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Vitamin K2 (Menaquinone)

Vitamin K2 (Menaquinone)

Best for

Lower fracture risk

Proven benefit 45 mg/day 104 weeks 2 meta-analyses, n=4.5k #1 of 5 studied

  • 27 papers
  • 4 of 56 outcomes
  • 4 positive

Vitamin K2 (menaquinone) provides a proven benefit for reducing fragility fracture risk, with additional bone-density support in postmenopausal women, especially when the studied form and dose are matched.

What vitamin k2 (menaquinone) actually does

Outcome Effect Evidence Dose Time Rank
Clear benefits 2
Lower fracture risk Proven benefit Fractures can limit mobility and independence, especially after a fall.
moderate 		2 meta-analyses 2 papers · n=4.5k 45 mg 104 wk #1 /5
Build bone density Likely benefit Bone density reflects the mineral that helps bones bear weight and resist breaking.
moderate 		2 meta-analyses 6 papers · n=623 — 26–156 wk #2 /14
Early research 2
Slower artery hardening with atherosclerosis Faint early signal Atherosclerosis is plaque buildup in arteries that can restrict blood flow.
small 		6 RCTs 6 papers · n=405 180–400 mcg 26–104 wk #1 /6
Build stronger bones Faint early signal A bone's strength and shape help it handle force without breaking.
small 		1 RCT 1 papers · n=257 45 mg 156 wk —

Effect tiers come from native-unit MCID where available, Cohen's d otherwise.

Protocol

Dose, timing & forms

How much

For bone outcomes, the clearest fracture trials used 45 mg daily of MK-4 for long periods, while a major bone-density trial used 180 mcg daily of MK-7 for three years.12 Those numbers are not interchangeable: MK-4 and MK-7 are different menaquinones, so copy the dose used for the exact form on your label. Bone changes move slowly, and the positive trials measured outcomes over years rather than weeks.12

When and how long

The useful pattern is consistency. Bone trials gave K2 every day for years, so treat it as part of a daily routine rather than something to use occasionally.12 Take it with a meal that contains some fat, since vitamin K is fat-soluble and dietary fat supports its absorption.4 No trial establishes that morning versus evening changes bone results.

Forms & standardisation

MK-4 and MK-7 have the best clinical trial coverage, but they are not the same ingredient at different label strengths. Look for the full form name, such as menaquinone-4 or menaquinone-7, rather than a label that only says "vitamin K2."12 The longer-term MK-7 trial used a defined MK-7 preparation, while fracture research prominently used menatetrenone, an MK-4 form.12

Buy well

Recommended Vitamin K2 (Menaquinone) products

Real products that dose Vitamin K2 (Menaquinone) where the research does, in a clean formulation, from brands we've audited. We only list ones we'd stand behind.

Chosen for adequate Vitamin K2 (Menaquinone) dosing vs. the studied range, a clean formulation (grade A–C), and independent brand-quality audits. Not sponsored.

In context

What this is and how it works

  • Across 2 studies (n=4,508), vitamin K2 lowered fragility fracture risk in postmenopausal osteoporosis populations.1
  • Twenty-seven papers reviewed here span 56 outcomes, including six studies of hip and spine bone density.
  • Evidence varies by menaquinone form and dose; high-dose MK-4 findings do not automatically apply to low-dose MK-7 products.12

Vitamin K2 describes a family of compounds called menaquinones. You get smaller amounts from foods such as fermented foods, egg yolks, and some cheeses, while supplements usually feature MK-4 or MK-7. Unlike vitamin K1, which dominates in leafy greens, K2 products target longer-term bone and vascular questions.4

K2 activates proteins such as osteocalcin and matrix Gla protein through a chemical switch that lets them bind calcium. Think of it as putting working address labels on calcium: osteocalcin helps incorporate it into bone, while matrix Gla protein operates in blood vessel tissue.23 This biology fits the stronger long-term bone findings, but it does not prove that K2 reverses hardened arteries.13

Bottom line

K2 makes the most sense for people focused on long-term bone support, especially after menopause, who are willing to pair it with the basics: adequate nutrition, resistance exercise, and medical bone care when needed. The fracture and bone-density evidence is encouraging but form-specific, so do not assume any low-dose K2 product reproduces a high-dose MK-4 trial.12 Skip self-directed use if you take prescription medicines that alter blood clotting, and get individualized guidance first.4

Frequently asked

Common questions

What is the difference between vitamin K1 and vitamin K2?

Vitamin K1 mainly comes from leafy greens and plays a central role in normal blood clotting. Vitamin K2 is a family of menaquinones found in some fermented and animal foods, and clinical trials have focused on its role in activating proteins involved in bone mineral handling.4

Does vitamin K2 improve bone density?

Long-term trials in postmenopausal women show that specific K2 forms support bone density at the hip and spine. The strongest evidence comes from sustained use, not short-term supplementation.12

Does vitamin K2 clear calcium from arteries?

No clinical trial establishes that K2 clears artery calcium. Early research has explored arterial stiffness and calcium-related measures, but the observed effects are small and too uncertain to treat K2 as a cardiovascular solution.3

Sources

Sources

  1. 1. The effect of menatetrenone on bone mineral density and incidence of clinical fractures in postmenopausal osteoporosis (2000) ↑
  2. 2. Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women (2013) ↑
  3. 3. Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women: double-blind randomised clinical trial (2015) ↑
  4. 4. Vitamin K Fact Sheet for Health Professionals

Generated August 27, 2026

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