Vitamin K2 explained: what it is and food sources
The NIH says K2 forms called menaquinones mainly come from bacteria and occur in animal-based and fermented foods. Daily adequate intakes for adults 19 years and older are 120 mcg for men and 90 mcg for women, for total vitamin K, not K2 alone. One product we reviewed lists vitamin K2, and its label prints 100 mcg per serving.
- What it is
- Vitamin
- What adults need a day (ages 19 and older)
- 120 mcg for men, 90 mcg for women
- In the products we reviewed
- 1, its label prints the amount
What vitamin K2 is
- Vitamin K2 supplements use forms called MK-4 and MK-7.1
- Menaquinones mainly come from bacteria and occur in animal-based and fermented foods.1
- Bacteria in the human gut also make almost all forms of menaquinones.1
- Vitamin K is important for normal blood clotting and healthy bones.2
- Vitamin K is available alone or combined with nutrients such as calcium, magnesium and vitamin D.2
- Natto, a Japanese food made from fermented soybeans, contains high amounts of menaquinones.1
Foods that have it1
- Meat
- Dairy foods
- Eggs
How much vitamin K2 each product gives
Adults need 90 to 120 mcg a day
Before you take it
If you take medicines
- Warfarin (Coumadin), phenprocoumon, acenocoumarol and tioclomarol
- Vitamin K can have a serious and potentially dangerous interaction with these blood thinners.1
- Antibiotics, including cefoperazone (Cefobid)
- Antibiotics can destroy gut bacteria that make vitamin K. Cephalosporin antibiotics such as cefoperazone (Cefobid) might also interfere with vitamin K activity.1
- Cholestyramine (Questran) and colestipol (Colestid)
- These medicines can decrease how much vitamin K your body absorbs, especially with many years of use.2
Ask a doctor first
- If you take warfarin, keep your vitamin K intake from food and supplements about the same every day.2
- People who regularly take medicines should discuss their vitamin K status with their health care providers.1
These statements have not been evaluated by the FDA. A supplement is not a medicine.
The product we reviewed that lists vitamin K2
| Product | Form and serving | Vitamin K2 per serving | Our score | Price a bottle | Buy |
|---|---|---|---|---|---|
 BoostaroMen's health support | Capsules2 capsules | 100 mcg83% of daily need | Not ranked | $49 | Check price |
Questions people ask
What is vitamin K2 MK-7?
MK-7 is a form used in vitamin K2 supplements, according to the NIH. Vitamin K2 supplements also use a form called MK-4.
What foods contain vitamin K2?
Meat, dairy foods and eggs contain vitamin K2. The NIH says menaquinones mainly come from bacteria and occur in animal-based and fermented foods.
What fermented food is high in vitamin K2?
Natto contains high amounts of menaquinones, according to the NIH. It is a Japanese food made from fermented soybeans.
How much vitamin K2 should I take daily?
The adult adequate intake is for total vitamin K, not vitamin K2 separately. For adults 19 years and older, it is 120 mcg a day for men and 90 mcg a day for women.
What does vitamin K2 do for blood clotting?
The NIH says vitamin K is important for normal blood clotting.
Which products we reviewed contain vitamin K2?
Boostaro is the only product we reviewed that lists vitamin K2. Its label prints 100 mcg per serving of 2 capsules, with a daily value of 83%.
Sources
The products, amounts and prices come from each product's label and checkout, as its review shows them. AI drafts our pages from listed sources, figures are checked against them, and we have not tried the products.
- 1NIH Office of Dietary Supplements, vitaminK HealthProfessionalods.od.nih.gov/factsheetschecked
- 2NIH Office of Dietary Supplements, vitaminK Consumerods.od.nih.gov/factsheetschecked