Vitamin K1: Benefits, Side Effects & Dosage


What is Vitamin K1?

Vitamin K refers to a group of fat-soluble vitamins with a similar molecular structure. Vitamin K1 and vitamin K2 are the two main forms found in the human diet. Also known as phylloquinone, vitamin K1 is mainly found in plant foods like leafy greens and several other vegetables. Several vitamin K1-rich foods include spinach, broccoli, kale and turnip greens. It accounts for about 75-90 percent of all vitamin K ingested by humans (x).

Vitamin K1 is known for its crucial role in blood clotting by activating certain coagulation factors. It activates proteins that play important roles in blood clotting. Deficiency in vitamin K1 is rare in adults, but very common in newborn infants. This deficiency increases the risk of uncontrolled bleeding. Though vitamin K1 deficiencies are rare, those with diseases like celiac disease and Crohn’s disease that affect absorption in the digestive tract, those that are severely malnourished, heavy drinkers and those taking medications that interfere with vitamin K absorption are at higher risk.

Are Vitamin K and Potassium the Same Thing?

Vitamin K is often confused with potassium. Although potassium is represented by letter K on the periodic table of elements, it’s not the same as vitamin K. Potassium is an electrolyte required by the body to conduct electricity. It also couples with sodium to help the water maintain water balance. Vitamin K, on the other hand, is a nutrient that the body stores in the liver and fatty tissue, and its main function is to maintain blood coagulation.

Potassium is present in veggies and fruits like plums, bananas and potatoes. Increased consumption of potassium allows the body to excrete more sodium, reducing the risk of suffering from high blood pressure. Just like vitamin K, potassium helps increase bone density. It is also an important mineral that helps reduce the risk of kidney stones and stroke.

Vitamin K1 Benefits

Bone Health

Vitamin K1 is an important nutrient in the maintenance of healthy bones. It is as important to bone health as calcium. Vitamin K1 couples with calcium to develop strong bones. It is needed for the synthesis of osteocalcin, which is the bone protein matrix where calcium crystallizes. Lack of osteocalcin would cause bones to break easily because there would be no bone structure and order to bone tissue. Vitamin K also helps in fracture healing (x, x).


Vitamin K1 has an anti-inflammatory, which can help prevent osteoporosis, obesity and diabetes. Individuals who consume lots of vitamin K1-rich foods have lower levels of the inflammatory biometrics associated with these diseases. A study known as The Predimed Study showed that people with a vitamin K1-rich diet had much lower levels of several risk factors like the hunger hormone ghrelin, which increases appetite and makes people eat more, and the tumor necrosis factor (cytokines that increase inflammation) (x).


Studies evaluating the health benefits of vitamin K1 suggests that it could benefit blood clotting. In fact, a number of proteins involved in blood clotting rely on vitamin K1 to get their job done. People who take medications like warfarin that prevent blood from clotting easily should take them consistently due to their powerful effects on blood clotting. Vitamin K1 helps to reverse the effects that result from too much intake of blood thinning medications and to prevent clotting problems in infant newborns who have vitamin K deficiency. Doctors can also administer vitamin K via injection to patients to treat clotting problems (x).

Vitamin K for Skin

Vitamin K can function as a powerful antioxidant, which can promote healthy and beautiful skin by preventing the harmful effects caused by free radicals. Exposure to harmful sun rays, smoke and environmental pollution are some of the common causes of free radicals.

Vitamin K is also important in maintaining a glowing and soft complexion due to its involvement in cell growth and tissue renewal. It also helps to get rid of the dry skin cells on the outer skin layer and replace them with new ones, giving it a young-looking complexion.

Moreover, vitamin K helps to reduce visible signs of skin aging. Wrinkles and fine lines on the skin result from reduced collagen production. Collagen is a protein responsible for maintaining the skin’s ability to stretch. Vitamin K protects collagen and ensures that its production is maintained. This gives the skin a smooth and youthful appearance.

One study conducted on the benefits of vitamin K to the skin showed that it is important in maintaining capillary integrity and elasticity of the skin. All these are factors necessary for healthy skin (x).

Vitamin K also helps the skin to fight conditions like scars, stretch marks, spider veins, dark spots and stubborn circles around the eye.

Other Benefits and Uses

Supports Heart Health

Vitamin K can lower the risk of coronary calcification, which happens when a layer of plaque develops on the inner lining of the coronary arteries. It does this by activating a protein that prevents calcium from building on the arteries. The plaque reduces the arterial elasticity (x). It also decreases the risk of deaths that result from coronary heart disease. These benefits are mostly associated with vitamin K2, but supplementing with vitamin K1 might help prevent the progression of coronary calcification.

