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Vitamin K

Vitamin K

Best for

Build and maintain bone density

Large effect, needs confirmation for 26–156 weeks · 4 meta-analyses , n=7k

43 papers · 6 claims · 79 outcomes scored · 5 positive

Outcomes

What vitamin k actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect Evidence Dose Weeks Rank
Lower fracture risk in older adults Likely strong benefit
large 		5 meta-analyses n=91k Meta-analyzed 5–50 mg 104–208 wk #1/3
Build and maintain bone density Large effect, needs confirmation
large 		10 meta-analyses n=7.0k Meta-analyzed 0.0094–500 mg 26–156 wk #2/9
Raise vitamin K levels Likely strong benefit
large 		9 meta-analyses n=483 Meta-analyzed 2–45000 mcg 2–104 wk —
Strengthen bones by favoring buildup Promising early signal
moderate 		11 meta-analyses n=7.0k Meta-analyzed 0.0094–1500 mg 1–156 wk #1/5
Strengthen bone structure Likely modest benefit
small 		2 RCTs n=313 1–45 mg 78–156 wk #1/3
Protect bones while breastfeeding Doesn't appear to help
small 		5 meta-analyses n=5.0k Meta-analyzed 0.0094–500 mg 26–156 wk #1/4
Buy well

Recommended Vitamin K products

Real products that dose Vitamin K 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 K dosing vs. the studied range, a clean formulation (grade A–C), and independent brand-quality audits. Not sponsored.

Risk profile

Adverse events and known drug interactions

Safety events

Anaphylactic reaction severe
Hemolytic anemia severe
Hypoprothrombinemia severe
Hemorrhage severe
Pulmonary embolism severe
Deep vein thrombosis severe
nausea mild
irritability mild

Drug interactions

Warfarin major decreases effect
Orlistat moderate decreases concentration
Rifampicin moderate decreases concentration
Asciminib moderate additive
Ponatinib moderate additive
Antineoplastic Agents moderate unknown

Co-studied with

Supplements that share evidence with vitamin k

Sources

  1. 1. Vitamin K and the prevention of fractures: systematic review and meta-analysis of randomized controlled trials. (2006) ↑
  2. 2. Vitamin K2 supplementation improves hip bone geometry and bone strength indices in postmenopausal women. (2007) ↑
  3. 3. Vitamin K, circulating cytokines, and bone mineral density in older men and women. (2008) ↑
  4. 4. Vitamin K supplementation in postmenopausal women with osteopenia (ECKO trial): a randomized controlled trial. (2008) ↑
  5. 5. Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials. (2022) ↑
  6. 6. The additive effect of vitamin K supplementation and bisphosphonate on fracture risk in post-menopausal osteoporosis: a randomised placebo controlled trial. (2023) ↑
  7. 7. Habitual natto intake elevates serum MK-7 levels, enhances osteocalcin carboxylation, and supports bone density: a meta-analysis of Japanese evidence. (2025) ↑
  8. 8. Effects of vitamin K supplementation on bone mineral density at different sites and bone metabolism in the middle-aged and elderly population. (2024) ↑
  9. 9. The effect of menaquinone-7 supplementation on dp-ucMGP, PIVKAII, inflammatory markers, and body composition in type 2 diabetes patients: a randomized clinical trial. (2022) ↑
  10. 10. Vitamin K to prevent fractures in older women: systematic review and economic evaluation. (2009) ↑

Generated August 14, 2026

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