant correlation with plasma levels of PK, MK-4 or MK-7. In conclusion, plasma MK-7, MK-4 or PK level did not show significant correlation with CAC despite the association between plasma vitamin K levels and vitamin K-dependent proteins such as ucOC or PIVKA-2.”

Torii et al. · From the abstract

Names both Vitamin K1 and Vitamin K2 in its title.

Vitamin K1 (phylloquinone) or vitamin K2 (menaquinone-4) induces intestinal alkaline phosphatase gene expression.

Journal of nutritional science and vitaminology · 2011 · PMID 22041909

Animal study

“This is the first report concerning IAP mRNA expression induced by oral administration of vitamin K. The results support the possible involvement of vitamin K in the regulation of IAP mRNA expression as a novel pharmacological effect of vitamin K.”

Haraikawa et al. · From the abstract

Names both Vitamin K1 and Vitamin K2 in its title.

Low vitamin K1 intake in haemodialysis patients.

Clinical nutrition (Edinburgh, Scotland) · 2017 · PMID 27234935

Multicenter StudyObservational StudyHuman subjects

“Haemodialysis patients had a significantly low intake in vitamin K1, which could contribute to increase the risk of bone fractures and vascular calcifications. Since the deficiency of vitamin K intake seems to be remarkable, dietary counselling to HD patients should also address the adequacy of vitamin K dietary intake and bioavailability.”

Fusaro et al. · Authors' conclusion

Names Vitamin K1 and Vitamin K2 together in an interaction, co-administration, or pharmacokinetic context.

Limitations

What this evidence cannot tell you.

Search-based evidence indexes have real limits, and it is worth being explicit about them:

NutriStack

Track what you actually take.

NutriStack is a free iPhone app for organising a supplement routine: what you take, when, and what the published record says about it. Its exploratory interaction checker covers Vitamin K1, Vitamin K2, and several hundred other substances.

The checker is a research and organisation tool, not a clinical decision aid, and its per-pair assessments are excluded from search until they pass claim-level review.

NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.