Cognitive Health

A study showed that vitamin K proteins are crucial for the brain. High blood levels of vitamin K may be beneficial by improving episodic memory in older adults (x). Some evidence also suggests that vitamin K’s anti-inflammatory activity can help protect the brain against oxidative stress triggered by free radical damage. Oxidative stress can cause damage to brain cells and cause diseases like Alzheimer’s disease and cancer (x).

Benefits of Vitamin K1

Vitamin K1 Side Effects

While vitamin K1 does offer a variety of benefits, there are still a few potential side effects to keep in mind.

  • Flushing of the face (x) — this is a temporary side effect that doesn’t require medical attention unless it advances or becomes bothersome
  • Dizziness
  • Chest pain

Other Side Effects and Warnings

  • Hyperbilirubinemia results from the breakdown of red blood cells — infants are not able to get rid of the bilirubin easily, and it builds up in their blood and other tissues, causing the baby to have yellowing on the skin or eyes due to the bilirubin’s coloring (x, x)
  • Hypersensitivity reactions
  • Increased perspiration
  • Shortness of breath
  • Discoloration on the lips, palms of the hands and fingernails
  • Profuse sweating
  • Decreased blood pressure
  • Rapid or weak pulse
  • Bleeding at the injection site

Risks Associated with Vitamin K

Anticonvulsants can increase the risk of vitamin K deficiency in newborns and infants if taken during pregnancy or while breastfeeding.

Blood thinners also may interfere with blood flow to the heart and brain. These blood thinners decrease vitamin K’s clotting ability. Sudden interference with vitamin K intake may alter the outcome of these medications. However, one can avoid these problems by consuming vitamin K consistently.

Cholesterol-lowering drugs can interfere with dietary fat absorption. Individuals taking these drugs are at a higher risk of deficiency. People taking such medications should seek advice from a health professional about their vitamin K intake.

Vitamin K Deficiency Symptoms

Real vitamin K deficiency is rare in healthy adults. It mainly occurs in individuals with extreme malnutrition or those taking medications like warfarin. Symptoms of vitamin K deficiency include:

  • Excessive bleeding may fail to stop easily — vitamin K deficiency means wounds, surgical and injection sites and bruises will not heal quickly due to a defective blood clotting process
  • Heavy menstrual periods
  • Easy Bruising
  • Blood in stool and urine
  • Nose bleeding and bleeding from the gums
  • Bleeding from the gut
  • Excessive bleeding in mucous membrane
  • Tiny blood clots under the nails

Vitamin K1 for Dogs

Phytonadione (vitamin K1) can treat dogs that have been poisoned with bishydroxycoumarin or warfarin. It treats poisoning from certain mouse and rat poisons. Such poisoning could cause bleeding disorders in animals. Vitamin K1, however, can help stop the bleeding.

Vitamin K therapy is used in such cases due to vitamin K’s clotting factor properties. A blood CBC (Complete Blood Count) is done to establish the poison and level in the bloodstream. The therapy begins with a parenteral injection dose of vitamin K. Vitamin K pills will then be administered to the dog for up to six weeks daily.

Foods Containing Vitamin K1

Vitamin K1 is present in a variety of foods, including some leafy greens and numerous other vegetables.

  • Mustard greens
  • Spinach
  • Cucumbers
  • Cabbage
  • Cauliflower
  • Turnip greens
  • Brussels sprouts
  • Swiss chard
  • Dandelion greens

Vitamin K1 Dosage and Instructions

As a dietary supplement, take 10 milligrams daily of vitamin K1 1% powder, or as directed by a physician. A milligram scale is necessary to accurately measure this product. Of course, be sure to consult your doctor before adding any supplement to your regimen.

The Bottom Line

Vitamin K1 is beneficial for blood clotting, bone health, calcium absorption, brain and cardiac health. Signs and symptoms of vitamin K1 deficiency include bloody urine and stool, heavy periods, excessive bleeding and bruising. Vitamin K deficiency may result from certain medications like blood thinners, poor dietary intake, having health conditions that interfere with absorption and poor gut health. Sources of vitamin K1 are foods such as green veggies like kale, spinach and broccoli. For optimal health, try to increase vitamin K1-rich food sources in your diet. You can do this by including one green vegetable daily and include fermented foods into your diet.

About the author

Dennis Njeru

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