Vitamin ·Moderate evidence ·Reviewed May 2026
Short-acting form of K2 that reaches bone and brain tissue rapidly.
The bottom line
Evidence rating moderate. Most-documented uses: bone health, brain health, dental health. 16 sources indexed (2000–2023), with 9 interaction records on file.
Core mechanism
Rapidly absorbed, short half-life (~6 hours vs MK-7's ~72 hours). Preferentially activates osteocalcin in bone. May have unique effects on gene expression via SXR/PXR nuclear receptor.7
Ranked by evidence and value.
Real-world pricing across three quality tiers. Assumes Vitamin K2 MK-4.
Assumes a practical daily MK-4 dose. MK-4 products are usually costlier than MK-7 because doses are larger and repeat dosing is common. Updated 2026-04-02.
How much you'd eat to match a supplemental dose.
MK-4 supplement doses are usually much higher than what food alone provides.
Timing: Split 2-3 doses with meals
MK-4 is short acting and often dosed more than once daily.
Timing: With meals
Shorter half-life than MK-7; consistency matters.
What to test, the optimal window inside the conventional range, and how long a response takes.
Where this appears in the symptom-to-supplement map, ranked by relevance.
MK-4 supports osteocalcin activation and alveolar bone remodeling.1,4
MK-4 vs MK-7 trade-offs: MK-4 short half-life, MK-7 longer.
Vitamin K intake has special relevance for people using warfarin because VKORC1 and CYP2C9 genotype influence warfarin sensitivity and dose requirements (PMID 20653669).
Recommendation: Keep vitamin K intake consistent and coordinate any vitamin K supplement with the prescriber if taking warfarin or another vitamin K antagonist.
Vitamin D3 increases calcium absorption, while K2 activates osteocalcin and matrix GLA protein to direct calcium into bones and away from arteries.
Recommendation: Take together. K2 (MK-7 100-200mcg) is recommended whenever supplementing D3 above 2000 IU.
K1 primarily supports coagulation while K2 (MK-7) directs calcium to bones. Complementary roles in vitamin K metabolism.
Recommendation: Both forms are beneficial. K2 (MK-7) has a longer half-life and better extrahepatic distribution than K1.
K2 activates osteocalcin to direct calcium to bones and matrix GLA protein to prevent arterial calcification. Essential when supplementing calcium.
Recommendation: Always take K2 (MK-7, 100-200mcg) when supplementing calcium to ensure proper calcium deposition in bones, not arteries.
K2 (MK-7) is fat-soluble and absorption increases with dietary fat. Fish oil provides an excellent fat vehicle.
Recommendation: Take K2 with fish oil or a fat-containing meal for optimal absorption.
High-dose vitamin E may reduce K2-dependent protein carboxylation, potentially affecting both bone and cardiovascular K2 benefits.
Recommendation: Keep vitamin E at moderate doses (200 IU or less) when relying on K2 for bone and cardiovascular health.
MCT Oil provides a fat-containing carrier that can improve absorption of fat-soluble compounds like Vitamin K2 MK-4.
Recommendation: Take Vitamin K2 MK-4 with MCT Oil or another fat-containing meal to improve absorption.
Flaxseed Oil provides a fat-containing carrier that can improve absorption of fat-soluble compounds like Vitamin K2 MK-4.
Recommendation: Take Vitamin K2 MK-4 with Flaxseed Oil or another fat-containing meal to improve absorption.
Evening Primrose Oil provides a fat-containing carrier that can improve absorption of fat-soluble compounds like Vitamin K2 MK-4.
Recommendation: Take Vitamin K2 MK-4 with Evening Primrose Oil or another fat-containing meal to improve absorption.
Vitamin K2 in the MK-4 (menatetrenone) form opposes warfarin in the same way as K1 and K2 MK-7: it restores production of vitamin K-dependent clotting factors. MK-4 is used clinically (often intravenously) to reverse warfarin, which is direct evidence that supplemental MK-4 will reduce warfarin's effect. Even modest oral doses can blunt anticoagulation.
Recommendation: Avoid vitamin K2 MK-4 supplements while taking warfarin unless your prescriber has explicitly approved it. If you cannot avoid it, keep the dose and timing identical every day and ask for an INR check within 1-2 weeks of starting.
Numbered references. Citations throughout the page link here.
Meta-analysis of 16 RCTs (6,425 subjects) showed VK2 significantly improves lumbar spine BMD, reduces fracture incidence, and decreases uncarboxylated osteocalcin in postmenopausal women.
Meta-analysis of Japanese MK-4 trials showed significant fracture reduction: OR 0.40 for vertebral, 0.23 for hip, and 0.19 for all nonvertebral fractures.
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.
Nakamura E, Aoki M, Watanabe F et al.. Low-dose menaquinone-4 improves γ-carboxylation of osteocalcin in young males: a non-placebo-controlled dose-response study. Nutrition journal. 2014
Sato Y, Honda Y, Umeno K et al.. The prevention of hip fracture with menatetrenone and risedronate plus calcium supplementation in elderly patients with Alzheimer disease: a randomized controlled trial. The Kurume medical journal. 2011
Inoue T, Fujita T, Kishimoto H et al.. Randomized controlled study on the prevention of osteoporotic fractures (OF study): a phase IV clinical study of 15-mg menatetrenone capsules. Journal of bone and mineral metabolism. 2009
Shiraki M, Itabashi A. Short-term menatetrenone therapy increases gamma-carboxylation of osteocalcin with a moderate increase of bone turnover in postmenopausal osteoporosis: a randomized prospective study. Journal of bone and mineral metabolism. 2009
In 241 osteoporotic patients over 24 months, 45 mg/day vitamin K2 significantly reduced clinical fracture incidence and maintained lumbar BMD compared to untreated controls.
Comprehensive review confirming MK-4's unique functions as SXR/PXR ligand, mitochondrial electron carrier, and transcriptional regulator, with roles beyond carboxylation in bone and brain.
Meinitzer A, Enko D, Zelzer S et al.. Development of a liquid chromatography mass spectrometry method for the determination of vitamin K1, menaquinone-4, menaquinone-7 and vitamin K1-2,3 epoxide in serum of individuals without vitamin K supplements. Clinical chemistry and laboratory medicine. 2022
Koitaya N, Ezaki J, Nishimuta M et al.. Effect of low dose vitamin K2 (MK-4) supplementation on bio-indices in postmenopausal Japanese women. Journal of nutritional science and vitaminology. 2009
Mizuta T, Ozaki I, Eguchi Y et al.. The effect of menatetrenone, a vitamin K2 analog, on disease recurrence and survival in patients with hepatocellular carcinoma after curative treatment: a pilot study. Cancer. 2006
MK-4 increased SOD activity and GLT-1 mRNA levels in brain, inhibiting oxidative stress and neurotoxicity, demonstrating neuroprotective effects against cerebral ischemia/reperfusion injury.
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