Verified Supplement Data

Vitamin K2 Dosage: How Much MK-7 to Take (and with Vitamin D)

There is no official K2 dose. Most bottles give 100 mcg of MK-7; take it once a day with a meal. Trials tested 90 mcg a day over 1 year and 180 mcg a day over 3 years. If you take warfarin or a similar blood thinner, don’t take K2 unless the doctor who manages it says so.

By Erin Rose Updated October 5, 2026 How we score

How much, by situation

Find your situation. These amounts are for adults.

Source: the trials below and NIH’s vitamin K fact sheet.
Your situationHow muchNotes
Most adults who want K290 to 100 mcg of MK-7 a day is typicalMost bottles give 100 mcg. 90 mcg is the dose the 1-year trials tested; see the trial list for what each one measured. More
To match the 3-year bone trial180 mcg a dayTwo 100 mcg pills, or one 180 mcg pill. More
More than thatNo proven gainNo trial shows a higher dose works better for bones or arteries. More
On warfarin or a similar drugOnly if your doctor says soIn a small study, even 10 mcg a day changed the clotting test in some people. More
On apixaban, rivaroxaban, dabigatran or edoxabanTell your doctorThese drugs do not work through vitamin K. More
Taking it with vitamin DNo set ratioNo trial has tested a K2-to-D ratio. More

Best vitamin K2, all 17 we score

When and how to take it

Take it with a meal that has some fat. Vitamin K dissolves in fat and is absorbed with it (NIH). No trial has compared K2 taken with and without food.

The time of day likely matters little. MK-7 stays in the blood much longer than vitamin K1, so daily doses build up to steady levels (Schurgers 2007). In a small study, blood MK-7 did not follow a day-night rhythm (Du 2023). Pick a time you will remember.

What the bottles hold

Most bottles give 100 mcg of MK-7 a serving: 11 of the 17 K2 products we score.

MK-7 per serving on each label we score, read October 5, 2026. Blends also hold K1 or MK-4.
MK-7 a servingBrands
45 mcgLife Extension
90 mcgThorne, Jarrow Formulas
100 mcgNature Made, Nutricost, InnovixLabs, Horbaach, NatureWise, MaryRuth's, Sports Research, Bronson, Doctor's Best, Solgar, NOW Foods
180 mcgSports Research, Life Extension
300 mcgNOW Foods

What doses the trials used

K2 trials have used 10 to 720 mcg of MK-7 a day. Benefits were reported at 90, 180 and 360 mcg. Other trials at 360, 375 and 720 mcg found no benefit. Dose alone does not decide the result: the people, the length and what was measured all differ.

Figure 1. The daily K2 dose in each outcome trial
0 194.5 389 583.5 778 Zhang 2020: bone, 1 year less hip-neck bone loss in women after menopause; none in men 90 mcg Kurnatowska 2015: artery wall, 9 months slower artery-wall thickening in kidney disease; calcium not slowed 90 mcg Knapen 2013: bone, 3 years less bone loss at the spine and hip neck, not the whole hip 180 mcg Vossen 2026: heart arteries, 2 years slower new calcium build-up in people with heart disease 360 mcg Emaus 2010: bone, 1 year did not slow bone loss in women just past menopause 360 mcg Zwakenberg 2019: arteries, 6 months did not slow artery calcium in type 2 diabetes 360 mcg RenaKvit 2021: arteries, 2 years did not slow artery calcium build-up on dialysis 360 mcg Rønn 2021: bone, 3 years no effect on bone density or structure 375 mcg AVADEC 2022: heart valve, 2 years did not slow valve calcium build-up (with vitamin D) 720 mcg
Teal bars found a benefit; grey bars found none. 90 mcg is the lowest dose with a reported benefit. Source: PubMed 32060566, 26176325, 23525894, 42268593, 19937427, 31387121, 34476095, 33030563, 35465686.
Figure 1. The daily K2 dose in each outcome trial
ItemValue
Zhang 2020: bone, 1 year90 mcg
Kurnatowska 2015: artery wall, 9 months90 mcg
Knapen 2013: bone, 3 years180 mcg
Vossen 2026: heart arteries, 2 years360 mcg
Emaus 2010: bone, 1 year360 mcg
Zwakenberg 2019: arteries, 6 months360 mcg
RenaKvit 2021: arteries, 2 years360 mcg
Rønn 2021: bone, 3 years375 mcg
AVADEC 2022: heart valve, 2 years720 mcg

The 3-year trial gave 180 mcg of MK-7 a day to 244 healthy women after menopause and slowed bone loss at the spine and hip neck, but not across the whole hip (Knapen 2013). The 1-year trial in China gave 90 mcg of K2 a day; it slowed bone loss at the hip neck in women after menopause, but not in men (Zhang 2020). In a 12-week trial of 10 to 360 mcg a day, doses around the European daily reference amount improved lab markers of vitamin K status (Theuwissen 2012). No trial shows a higher dose works better for bones or arteries. What K2 does, trial by trial.

