Vitamin K2
Menaquinone / MK-7 / MK-4 · Foundation
Directs calcium toward bone and away from arteries in theory; the human outcome data is thinner than the pairing with D3 implies.
What the evidence says
The mechanism is real — K2 activates proteins that regulate where calcium is deposited. Human outcome evidence is where it thins: a few bone-density and arterial-stiffness trials with modest or mixed results, and nothing establishing that adding K2 to D3 changes fracture or cardiovascular outcomes. The routine D3+K2 pairing is mechanistic reasoning sold as an established requirement.
What studies used
MK-7 trials commonly used 90–180 mcg/day. Fat-soluble; studies dosed it with meals.
Reported from published studies and product labelling — a record of what was used in research, not a recommendation. What is right for you is a conversation with a clinician.
Watch out for
- Vitamin K directly opposes warfarin — anyone anticoagulated needs their prescriber involved before starting or stopping it, and consistency matters more than amount
Evidence base
established literature
Strong human evidence: either a phase 3 or 4 trial report alongside review-level evidence, or ten or more randomised controlled trial reports.
This letter measures how much human research exists, not whether it works for you — the tier above (Limited) is the read on quality.
Research (12)
- Vitamin K - sources, physiological role, kinetics, deficiency, detection, therapeutic use, and toxicityNutr Rev · 2022
- Vitamin K: Double Bonds beyond Coagulation Insights into Differences between Vitamin K1 and K2 in Health and DiseaseInt J Mol Sci · 2019
- Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal womenOsteoporos Int · 2013
- Vitamin K2 and D in Patients With Aortic Valve Calcification: A Randomized Double-Blinded Clinical TrialCirculation · 2022
- Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women. A double-blind randomised clinical trialThromb Haemost · 2015
- Vitamin K2 supplementation improves impaired glycemic homeostasis and insulin sensitivity for type 2 diabetes through gut microbiome and fecal metabolitesBMC Med · 2023
- [Vitamin K2]Clin Calcium · 2008
- Production and application of menaquinone-7 (vitamin K2): a new perspectiveWorld J Microbiol Biotechnol · 2017
- Safety evaluation of vitamin K2 (menaquinone-7) via toxicological testsSci Rep · 2024
- The effect of menaquinone-7 (vitamin K2) supplementation on osteocalcin carboxylation in healthy prepubertal childrenBr J Nutr · 2009
- Vitamin K2 Alleviates Insulin Resistance Associated Skeletal Muscle Atrophy via the AKT/mTOR Signalling PathwayJ Cachexia Sarcopenia Muscle · 2025
- Niallia tiangongensis sp. nov., isolated from the China Space StationInt J Syst Evol Microbiol · 2025
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