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Best Vitamin K Supplement (2026): K1, MK-7, MK-4, D3+K2 Ranked

By Erin Rose · Updated · Methodology · About Us

Also searched: best vitamin K supplement, best K1 supplement, best MK-7 vs MK-4, vitamin K for warfarin patients.

Informational summary of published research — not medical advice. If you take warfarin or another vitamin K antagonist, talk to your prescribing clinician and get INR monitoring before starting any product on this page. As an Amazon Associate we earn from qualifying purchases; picks are ranked by form-fit and cost per day, never commissions. This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.

The right vitamin K product depends on your goal and, above all, whether you take a blood thinner. Vitamin K forms are not interchangeable by the microgram, so this ranking sorts by form-fit first — which form actually answers your question — and cost per day second.

Best K1: Bluebonnet Vitamin K1 100 mcg at $0.10/day — general food-gap insurance near the adult AI.

Best MK-7: NOW Foods MK-7 100 mcg at $0.22/day — the trial-anchored bone/artery-mechanism dose (see the full MK-7 shootout for deeper MK-7-only picks).

On warfarin or another VKA? None of these are yours to start on your own — see our warfarin and blood thinners guide first.

Our Picks at a Glance

Best vitamin K supplements ranked by form-fit, then cost per day
Award Product Form Dose Best for Cost/Day Buy
Best K1 (food-gap insurance) Bluebonnet Vitamin K1 100 mcg K1 (phylloquinone) 100 mcg Standalone phylloquinone near the 90-120 mcg adult AI — the form your liver actually uses for clotting. $0.10 Check price →
Best MK-7 NOW Foods MK-7 Vitamin K2 100 mcg K2 (MK-7, all-trans) 100 mcg Branded MenaQ7 all-trans MK-7 at the standard clinical dose — the form used in nearly every K2 bone/artery trial. $0.22 Check price →
Best Value MK-7 Nutricost Vitamin K2 MK-7 100 mcg K2 (MK-7) 100 mcg The same trial-anchored 100 mcg MK-7 dose at the lowest cost per day. $0.07 Check price →
Best D3 + K2 Combo Nutricost Vitamin D3 (5,000 IU) + K2 (MK-7 100 mcg) D3 5,000 IU + K2 (MK-7) 100 mcg K2 D3 and MK-7 in one softgel for convenience — see our D3-with-K2 guide before assuming a ratio is validated. $0.12 Check price →
MK-4 (know the caveat) NOW Foods Vitamin K-2 100 mcg, Menaquinone-4 (MK-4) K2 (MK-4) 100 mcg A nutritional dose only — NOT the 45 mg/day pharmacologic dose used in the Japanese osteoporosis-drug trials. $0.10 Check price →
Most Complete Thorne Vitamin K (K1 + MK-4 + MK-7) K1 + MK-4 + MK-7 blend blend, see label Broadest single-product coverage across all three forms — a premium, third-party-tested pick. $0.52 Check price →

Prices verified 2026-07-19. Cost per day is computed at the label serving; the Thorne blend assumes a 1-capsule serving — confirm on your bottle.

How to pick the right form for you

  1. You take warfarin or another VKA anticoagulant. Stop here and read our warfarin guide — nothing below is a self-serve decision for you.
  2. You just want food-gap insurance. A standalone K1 at 45-120 mcg is reasonable — it's near the adult AI and it's the form your liver already uses. Most people who eat any leafy greens are already close to adequate, so this is a low-stakes, low-cost add.
  3. You're interested in the bone/artery mechanism. MK-7 at the trial-anchored 90-200 mcg range is the form nearly every K2 clinical trial used — Knapen's two landmark 3-year trials both ran 180 mcg/day (in healthy postmenopausal women only, and both industry-funded by VitaK/MenaQ7 vitamin-K interests — not established in men or younger adults). Be honest with yourself about the evidence: it's mechanistically strong and outcome-mixed (see our hub page for the full breakdown). For a deeper MK-7-only shootout with more picks, see our dedicated MK-7 ranking and MK-7 vs MK-4.
  4. You specifically want MK-4. Understand what you're buying first: a 45-100 mcg retail MK-4 capsule is a nutritional dose. The Japanese osteoporosis-drug trials used 45 mg/day (45,000 mcg) — a pharmacologic dose about 450x higher (Miki 2003). A human PK study found nutritional-dose MK-4 doesn't even register in serum (Sato 2012). A retail MK-4 bottle does not replicate that drug-trial evidence — don't buy one expecting it to.
  5. You want vitamin D and K2 in one pill. A D3+K2 combo is a legitimate convenience choice, not a superior one — the "45 mcg K2 per 1,000 IU D3" ratio on the label is a formulation convention, not a validated dose. See vitamin D with K2 for the full pairing discussion.
  6. You want broad coverage in one product. A K1 + MK-4 + MK-7 blend covers all three forms without stacking bottles — reasonable if you want breadth, though a standalone MK-7 remains the most trial-anchored single choice.

