Vitamin K1
Vitamin ·Exploratory record · not publication-reviewed ·Updated July 13, 2026
The primary form of vitamin K found in plants, essential for blood clotting. Also supports bone health to a lesser extent than K2.
Exploratory record, not a reviewed medical publication.
See the editorial and medical-review policies for the publication gate.
This generated database record has not completed a claim-level review by a qualified human medical reviewer. Bibliography links and evidence labels are not approval. The page remains available for reference and is excluded from search indexing.
What the research says.
A quick, data-only summary. The full evidence, dosing, and sources are below.
Vitamin K1 is a vitamin most often used for blood clotting, bone health, wound healing. NutriStack rates the overall evidence as strong. A typical adult dose is 90–120 mcg daily, commonly taken as phylloquinone from food or supplements. This profile indexes 22 sources.
The bottom line
Evidence rating strong. Most-documented uses: blood clotting, bone health, wound healing. 22 sources indexed (1999–2025), with 0 interaction records on file.
How it works, mechanistically.
Core mechanism
Serves as a cofactor for gamma-glutamyl carboxylase, which activates clotting factors II (prothrombin), VII, IX, and X in the coagulation cascade.
Dosing & protocol.
What it actually costs.
Real-world pricing across three quality tiers. Assumes Phylloquinone.
Assumes 90-120 mcg/day. Vendor basis: NOW/iHerb, Vitacost, Life Extension, and Amazon marketplace; standalone K1 remains inexpensive. Updated 2026-05-28.
The same dose, as food.
How much you'd eat to match a supplemental dose.
Leafy greens are the dominant food source of K1.
Food can easily cover this unless greens intake is extremely low.
Full safety detail.
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Meta-analyses & systematic reviews
7- 1Effects of vitamin K supplementation on bone mineral density at different sites and bone metabolism in the middle-aged and elderly populationSource linkedPMIDGao Y, Hu Y, Liu Q et al. · Bone Joint Res · 2024
- 2Vitamin K supplementation and vascular calcification: a systematic review and meta-analysis of randomized controlled trialsSource linkedPMIDXu Q, Zhang Y, Liu S et al. · Front Nutr · 2023
- 3Effect of Vitamin K on Bone Mineral Density and Fracture Risk in Adults: Systematic Review and Meta-AnalysisPMIDMott A et al. · Nutrients · 2022
Vitamin K decreases general fracture risk (OR 0.42 vertebral, OR 0.44 clinical); can be an option to counter bone loss disorders
- 4Vitamin K supplementation for the primary prevention of osteoporotic fractures: a systematic review and meta-analysisSource linkedPMIDMott A, Bradley T, Wright K et al. · Arch Osteoporos · 2019
- 5Vitamin K intake and the risk of fractures: A meta-analysisPMIDHao G et al. · Medicine (Baltimore) · 2017
Four cohort studies and one nested case-control study (1,114 fracture cases, 80,982 participants) examined vitamin K1 intake and fracture risk
- 6Vitamin K and the prevention of fractures: systematic review and meta-analysis of randomized controlled trialsPMIDCockayne S et al. · Arch Intern Med · 2006
Pooling 7 trials: OR 0.40 for vertebral fractures, OR 0.23 for hip fractures, OR 0.19 for all nonvertebral fractures favoring vitamin K
- 7Treatment of excessive anticoagulation with phytonadione (vitamin K): a meta-analysisPMIDDezee KJ, Shimeall WT, Douglas KM et al. · Archives of internal medicine · 2006
Dezee KJ, Shimeall WT, Douglas KM et al.. Treatment of excessive anticoagulation with phytonadione (vitamin K): a meta-analysis. Archives of internal medicine. 2006
Randomized controlled trials
6- 8Effect of vitamin K1 supplementation on coronary calcifications in hemodialysis patients: a randomized controlled trialPMIDMacias-Cervantes HE, Ocampo-Apolonio MA, Guardado-Mendoza R et al. · Journal of nephrology · 2025
Macias-Cervantes HE, Ocampo-Apolonio MA, Guardado-Mendoza R et al.. Effect of vitamin K1 supplementation on coronary calcifications in hemodialysis patients: a randomized controlled trial. Journal of nephrology. 2025
- 9Vitamin K1 and progression of cardiovascular calcifications in hemodialysis patients: the VitaVasK randomized controlled trialPMIDSaritas T, Reinartz S, Krüger T et al. · Clinical kidney journal · 2022
Saritas T, Reinartz S, Krüger T et al.. Vitamin K1 and progression of cardiovascular calcifications in hemodialysis patients: the VitaVasK randomized controlled trial. Clinical kidney journal. 2022
