Verified Supplement Data

MK-7 vs MK-4 (2026): Which Vitamin K2 & How Much to Take?

By Erin Rose Updated October 5, 2026 How we score

For a daily K2 pill, choose MK-7. It stays in the blood much longer, so a small daily dose builds up; at 420 mcg, MK-4 did not show up in the blood at all. Most bottles give 100 mcg of MK-7; trials tested 90 to 360 mcg a day, and others went up to 720. MK-4’s bone trials mostly used 45 mg a day, a drug dose in Japan. We found no trial comparing the two forms on fractures.

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How much to take: our K2 dosage guide. Most bottles give 100 mcg of MK-7; a full dose by our count is 90 mcg or more. Every K2 we score, ranked: best vitamin K2.

The forms of vitamin K

Vitamin K comes as K1, from leafy greens, and K2, a family of forms named by the length of their side chain (NIH). MK-7 and MK-4 are the two K2 forms you will see on labels.

Sources: the PubMed abstracts listed below, our dosage guide’s trial list and NIH’s vitamin K fact sheet. This table as data.
FormIn the bloodOn labelsTrial doseWhat trials found
MK-7Menaquinone-7A very long time; daily doses build up to steady levelsMostly 100 mcg a pill (45 to 300 mcg)90, 180, 360 and up to 720 mcg a dayBenefits at 90 mcg (bone, 1 year), 180 mcg (bone, 3 years) and 360 mcg (heart-artery calcium, 2 years); other trials at 360, 375 and 720 mcg found no benefit
MK-4MenatetrenoneNot found in the blood at 420 mcg100 mcg to 15,000 mcg, often in blendsMostly 45 mg (45,000 mcg) a day, a prescription osteoporosis drug in JapanAn early review of Japanese trials found fewer fractures, but it included problematic trials; the largest trial (4,378 women) found no overall drop in spine fractures (it may have helped severe osteoporosis), and a Western trial found no change in bone density
K1PhylloquinoneShorter than MK-7; most goes to the liverAbout 100 mcg in K1 pills; 1,000 to 2,000 mcg in some blends1 to 5 mg a day in bone trials5 mg a day for 2 to 4 years did not change bone density; fewer had fractures, but the trial was not built to test that

Which one stays in the blood

MK-7 does. In a study of healthy Japanese women, one 420 mcg dose of MK-7 was absorbed and could be measured for 48 hours. The same dose of MK-4 could not be found in the blood at all, and 60 mcg of MK-4 a day for 7 days did not raise blood MK-4 either (Sato 2012).

Next to vitamin K1, MK-7 has a very long half-life, so daily doses build up to steadier, higher blood levels (Schurgers 2007). That is why a once-a-day pill in micrograms keeps MK-7 blood levels up.

MK-4 and fractures

Most MK-4 bone trials used 45 mg (45,000 mcg) a day, the dose used as an osteoporosis drug in Japan (NIH). A 2006 review of 7 Japanese MK-4 trials found fewer fractures (Cockayne 2006). In 2018, one of its authors published a caution to readers that the review included problematic trials (Torgerson 2018). The largest Japanese trial, in 4,378 women, found the 45 mg drug did not lower new spine fractures overall over 3 years; it may have helped women with severe osteoporosis (Inoue 2009). In North American women, a year of 45 mg MK-4 did not change bone density (Binkley 2009). A 2019 review of 36 vitamin K trials, all forms, found no effect on bone density or spine fractures after menopause; it may lower clinical fractures, but the evidence is too weak to confirm (Mott 2019).

We found no trial that compared MK-7 and MK-4 head to head on fractures or bone density. For MK-7’s own trials, see the doses the trials used.

MK-4 in blends

Most MK-4 pills and blends we read hold 5,000 mcg or less. One liquid gives 15,000 mcg a serving, a third of the drug dose. Figure 1 puts them side by side.

