Home Ingredients Vitamin K2 — MK-7 (Menaquinone-7)
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Vitamin K2 — MK-7 (Menaquinone-7)

Evidence Level
Moderate
3 Clinical Trials
5 Documented Benefits
3/5 Evidence Score

Vitamin K2 as menaquinone-7 (MK-7) is the long-chain menaquinone form most distinguished from short-chain MK-4 by its very long plasma half-life (~3 days vs ~1 hour), allowing stable serum levels and once-daily dosing. MK-7 is sourced commercially from controlled natto fermentation (Bacillus subtilis) and from chemical synthesis, with all-trans isomer purity as a critical quality attribute. Long-running randomized controlled trials in healthy postmenopausal women have shown that MK-7 at 180 mcg/day reduces age-related decline in bone mineral density at the lumbar spine and femoral neck, improves carotid-femoral pulse wave velocity, and reduces inactive matrix Gla protein — consistent with MK-7's role in carboxylating bone- and vascular-protective Gla proteins.

Studied Dose 180 mcg/day in bone/arterial-stiffness RCTs; maintenance 45-180 mcg/day.
Active Compound Menaquinone-7 (MK-7), all-trans isomer; from Bacillus subtilis (natto) fermentation or synthesis.

Benefits

Long-term bone density support

In a long-term randomized controlled trial in healthy postmenopausal women, MK-7 (180 mcg/day) reduced age-related decline in bone mineral content and bone mineral density at the lumbar spine and femoral neck vs placebo. Effects are modest compared with pharmaceutical osteoporosis therapy but were statistically significant over the multi-year window.

Supported by Trial 1

Arterial stiffness and vascular elasticity

Long-term MK-7 supplementation was associated with improvements in carotid-femoral pulse wave velocity and stiffness index in healthy postmenopausal women, alongside significant reductions in inactive matrix Gla protein — supporting MK-7's vascular health rationale.

Supported by Trial 2

Activation of vitamin-K-dependent Gla proteins

MK-7 supplementation reliably reduces circulating inactive osteocalcin and matrix Gla protein, indicating improved carboxylation status of these bone- and vascular-protective proteins — a mechanistic biomarker that underpins MK-7's clinical positioning.

Supported by Trial 2, Trial 1

Long half-life enables once-daily dosing

MK-7 has a plasma half-life of roughly 3 days, compared with about 1 hour for MK-4. Once-daily MK-7 dosing can therefore maintain stable, biologically meaningful circulating levels — practical for both consumer and clinical formulations.

Supported by Trial 3

Synergy with vitamin D3 supplementation

MK-7 is frequently co-formulated with vitamin D3 in bone and cardiovascular support products, based on the complementary mechanistic roles of D3 in calcium absorption and MK-7 in directing calcium into bone and away from vascular tissue via carboxylated osteocalcin and MGP.

Supported by Trial 1, Trial 2

Mechanism of action

1

Gamma-carboxylation of Gla-domain proteins

MK-7 is an essential cofactor for gamma-glutamyl carboxylase, which converts glutamate residues in Gla-domain proteins (osteocalcin, matrix Gla protein, GAS6, Protein S) to gamma-carboxyglutamate, enabling these proteins to bind calcium and perform their physiological functions.

2

Osteocalcin activation and bone matrix formation

Carboxylated osteocalcin binds hydroxyapatite and helps incorporate calcium into the bone matrix. Inadequate K2 leaves osteocalcin undercarboxylated and impairs this binding, contributing to age-related bone loss that MK-7 may help mitigate.

3

Matrix Gla protein activation and vascular protection

Carboxylated matrix Gla protein is the body's primary inhibitor of vascular calcification, limiting calcium phosphate deposition in vessel walls. K2 deficiency leaves MGP inactive and is associated with greater arterial calcification, which MK-7 supplementation may help reduce.

4

Long-chain menaquinone tissue distribution

MK-7's longer isoprenoid side chain supports efficient incorporation into circulating lipoproteins and extra-hepatic tissue delivery — explaining its disproportionate effect on extra-hepatic Gla proteins like osteocalcin and MGP relative to MK-4 or phylloquinone.

Clinical trials

1
MK-7 (180 mcg/day) for Bone Mineral Density in Postmenopausal Women — 3-Year RCT

Randomized, double-blind, placebo-controlled trial of MK-7 (180 mcg/day) vs placebo in 244 healthy postmenopausal women over 3 years. Outcomes: bone mineral density at lumbar spine and femoral neck, osteocalcin carboxylation status. Published in Osteoporosis International.

244 healthy postmenopausal women; 3-year intervention.

MK-7 significantly improved osteocalcin carboxylation and reduced age-related decline in bone mineral content and bone mineral density at the lumbar spine and femoral neck vs placebo. Effects were modest in magnitude compared with pharmaceutical osteoporosis therapy but reached statistical significance over the 3-year window.

2
MK-7 (180 mcg/day) and Arterial Stiffness — 3-Year RCT

Randomized, double-blind, placebo-controlled trial of MK-7 (180 mcg/day) vs placebo in 244 healthy postmenopausal women over 3 years. Outcomes: carotid–femoral pulse wave velocity, stiffness index, circulating inactive matrix Gla protein. Published in Thrombosis and Haemostasis.

244 healthy postmenopausal women; 3-year intervention.

Three-year MK-7 supplementation was associated with improvements in carotid–femoral pulse wave velocity and stiffness index vs placebo, alongside significant reductions in inactive matrix Gla protein, supporting MK-7's cardiovascular role.

