Daily Vitamin K Intake: How Much Vitamin K Do You Need?

By The DRI Calculator Team  |  Published: August 11, 2026  |  Updated: August 11, 2026  |  9 min read

Your daily vitamin K intake should be 120 micrograms for men and 90 for women, and most people meet it easily from leafy greens. Vitamin K is best known for one essential job, helping your blood clot, but it comes in two different families, K1 and K2, that get marketed very differently, and that is where most of the confusion begins. There is also one warning that genuinely matters, the interaction with blood-thinning medication like warfarin, and it is almost always explained badly. The real message there is not to avoid vitamin K, but to keep your intake steady. This guide covers the numbers by age, the K1 and K2 split in plain terms, the best foods, and an honest look at the supplement claims.

What Your Daily Vitamin K Intake Should Be

Vitamin K is set as an Adequate Intake rather than a full Recommended Dietary Allowance, because the evidence was not strong enough to establish an RDA. For adults the AI is 120 micrograms a day for men and 90 micrograms for women. Our guide to what DRI is explains how an Adequate Intake differs from an RDA and where it sits among the reference values.

One point matters before going further: this single target covers the whole vitamin K family, both K1 and K2 together. Health authorities did not set separate numbers for each form, which is a large part of why supplement labels, which single out one form, cause so much confusion. Vitamin K is fat-soluble and the body keeps only a small store, so a regular dietary supply matters, though as the next sections show, deficiency is uncommon.

Daily Vitamin K Intake by Age & Sex (Full Chart)

Vitamin K needs rise through childhood and settle into the adult figures in the late teens. Unlike many nutrients, the targets do not rise for pregnancy or breastfeeding, staying at the standard adult figure for women.

How much vitamin K do you need per day?

Adult men need 120 micrograms of vitamin K a day and adult women need 90 micrograms, set as Adequate Intake values. These figures stay the same during pregnancy and breastfeeding. Teenagers aged 14 to 18 need 75 micrograms, and younger children need between 30 and 60 micrograms depending on age.

K1 vs K2: What's the Difference?

Vitamin K is not one substance but two families, and understanding the split explains almost everything about the supplement aisle.

Vitamin K1 (phylloquinone) is the form found in plants, especially leafy green vegetables, and it makes up most of the vitamin K in a typical diet. Its main role is in blood clotting. Vitamin K2 (menaquinones, often labelled MK-4 or MK-7) is found in fermented foods and some animal products, and is also made by bacteria in the gut. K2 is the form marketed for bone and heart health. The two are related but not interchangeable microgram for microgram, and the official Adequate Intake was set mainly around the K1 needed for healthy clotting.

Best Food Sources of Vitamin K

The great majority of dietary vitamin K comes from green vegetables as K1, and a single serving of leafy greens often provides several times the daily target. K2 appears in smaller amounts in fermented and animal foods.

A single serving of kale or collard greens provides several days' worth of vitamin K on its own, which is why deficiency is rare for anyone eating vegetables regularly. It is also why a sudden change in how many greens you eat is the key issue for people on blood thinners, as the next section explains.

What Vitamin K Actually Does

Vitamin K has one settled, essential role and one area of active debate. The settled role is blood clotting: vitamin K is required to make several of the proteins that allow blood to clot, which is why the name comes from the German word for coagulation, and why a deficiency causes bleeding problems. This function is basic, well-established physiology.

The area of debate is bone and heart health. Vitamin K, especially K2, helps activate proteins involved in directing calcium into bones and away from artery walls, and this is the basis for the bone and cardiovascular claims made for K2 supplements. The idea is biologically plausible and genuinely promising, but as the supplement section below explains, the marketing has moved well ahead of what the trials have actually shown.

The Warfarin Rule: Consistency, Not Avoidance

This is the single most important thing to understand about vitamin K, and it is the point most often explained badly. Warfarin, a common blood-thinning medication, works precisely by blocking vitamin K, since vitamin K drives clotting and warfarin is meant to slow it. That direct opposition is why the two interact.

Do You Need a Vitamin K2 Supplement?

Walk through any supplement aisle and K2, usually as MK-7, is heavily promoted for bone and heart health, often paired with vitamin D. The honest position is that this is an area where marketing has outrun the evidence.

The clotting role of vitamin K is not in question. The bone and artery claims for K2 rest on a smaller and more mixed set of trials, several of which were industry-funded and conducted in specific groups such as postmenopausal women, so the benefit is not established for the general population, for men, or for younger adults. There is no separate official recommendation for K2, and no established upper limit for vitamin K overall. For most people eating vegetables regularly, a K2 supplement is not a proven need. If you are considering one for a specific reason such as bone density, it is worth discussing with a doctor rather than following supplement marketing, particularly if you take any blood-thinning medication.

Signs of Low Vitamin K

Vitamin K deficiency is uncommon in healthy adults because the vitamin is plentiful in common foods and is also made by gut bacteria. When it does occur, the hallmark is impaired clotting, showing up as easy bruising, bleeding gums, blood in the urine or stool, or unusually heavy bleeding from small wounds. The groups most at risk are newborns, who are born with very low stores and are routinely given a vitamin K injection at birth to prevent a serious bleeding disorder, along with people who have conditions that impair fat absorption, such as celiac disease or cystic fibrosis, and those on long-term antibiotics that disrupt gut bacteria. Because the signs involve abnormal bleeding, they always warrant medical attention rather than self-treatment.

Who Needs to Watch Their Vitamin K

Most people simply need to eat vegetables regularly and never think about vitamin K. A few groups are exceptions. People on warfarin or similar blood thinners need the consistency described above and should coordinate with their doctor. Newborns are managed by standard medical care. People with fat-malabsorption conditions may absorb too little and need monitoring. Beyond those cases, the standard figures apply, and the differing needs of men and women across life are set out in our guides to the DRI for men and the DRI for women. Because vitamin K needs do not rise in pregnancy, the broader set of changes that do matter then is covered in our guide to the DRI for pregnancy.

How to Hit Your Daily Vitamin K Intake

For almost everyone, this is one of the easiest targets to meet. A single serving of leafy greens, kale, spinach, collards, broccoli, or Brussels sprouts, several times a week covers the requirement many times over, and because vitamin K is fat-soluble, eating those greens with a little oil or other fat improves absorption. A smaller contribution of K2 comes naturally from eggs, cheese, chicken, and fermented foods. Supplements are not necessary for most people, and anyone on a blood thinner should aim for a steady intake rather than either avoiding or loading up on greens.

The most useful starting point is your own number, since it depends on your age and sex. Your full nutrient targets, vitamin K included, take only a moment to calculate.

Frequently Asked Questions