The Benefits and Uses of Vitamin K

What You Need to Know About Vitamin K

Farm worker inspecting organic kale leaves
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Vitamin K is a nutrient that is necessary for blood clotting. Found in a number of vegetables such as dark leafy green vegetables, vitamin K is also available in supplement form or as a cream. Additionally, vitamin K is produced by the bacteria lining your gastrointestinal tract.

Uses for Vitamin K

Vitamin K is typically used to treat blood clotting problems and vitamin K deficiency. Vitamin K supplements are also purported to promote bone formation and protect against bone diseases like osteoporosis. In addition, some people take vitamin K to alleviate itching caused by biliary cirrhosis (a liver disease).

The Benefits of Vitamin K

Currently, there is enough scientific evidence to support the use of vitamin K for any condition apart from vitamin K deficiency and certain bleeding or blood clotting problems, according to the National Institutes of Health (NIH).

However, some studies suggest that vitamin K shows promise for the prevention or treatment of other health problems. Here's a look at some key findings:

Bone Health

Low vitamin K levels may be associated with low bone mineral density, according to a 2015 study published in the Journal of Clinical Biochemistry and Nutrition. The study's authors found that women with higher vitamin K intake had higher bone mineral density in the leg and low back compared to women with the lowest intake of vitamin K.

In a clinical trial comparing treatment with vitamin K and the medication risedronate to risedronate alone, researchers didn't find vitamin K plus medication more effective in preventing fractures than the medication alone.

Heart Disease

Observational studies and preliminary findings from animal-based studies have suggested a benefit of diets rich in vitamin K, studies involving supplements have not shown the same positive effects. For instance, in a report published in the Cochrane Database of Systematic Reviews in 2015, researchers analyzed previously published trials of vitamin K supplementation for three months or longer. Only one small trial met the researchers' quality criteria. The study, which was short-term and conducted on healthy adults, found no effects for vitamin K on blood pressure or blood lipid levels.

Foods High in Vitamin K

Leafy green vegetables are a top source of vitamin K. In fact, eating just one serving (i.e., a half-cup) of any of the following foods provides more than double your daily requirement for vitamin K:

  • kale
  • spinach
  • turnip greens
  • collard greens
  • Swiss chard
  • parsley
  • mustard greens

Brussel sprouts, broccoli, and romaine lettuce are also rich in vitamin K.

Forms of Vitamin K

Vitamin K1 (also known as phylloquinone) is the natural form of vitamin K found in plants. However, phytonadione (the synthetic version of phylloquinone) is commonly referred to as "vitamin K1" on supplement labels. Vitamin K is also available in other forms, including vitamin K2 (menaquinone) and vitamin K3 (menaphthone or menadione).

According to the NIH, vitamin K1 is less toxic, faster-acting, stronger, and more effective for certain conditions than other forms of vitamin K. Still, some research suggests that intake of vitamin K2 may offer certain health benefits, such as increased protection against heart disease.

Currently, the U.S. Food and Drug Administration prohibits the sale of vitamin K3 in dietary supplements. Injectable vitamin K3 is sometimes used in medical treatments, but there's evidence that these injectable formulas may cause allergic reactions and toxic effects.

Vitamin K is widely available in creams said to treat various skin conditions. Proponents claim that applying vitamin K cream to the skin can remove varicose veins, dark circles under the eyes, bruises, scars, and stretch marks, as well as treat rosacea and speed up the healing of wounds and burns. In most cases, vitamin K creams also contain other natural substances (such as herbal extracts and plant oils).


A very rare condition, vitamin K deficiency occurs when the body can't properly absorb vitamin K from the intestinal tract. This problem may be caused by certain diseases (including cystic fibrosis, celiac disease, and Crohn's disease), long-term use of antibiotics or blood-thinning medications, or treatment with hemodialysis. Signs and symptoms of vitamin K deficiency include excessive bleeding and bruising.

Side Effects

Taking high amounts of vitamin K in supplements may be harmful to pregnant and breastfeeding women, patients receiving dialysis treatments due to kidney disease, and people with clotting problems caused by severe liver disease. In addition, vitamin K may interact with certain supplements (including coenzyme Q10, vitamin E). You can get additional tips on using supplements here.

Using Vitamin K for Health

While vitamin K may help with certain health problems, self-treating a condition with vitamin K and avoiding standard care may have serious health consequences. Before you begin using vitamin K, talk to your doctor to determine a safe and effective dosage. Self-treating a condition and avoiding or delaying standard care may have serious consequences.

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