What we don't recommend

  • Assuming any 100 mcg "K2" or "MK-4" bottle replicates the Japanese osteoporosis drug trials. It doesn't — that evidence used a 45 mg/day pharmacologic dose, a different tier entirely.
  • Products marketed as "reversing" or "cleaning out" arterial calcification. The trials that measured actual calcification came back negative; K2 supports the calcium-routing system, it doesn't dissolve existing plaque.
  • Starting, stopping, or switching any of these while on warfarin without your prescriber. This is the one rule that overrides every other recommendation on this page.

Frequently Asked Questions

What is the best vitamin K supplement?

It depends on your goal and, above all, whether you take a blood thinner — if you take warfarin or another vitamin K antagonist, talk to your prescribing clinician before starting anything on this page. For general food-gap insurance, a standalone K1 like Bluebonnet Vitamin K1 100 mcg is reasonable. For the bone/artery mechanism most people are actually chasing, an all-trans MK-7 at 100 mcg (NOW Foods or Nutricost) is the trial-anchored pick. Avoid assuming a 100 mcg MK-4 bottle replicates the 45 mg/day Japanese osteoporosis drug trials — it does not.

Should I buy K1, MK-7, or MK-4?

K1 for general dietary insurance near the 90-120 mcg Adequate Intake — most people who eat leafy greens don't need it. MK-7 for the bone/artery mechanism at the trial-anchored 90-200 mcg dose — this is the form nearly every K2 clinical trial used. MK-4 only if you understand the retail 45-100 mcg dose is nutritional, not the 45 mg/day pharmacologic dose the Japanese bone trials used — a roughly 450x gap. See our full MK-7 vs MK-4 comparison for the mechanics.

Is a D3+K2 combo better than taking them separately?

Neither is medically superior — a combo is purely a convenience choice. The "45 mcg K2 per 1,000 IU D3" ratio printed on combo labels is a formulation convention, not a validated dose from any dose-ranging trial. The mechanistic logic (D raises calcium absorption, K2 helps route it) is sound, but a standalone MK-7 at 90-200 mcg works just as well if you'd rather control each dose independently.

Can I take any of these if I'm on warfarin?

Not without your prescribing clinician and INR monitoring — full stop. Vitamin K, in any form on this page, directly opposes warfarin and other vitamin K antagonists. This is not a "check with your doctor as a formality" caveat; starting, stopping, or changing vitamin K intake without medical supervision can meaningfully destabilize anticoagulation. See our dedicated warfarin and blood thinners guide before considering any product here.

Related Guides

Sources

  1. Miki T, Nakatsuka K, Naka H, et al. "Vitamin K(2) (menaquinone 4) reduces serum undercarboxylated osteocalcin level as early as 2 weeks in elderly women with established osteoporosis." J Bone Miner Metab. 2003;21(3):161-5. PMID: 12720050
  2. Sato T, Schurgers LJ, Uenishi K. "Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women." Nutr J. 2012;11:93. PMID: 23140417
  3. Knapen MHJ, et al. "Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women." Osteoporos Int. 2013;24(9):2499-507. PMID: 23525894
  4. Daley SF, Sina RE. "Vitamin K Deficiency in Neonates and Adults." StatPearls (NCBI Bookshelf). 2026. PMID: 30725668