Figure 1. MK-4 per serving, next to the drug dose
0 12150 24300 36450 48600 MK-4 drug dose in Japan a day, as prescribed for osteoporosis (NIH) 45,000 mcg Thorne K2 Liquid: 15,000 mcg MK-4 only, 15 drops; on NSF/ANSI 173 15,000 mcg Thorne: 5,000 mcg plus 90 mcg MK-7 and 1,000 mcg K1 5,000 mcg Life Extension: 1,000 mcg plus 180 mcg MK-7 and 2,000 mcg K1 1,000 mcg NatureWise: 500 mcg plus 100 mcg MK-7 500 mcg InnovixLabs: 500 mcg plus 100 mcg MK-7 500 mcg NOW Foods: 100 mcg MK-4 only 100 mcg
The teal bar is the 45 mg (45,000 mcg) a day used as a drug in Japan. Every MK-4 product we read gives less in a serving; most give a small fraction. Source: NIH vitamin K fact sheet; each brand’s label, read October 5, 2026.
Figure 1. MK-4 per serving, next to the drug dose
ItemValue
MK-4 drug dose in Japan45,000 mcg
Thorne K2 Liquid: 15,000 mcg15,000 mcg
Thorne: 5,000 mcg5,000 mcg
Life Extension: 1,000 mcg1,000 mcg
NatureWise: 500 mcg500 mcg
InnovixLabs: 500 mcg500 mcg
NOW Foods: 100 mcg100 mcg

Blends sell MK-4 as “full spectrum.” No trial we found shows a blend works better than MK-7 alone. Blends with K1 add even more vitamin K, which matters if you take warfarin.

All-trans MK-7

MK-7 can come as all-trans or cis forms. In one 2022 lab study, the cis form had only slight activity next to all-trans; this has not been tested in people (Cirilli 2022). A 2018 test of MK-7 supplements found cis forms in many, likely from chemical manufacture, and all-trans MK-7 often below the label amount (Szterk 2018). Some brands name a branded MK-7 sold as all-trans; we read labels, but we did not test that claim.

Questions

Which foods have MK-7 and MK-4?

Natto, a Japanese fermented soybean food, is by far the richest: about 850 mcg of MK-7 in 3 ounces. MK-4 is in animal foods in small amounts, for example about 13 mcg in 3 ounces of chicken breast (NIH). Other K2 foods hold modest amounts.

Sources

  1. Sato T, Schurgers LJ, Uenishi K. Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women. Nutr J. 2012. PubMed 23140417
  2. Schurgers LJ, et al. Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood. 2007. PubMed 17158229
  3. Cockayne S, et al. Vitamin K and the prevention of fractures: systematic review and meta-analysis of randomized controlled trials. Arch Intern Med. 2006. PubMed 16801507
  4. Torgerson DJ. Caution to readers about systematic review on vitamin K and prevention of fractures that included problematic trials. JAMA Intern Med. 2018. PubMed 29582044
  5. Inoue T, et al. Randomized controlled study on the prevention of osteoporotic fractures (OF study): a phase IV clinical study of 15-mg menatetrenone capsules. J Bone Miner Metab. 2009. PubMed 19082528
  6. Binkley N, et al. Vitamin K treatment reduces undercarboxylated osteocalcin but does not alter bone turnover, density, or geometry in healthy postmenopausal North American women. J Bone Miner Res. 2009. PubMed 19113922
  7. Mott A, et al. Effect of vitamin K on bone mineral density and fractures in adults: an updated systematic review and meta-analysis. Osteoporos Int. 2019. PubMed 31076817
  8. Cheung AM, et al. Vitamin K supplementation in postmenopausal women with osteopenia (ECKO trial). PLoS Med. 2008. PubMed 18922041
  9. Schurgers LJ, Vermeer C. Differential lipoprotein transport pathways of K-vitamins in healthy subjects. Biochim Biophys Acta. 2002. PubMed 11960685
  10. Cirilli I, et al. Carboxylative efficacy of trans and cis MK7 and comparison with other vitamin K isomers. Biofactors. 2022. PubMed 35583412
  11. Szterk A, et al. Analysis of menaquinone-7 content and impurities in oil and non-oil dietary supplements. Molecules. 2018. PubMed 29724016
  12. NIH Office of Dietary Supplements. Vitamin K fact sheet for health professionals (updated March 29, 2021; read October 5, 2026).
  13. Labels: each brand’s page or the NIH Dietary Supplement Label Database, read October 5, 2026.