If you take a blood thinner

Warfarin and similar drugs work against vitamin K. NIH says people who take them need to keep their vitamin K intake steady, because sudden changes can raise or lower the drug’s effect. In healthy volunteers on a warfarin-type drug, 45 mcg of MK-7 a day lowered INR, the clotting test these drugs are dosed by, by about 40%; even 10 mcg lowered it enough to matter in some people (Theuwissen 2013). The researchers advised people on these drugs to avoid MK-7 supplements. So don’t start, stop or change K2 unless the doctor who manages your blood thinner says so.

Newer blood thinners (apixaban, rivaroxaban, dabigatran, edoxaban) do not work through vitamin K (Rose 2018). Still tell your doctor about any supplement.

With vitamin D

No trial has tested a set ratio of K2 to vitamin D, so the K2 amount on a D3 + K2 bottle is the maker’s choice, not a tested dose. Whether adding K2 to vitamin D helps is not settled: in a 3-year trial, MK-7 added to vitamin D and calcium did not change bone density (Rønn 2021). Vitamin D with or without K2 covers the combinations.

MK-4 is dosed differently

MK-4 is another form of K2. In Japan, 45 mg (45,000 mcg) of MK-4 a day is used as an osteoporosis drug (NIH). At 420 mcg, MK-4 did not show up in the blood at all in a small study, while the same dose of MK-7 did (Sato 2012). So an MK-4 pill in micrograms is not the same as MK-7 in micrograms. MK-7 vs MK-4.

How much vitamin K adults need overall: 90 mcg a day for women and 120 mcg for men, from food and supplements together; most U.S. diets have enough (NIH). That target counts K1 and K2 together. K1 vs K2.

Questions

How much K2 should I take a day?

There is no official K2 dose. Most bottles give 100 mcg of MK-7, and trials tested 90 mcg (1 year) and 180 mcg (3 years) a day. Take it with a meal. If you take warfarin, ask your doctor first.

Is 300 mcg of K2 too much?

No upper limit is set for vitamin K (NIH), and a US Pharmacopeia safety review found no serious risk from MK-7 supplements (Marles 2017). No trial has compared 300 mcg with 100 or 180 mcg. On warfarin, any amount matters.

When is the best time to take K2?

With a meal that has some fat, because vitamin K is absorbed with fat. The time of day likely matters little: in a small study, blood MK-7 did not follow a day-night rhythm, and it stays in the blood a long time.

Sources

  1. Zhang Y, et al. Effect of low-dose vitamin K2 supplementation on bone mineral density in middle-aged and elderly Chinese. Calcif Tissue Int. 2020. PubMed 32060566
  2. Kurnatowska I, et al. Effect of vitamin K2 on progression of atherosclerosis and vascular calcification in nondialyzed patients with chronic kidney disease stages 3-5. Pol Arch Med Wewn. 2015. PubMed 26176325
  3. Knapen MH, et al. Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporos Int. 2013. PubMed 23525894
  4. Vossen LM, et al. Two years of menaquinone-7 supplementation and coronary artery calcification. JAMA Cardiol. 2026. PubMed 42268593
  5. Emaus N, et al. Vitamin K2 supplementation does not influence bone loss in early menopausal women: a randomised double-blind placebo-controlled trial. Osteoporos Int. 2010. PubMed 19937427
  6. Zwakenberg SR, et al. The effect of menaquinone-7 supplementation on vascular calcification in patients with diabetes. Am J Clin Nutr. 2019. PubMed 31387121
  7. Levy-Schousboe K, et al. Vitamin K supplementation and arterial calcification in dialysis (RenaKvit). Clin Kidney J. 2021. PubMed 34476095
  8. Rønn SH, et al. The effect of vitamin MK-7 on bone mineral density and microarchitecture in postmenopausal women with osteopenia. Osteoporos Int. 2021. PubMed 33030563
  9. Diederichsen ACP, et al. Vitamin K2 and D in patients with aortic valve calcification (AVADEC). Circulation. 2022. PubMed 35465686
  10. Theuwissen E, et al. Low-dose menaquinone-7 supplementation improved extra-hepatic vitamin K status. Br J Nutr. 2012. PubMed 22289649
  11. Theuwissen E, et al. Effect of low-dose supplements of menaquinone-7 on the stability of oral anticoagulant treatment. J Thromb Haemost. 2013. PubMed 23530987
  12. Rose DK, Bar B. Direct oral anticoagulant agents: pharmacologic profile, indications, coagulation monitoring, and reversal agents. J Stroke Cerebrovasc Dis. 2018. PubMed 29753603
  13. Schurgers LJ, et al. Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood. 2007. PubMed 17158229
  14. Du F, et al. The study of bioavailability and endogenous circadian rhythm of menaquinone-7. Br J Nutr. 2023. PubMed 37132123
  15. Marles RJ, et al. US Pharmacopeial Convention safety evaluation of menaquinone-7, a form of vitamin K. Nutr Rev. 2017. PubMed 28838081
  16. Sato T, Schurgers LJ, Uenishi K. Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women. Nutr J. 2012. PubMed 23140417
  17. NIH Office of Dietary Supplements. Vitamin K fact sheet for health professionals (updated March 29, 2021; read October 5, 2026).

This page is for information. It is not medical advice.