3
MK-7 pharmacokinetics vs phylloquinone — Blood

Pharmacokinetic study comparing synthetic vitamin K1 (phylloquinone) and natto-derived MK-7 supplementation in healthy adults. Outcomes: plasma kinetics, half-life, accumulation. Published in Blood.

Healthy adult volunteers; pharmacokinetic study.

MK-7 demonstrated a very long plasma half-life and far more stable serum levels than phylloquinone, with 7- to 8-fold accumulation during prolonged intake. This pharmacokinetic profile supports once-daily dosing and explains MK-7's disproportionate effect on extra-hepatic vitamin K–dependent proteins.

Side effects and drug interactions

Common Potential side effects

Excellent safety profile at typical doses (45–180 mcg/day) of MK-7.
No clinically significant adverse events reported in multi-year MK-7 RCTs.
Mild GI discomfort possible with very high doses or in sensitive individuals.
Not extensively studied in pregnancy beyond dietary intake levels; consult clinician.
No tolerable upper intake limit established by most regulatory authorities for MK-7.

Important Drug interactions

Warfarin and other vitamin K antagonists — MK-7 directly opposes the drug's mechanism; coordinate carefully with anticoagulation clinic.
Direct oral anticoagulants (DOACs) — limited interaction data, but maintain consistent vitamin K intake.
Broad-spectrum antibiotics — may reduce intestinal K2 production; supplemental K2 may become more important.
Bile acid sequestrants and orlistat — may reduce absorption of fat-soluble vitamins including K2.

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Frequently asked questions about Vitamin K2 — MK-7 (Menaquinone-7)

What is vitamin K2 MK-7?

MK-7 (menaquinone-7) is a long-acting form of vitamin K2, typically sourced from natto (fermented soy) or produced by fermentation. It stays active in the body longer than MK-4, so once-daily dosing maintains steady levels.

What is vitamin K2 MK-7 used for?

MK-7 helps direct calcium into bone and away from arteries by activating proteins like osteocalcin and matrix Gla-protein. It is popular for bone and cardiovascular support and is often paired with vitamin D and calcium.

How much vitamin K2 MK-7 should I take?

Common doses are 90 to 180 mcg of MK-7 per day, taken with a meal containing fat for absorption. Its long half-life means once daily is enough to keep levels steady.

Who should be cautious with vitamin K2 MK-7?

Anyone taking the blood thinner warfarin should not start or change vitamin K supplements without medical guidance, since vitamin K opposes that drug. For most others, MK-7 is well tolerated and safe.

What is Vitamin K2 — MK-7?

Vitamin K2 as menaquinone-7 (MK-7) is the long-chain menaquinone form most distinguished from short-chain MK-4 by its very long plasma half-life (~3 days vs ~1 hour), allowing stable serum levels and once-daily dosing.

What is Vitamin K2 — MK-7 used for?

Vitamin K2 — MK-7 is researched primarily for Bone Health, Cardiovascular, and Longevity. In a long-term randomized controlled trial in healthy postmenopausal women, MK-7 (180 mcg/day) reduced age-related decline in bone mineral content and bone mineral density at the lumbar spine and femoral neck vs placebo.

What is the recommended dosage of Vitamin K2 — MK-7?

The clinically studied dose is 180 mcg/day in bone/arterial-stiffness RCTs; maintenance 45-180 mcg/day. Always follow the product label and check with a healthcare provider for personal advice.

Is Vitamin K2 — MK-7 safe, and does it have side effects?

For most healthy adults, Vitamin K2 — MK-7 is well tolerated at studied doses. Reported effects can include: Excellent safety profile at typical doses (45–180 mcg/day) of MK-7. No clinically significant adverse events reported in multi-year MK-7 RCTs. It may also interact with some medications. Vitamin K2 — MK-7 is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Vitamin K2 — MK-7 interact with any medications?

Possible interactions include: Warfarin and other vitamin K antagonists — MK-7 directly opposes the drug's mechanism; coordinate carefully with anticoagulation clinic. Direct oral anticoagulants (DOACs) — limited interaction data, but maintain consistent vitamin K intake. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Vitamin K2 — MK-7?

NutraSmarts rates the evidence for Vitamin K2 — MK-7 as Moderate (3 out of 5). It is backed by 3 clinical trials and 3 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(3 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Knapen MH, Drummen NE, Smit E, Vermeer C, Theuwissen E. Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporos Int. 2013;24(9):2499-507. doi: 10.1007/s00198-013-2325-6.PubMedUsed to support: 3-year RCT in 244 healthy postmenopausal women — MK-7 (180 mcg/day) significantly improved vitamin K status and decreased age-related decline in bone mineral content and bone mineral density at the lumbar spine and femoral neck vs placebo.
  2. Knapen MH, Braam LA, Drummen NE, Bekers O, Hoeks AP, Vermeer C. Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women. A double-blind randomised clinical trial. Thromb Haemost. 2015;113(5):1135-44. doi: 10.1160/TH14-08-0675.PubMedUsed to support: 3-year RCT in 244 healthy postmenopausal women — MK-7 (180 mcg/day) significantly improved carotid–femoral pulse wave velocity and stiffness index and reduced inactive matrix Gla protein vs placebo, supporting MK-7's cardiovascular role.
  3. Schurgers LJ, Teunissen KJ, Hamulyak K, Knapen MH, Vik H, Vermeer C. Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood. 2007;109(8):3279-83. doi: 10.1182/blood-2006-08-040709.PubMedUsed to support: Pharmacokinetic comparison showing MK-7 has a much longer plasma half-life than phylloquinone, with stable serum levels and 7–8-fold accumulation during prolonged intake — mechanistic basis for once-daily MK-7 dosing and extra-hepatic Gla-protein activation.