MK-7 vs MK-4: What's the Difference?

August 15, 2026

MK-7 vs MK-4: What’s the Difference?

Vitamin K2 exists in several natural forms called menaquinones, each identified by the length of their side chain. The two most common in supplements are MK-4 (menaquinone-4) and MK-7 (menaquinone-7). While both activate the same K2-dependent proteins in the body, they differ significantly in origin, half-life, and the evidence supporting their use.

Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any supplement, especially if you are pregnant, breastfeeding, taking medication, or have an underlying health condition. Do not exceed the recommended dose without medical supervision.

MK-4 (Menaquinone-4)

Source: MK-4 is not found in significant amounts in most foods. In supplements, it is typically produced synthetically via chemical conversion of phylloquinone (Vitamin K1).[1]

Half-life: Approximately 1–2 hours. MK-4 is rapidly absorbed but cleared from the bloodstream quickly, meaning blood levels drop significantly within hours of a dose.[2]

Dosing: Because of its short half-life, MK-4 requires multiple daily doses to maintain stable blood levels. Clinical studies using MK-4 typically use doses of 45mg (45,000µg) per day — far higher than the microgram doses used with MK-7.[3]

Evidence: MK-4 has been studied primarily in Japan at pharmacological doses (45mg/day) for osteoporosis treatment. At these doses, it has shown benefits for bone density. However, evidence for cardiovascular benefits at typical supplement doses is limited.[4]

MK-7 (Menaquinone-7)

Source: MK-7 occurs naturally in fermented foods, most abundantly in natto (fermented soybeans). In supplements, it is typically derived from natto or fermented chickpeas, making it suitable for vegans.[5]

Half-life: Approximately 72 hours. MK-7’s long side chain makes it highly lipophilic (fat-soluble), allowing it to remain in circulation for days. A single daily dose maintains stable, consistent blood levels.[6]

Dosing: Effective at microgram doses — typically 100–200µg per day. This is the dose range used in most human clinical trials showing bone and cardiovascular benefits.[7]

Evidence: MK-7 has the strongest evidence base for daily supplementation at physiological doses:

A 3-year randomised controlled trial by Knapen et al. found that 180µg MK-7 daily significantly reduced bone loss and improved bone strength in postmenopausal women[8]
Studies show MK-7 activates osteocalcin (directing calcium into bone) and Matrix Gla Protein (MGP, preventing arterial calcification) more effectively than MK-4 at comparable doses[9]
MK-7 has been shown to improve arterial stiffness markers in postmenopausal women[10]

MK-7 vs MK-4: Side-by-Side Comparison

	MK-4	MK-7
Source	Synthetic (from K1)	Fermented foods (natto)
Half-life	1–2 hours	~72 hours
Effective dose	45mg (45,000µg)	100–200µg
Dosing frequency	Multiple times daily	Once daily
Bone health evidence	Yes (at high doses)	Yes (at low doses)
Cardiovascular evidence	Limited at low doses	Stronger
Vegan-friendly	Yes	Yes
Common in supplements	Less common	Most common

Which Should You Choose?

For daily supplementation, MK-7 is the preferred form. Its long half-life means a single daily dose of 100–200µg maintains stable blood levels, and it has the strongest evidence for both bone and cardiovascular benefits at practical supplement doses.

MK-4 at pharmacological doses (45mg) has a role in clinical osteoporosis treatment, but this is a medical intervention rather than a standard supplement protocol.

Our Vitamin D3 3000 IU & K2 MK-7 100µg uses 100µg of MK-7 — the evidence-backed form at an effective daily dose, combined with D3 for synergistic bone and immune support.

For more on how D3 and K2 work together, see our guide: Vitamin D3 vs D3 + K2: Which Should You Take?

FAQs

Can I take MK-7 and MK-4 together?

Yes, though there is no strong evidence that combining them offers additional benefit over MK-7 alone at effective doses. Most quality supplements use MK-7 exclusively.

Does Vitamin K2 interfere with blood thinning medication?

Vitamin K (all forms) can affect the action of anticoagulants such as warfarin. If you are on blood thinning medication, consult your GP before taking any Vitamin K supplement.

Is MK-7 from natto the same as synthetic MK-7?

Natto-derived MK-7 (all-trans MK-7) is the biologically active form. Some synthetic MK-7 may contain a mixture of cis and trans isomers — only the all-trans form is active. Look for supplements that specify all-trans MK-7.

How long does K2 MK-7 take to work?

Osteocalcin carboxylation (activation) improves within weeks of consistent supplementation. Measurable effects on bone density markers typically require months of daily use.