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Vitamin K is a group of vitamins found in some green vegetables. Vitamins K1 (phytonadione) and K2 (menaquinone) are commonly available as supplements.
Vitamin K is an essential vitamin needed by the body for blood clotting, bone building, and other important processes. It's found in leafy green vegetables, broccoli, and Brussels sprouts. The name vitamin K comes from the German word "Koagulationsvitamin."
People commonly use vitamin K for blood clotting problems or for reversing the blood thinning effects of warfarin. It is also used for osteoporosis, athletic performance, breast cancer, diabetes, and many other conditions, but there is no good scientific evidence to support most of these other uses.
- Hemorrhagic disease. Oral or intramuscular vitamin K1 is effective for preventing hemorrhagic disease in newborns.
Login for details - Hypoprothrombinemia. Oral or parenteral vitamin K1 is effective for treating and preventing hypoprothrombinemia.
Login for details - Vitamin K-dependent clotting factors deficiency (VKCFD). Oral and intravenous vitamin K1 is the primary treatment for VKCFD.
Login for details - Warfarin anticoagulation. Oral and intravenous vitamin K1 reverse warfarin-related excessive anticoagulation. Evidence for the use of oral vitamin K1 in patients with an unstable INR is conflicting.
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- Osteoporosis. Oral vitamin K might reduce the risk of fractures and bone loss in patients with osteoporosis. However, it may not be beneficial in patients at risk for developing osteoporosis.
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- Intraventricular hemorrhage. Oral vitamin K does not reduce the risk of periventricular hemorrhage in preterm infants.
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- Athletic performance. It is unclear if oral vitamin K2 improves athletic performance.
Login for details - Beta-thalassemia. Oral vitamin K2 has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Breast cancer. It is unclear if dietary intake of vitamin K2 reduces the risk of breast cancer.
Login for details - Cancer. It is unclear if dietary intake of vitamin K reduces the risk of cancer or cancer-related mortality.
Login for details - Cardiovascular disease (CVD). It is unclear if dietary or supplemental vitamin K reduces the risk of CVD events.
Login for details - Cataracts. It is unclear if dietary vitamin K reduces the risk of cataracts in older adults.
Login for details - Colorectal cancer. It is unclear if dietary intake of vitamin K2 reduces the risk of colorectal cancer.
Login for details - Cystic fibrosis. It is unclear if oral vitamin K improves coagulopathy in patients with cystic fibrosis.
Login for details - Depression. It is unclear if dietary intake of vitamin K reduces depression.
Login for details - Diabetes. It is unclear if oral vitamin K1 improves glycemic control in patients with diabetes.
Login for details - EGFR inhibitor-induced acneiform rash. It is unclear if topical vitamin K is beneficial for the treatment or prevention of acneiform rash caused by EGFR inhibitors.
Login for details - Liver cancer. Small clinical studies suggests that vitamin K2 reduces mortality and the risk for hepatocellular carcinoma recurrence.
Login for details - Liver disease. It is unclear if dietary intake of vitamin K reduces the risk of liver disease.
Login for details - Lung cancer. It is unclear if dietary intake of vitamin K reduces the risk of lung cancer.
Login for details - Multiple sclerosis (MS). It is unclear if topical vitamin K reduces cutaneous adverse effects of MS treatment.
Login for details - Overall mortality. It is unclear if dietary intake of vitamin K reduces the risk of prostate cancer.
Login for details - Polycystic ovary syndrome (PCOS). It is unclear if vitamin K improves PCOS symptoms.
Login for details - Prostate cancer. It is unclear if dietary intake of vitamin K reduces the risk of prostate cancer.
Login for details - Rheumatoid arthritis (RA). It is unclear if oral vitamin K improves RA symptoms.
Login for details - Rosacea. Login for details
- Stroke. It is unclear if dietary intake of vitamin K1 reduces the risk of stroke.
Login for details - Wound healing. Login for details
When taken by mouth: The two forms of vitamin K (vitamin K1 and vitamin K2) are likely safe when taken appropriately. Vitamin K1 10 mg daily and vitamin K2 45 mg daily have been safely used for up to 2 years. It's usually well-tolerated, but some people may have an upset stomach or diarrhea.
When applied to the skin: Vitamin K1 is possibly safe for most people when applied as a cream that contains 0.1% vitamin K1.
Special Precautions & Warnings:
Pregnancy and breast-feeding: Vitamin K is likely safe when taken in recommended amounts of 90 mcg daily for those over 19 years old. Don't use higher amounts without the advice of a healthcare professional.Children: Vitamin K1 is likely safe when taken by mouth appropriately.
Kidney disease: Too much vitamin K can be harmful if you are receiving dialysis treatments due to kidney disease.
Liver disease: Vitamin K is not effective for treating clotting problems caused by severe liver disease. In fact, high doses of vitamin K can make clotting problems worse in these people.
Reduced bile secretion: People with decreased bile secretion might not absorb vitamin K supplements very well. People with this condition might need to take supplemental bile salts along with vitamin K to improve absorption.
Warfarin (Coumadin)
Interaction Rating=Major Do not take this combination.
Vitamin K is used by the body to help blood clot. Warfarin (Coumadin) is used to slow blood clotting. By helping the blood clot, vitamin K might decrease the effectiveness of warfarin (Coumadin). Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.
Coenzyme Q10: Vitamin K helps the blood to clot. Coenzyme Q10 can have some of the same effects as vitamin K. Taking coenzyme Q10 and vitamin K together can increase blood clotting. This can be a problem for people who are taking blood thinners. Coenzyme Q10 plus vitamin K might overwhelm the effects of blood thinners.
Tiratricol: There is some concern that tiratricol might interfere with the effects of vitamin K. But it's not clear if this is a big concern.
Vitamin A: There is some concern that high doses of vitamin A might interfere with the effects of vitamin K. But it's not clear if this is a big concern.
Vitamin E: High doses of vitamin E (e.g. greater than 800 units/day) can reduce the effects of vitamin K for blood clotting. In people who take warfarin, a blood thinner, or in people who have low vitamin K intakes, high doses of vitamin E can increase the risk of bleeding.
There are no known interactions with foods.
Vitamin K is an essential vitamin. It is found in leafy green vegetables, broccoli, and Brussels sprouts.
It's recommended that males over 19 years old consume 120 mcg daily, and females over 19 years old consume 90 mcg daily. While pregnant and breast-feeding, 90 mcg should be consumed daily. Recommended amounts for children depend on age. Speak with a healthcare provider to find out what dose might be best for a specific condition.
2-methyl-1,4-naphthoquinone, 2-methyl-3-phytyl-1,4-naphthoquinone, 4-Amino-2-Methyl-1-Naphthol, Fat-Soluble Vitamin, Menadiol, Menadiol Acetate, Menadiol Diacetate, Menadiol Sodium Diphosphate, Menadiol Sodium Phosphate, Menadiolum Solubile Methynaphthohydroquinone, Menadione, Ménadione, Menadione Sodium Bisulfite, Menaquinone, Ménaquinone, Menatetrenone, Menatétrenone, Phytonadione, Methylphytyl Naphthoquinone, Phylloquinone, Phytomenadione, Vitamina K, Vitamine K, Vitamine Liposoluble, Vitamine Soluble dans les Graisses.
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