How strong is the evidence behind Vitamin K2 and Vitamin K2 MK-4 for this claim?

NutriStack rates this as Moderate evidence, meaning several aligned RCTs or one large RCT plus supporting reviews. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.

What contrary evidence or caveats apply?

Trials are concentrated in postmenopausal women; data in men is thinner. Many positive trials are Japanese and use dosing that western trials do not replicate.

Show your sourcesModerate evidenceReviewed May 2026

Vitamin K2 supports bone density and reduces fracture risk, the receipts.

Especially well-supported for MK-4 at high pharmacologic doses (45 mg/day in Japanese trials). MK-7 at 180 mcg/day shows modest BMD preservation in postmenopausal women.

6 of 18 matching studies surfaced. NutriStack rating: moderate evidence. Last reviewed May 26, 2026.

How we tier evidence →Browse all claim deep dives

Moderate evidence, per the methodology. Strongest 6 studies linked to PubMed.
Recommendation, contrary evidence, and dose are all on this page.

The studies·Contrary evidence·Recommendation

The studies

Strongest evidence, sourced.

Sorted by study tier (meta-analyses first, then RCTs, then reviews) and recency. Every entry links to PubMed by PMID.

At a glance

Substances: Vitamin K2, Vitamin K2 MK-4
Evidence tier: Moderate evidence
Strongest studies surfaced: 6 of 18 matching
One-line verdict: Most defensible in postmenopausal women.
Last verified: May 30, 2026

Top 6 studies

RCT Rønn SH, Harsløf T, Oei L et al., Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA 2021

The effect of vitamin MK-7 on bone mineral density and microarchitecture in postmenopausal women with osteopenia, a 3-year randomized, placebo-controlled clinical trial PMID 33030563
RCT Knapen MH et al., Bone 2016

Vitamin K2 (menaquinone-7) prevents age-related deterioration of trabecular bone microarchitecture at the tibia in postmenopausal women PMID 27625301

MK-7 prevented age-related deterioration of trabecular bone microarchitecture at the tibia in healthy postmenopausal women over 3 years
RCT Inaba N et al., J Nutr Sci Vitaminol 2015

Low-Dose Daily Intake of Vitamin K(2) (Menaquinone-7) Improves Osteocalcin gamma-Carboxylation: A Double-Blind, Randomized Controlled Trials PMID 26875489

Menaquinone-7 increased carboxylated/undercarboxylated osteocalcin ratio dose-dependently; daily intake >=100 mcg suggested for optimal gamma-carboxylation
RCT Koitaya N et al., J Bone Miner Metab 2014

Low-dose vitamin K2 (MK-4) supplementation for 12 months improves bone metabolism and prevents forearm bone loss in postmenopausal Japanese women PMID 23702931

Low-dose MK-4 (1.5 mg/day) for 12 months improved bone turnover markers and prevented forearm bone mineral density loss in postmenopausal women aged 50-65.
RCT Nakamura E, Aoki M, Watanabe F et al., Nutrition journal 2014

Low-dose menaquinone-4 improves γ-carboxylation of osteocalcin in young males: a non-placebo-controlled dose-response study PMID 25163392
RCT Knapen MH et al., Osteoporos Int 2013

Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women PMID 23525894

MK-7 supplementation significantly decreased age-related decline in bone mineral content and bone mineral density at femoral neck; also improved bone strength

Contrary evidence

What pushes back.

Caveats, null findings, and methodological limits that hold the tier where it is.

What argues against the claim

Trials are concentrated in postmenopausal women; data in men is thinner.
Many positive trials are Japanese and use dosing that western trials do not replicate.

Recommendation

What the evidence supports.

What we recommend, with caveats

180 to 360 mcg/day MK-7 alongside vitamin D and adequate calcium. The 45 mg/day MK-4 dose used in Japanese fracture trials is a pharmaceutical dose, not a standard supplement dose.

Tier criteria are documented at /methodology/evidence-tiers. Sourcing standards at /methodology/interactions.

Stack interaction risks

Where these substances clash.

Documented pairings involving the substances behind this claim. Cautions and conflicts come first.

Pairs in the database

Open the free interaction checker at /interactions to scan a full routine.

Goal hubs

Where this claim feeds in.

Goal-based hubs that index this claim alongside related supplements and protocols.

Related goal hubs

Bone Health

Before you go

One claim, opened up. NutriStack does this for every claim in the database.

The full library lives at /research. Every entry follows the same shape: the verdict, the studies, the contrary evidence, the recommendation, and the primary literature.

Browse all claim deep dives →Read the methodology