- 10Effect of vitamin K supplementation on bone loss in elderly men and womenSource linkedPMIDBooth SL, Dallal G, Shea MK et al. · J Clin Endocrinol Metab · 2008
- 11The effect of vitamin K on warfarin stability in patients on long-term anticoagulation therapySource linkedPMIDSconce E, Avery P, Wynne H, Kamali F · J Thromb Haemost · 2007
- 12Comparison of oral vs intravenous phytonadione (vitamin K1) in patients with excessive anticoagulation: a prospective randomized controlled studyPMIDLubetsky A, Yonath H, Olchovsky D et al. · Archives of internal medicine · 2003
Lubetsky A, Yonath H, Olchovsky D et al.. Comparison of oral vs intravenous phytonadione (vitamin K1) in patients with excessive anticoagulation: a prospective randomized controlled study. Archives of internal medicine. 2003
- 13Randomized, placebo-controlled trial of oral phytonadione for excessive anticoagulationPMIDPatel RJ, Witt DM, Saseen JJ et al. · Pharmacotherapy · 2000
Patel RJ, Witt DM, Saseen JJ et al.. Randomized, placebo-controlled trial of oral phytonadione for excessive anticoagulation. Pharmacotherapy. 2000
Reviews & position papers
8- 14Supplementation of Vitamin K1 in Dogs With Chronic EnteropathyPMIDSmith JM, Smith CK, Zhu X et al. · Journal of veterinary internal medicine · 2025
Smith JM, Smith CK, Zhu X et al.. Supplementation of Vitamin K1 in Dogs With Chronic Enteropathy. Journal of veterinary internal medicine. 2025
- 15Vitamin K - a scoping review for Nordic Nutrition Recommendations 2023Source linkedPMIDHarshman SG, Finnan EG, Barger KJ et al. · Food Nutr Res · 2023
- 16Safety and efficacy of an additive consisting of synthetic vitamin K(1) (phytomenadione) for horses (JARAZ Enterprises GmbH & Co. KG)PMIDEFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), Bampidis V, Azimonti G et al. · EFSA journal. European Food Safety Authority · 2021
EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), Bampidis V, Azimonti G et al.. Safety and efficacy of an additive consisting of synthetic vitamin K(1) (phytomenadione) for horses (JARAZ Enterprises GmbH & Co. KG). EFSA journal. European Food Safety Authority. 2021
- 17Vitamin K Nutrition and Bone HealthPMIDCapozzi A et al. · Int J Endocrinol · 2020
Vitamin K required for osteocalcin carboxylation regulating bone mineral accretion; promotes osteoblast transition to osteocytes and limits osteoclastogenesis
- 18Interaction Between Dietary Vitamin K Intake and Anticoagulation by Vitamin K Antagonists: Is It Really True?: A Systematic ReviewPMIDVioli F et al. · Medicine (Baltimore) · 2016
Dietary vitamin K can decrease therapeutic effectiveness of warfarin; poor vitamin K status increases sensitivity to small changes in vitamin K intake
- 19Vitamin K and bone health in older adultsSource linkedPMIDHamidi MS, Cheung AM · J Clin Densitom · 2014
- 20Efficacy and safety of intravenous phytonadione (vitamin K1) in patients on long-term oral anticoagulant therapyPMIDShields RC, McBane RD, Kuiper JD et al. · Mayo Clinic proceedings · 2001
Shields RC, McBane RD, Kuiper JD et al.. Efficacy and safety of intravenous phytonadione (vitamin K1) in patients on long-term oral anticoagulant therapy. Mayo Clinic proceedings. 2001
- 21Oral versus intramuscular phytomenadione: safety and efficacy comparedPMIDvon Kries R · Drug safety · 1999
von Kries R. Oral versus intramuscular phytomenadione: safety and efficacy compared. Drug safety. 1999
Reference material
1- 22Ingold CJ, Sergent SR. Phytonadione (Vitamin K1). 2026Source linkedPMID
Common questions.
Quick answers about Vitamin K1, drawn from the data on this page.
What is Vitamin K1?
The primary form of vitamin K found in plants, essential for blood clotting. Also supports bone health to a lesser extent than K2.
What is Vitamin K1 used for?
Commonly cited benefits of Vitamin K1 include: Blood clotting; Bone health; Wound healing. NutriStack rates the overall evidence as strong.
What is a typical dose of Vitamin K1?
A typical adult dose of Vitamin K1 is 90–120 mcg daily. The commonly recommended form is Phylloquinone from food or supplements. These are general ranges, not personalized advice; confirm the right dose with a clinician.
What are the side effects of Vitamin K1?
Reported side effects include very low toxicity risk. This is educational information; check with a healthcare professional before use.
How strong is the evidence for Vitamin K1?
NutriStack rates this as Strong, meaning multiple high-quality meta-analyses or systematic reviews converge on the same finding. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.
Use this with your stack
Vitamin K1 in NutriStack.
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