Vitamin K2 Dosage: How Much MK-7 to Take (and with Vitamin D)
Informational summary of published research — not medical advice. ⚠️ If you take warfarin, do NOT start, stop, or change vitamin K2 without your doctor managing it.
Quick answer
For the usual MK-7 form, take 90–200 mcg/day (the landmark trials used 180 mcg), once daily with a fatty meal. It's commonly paired with vitamin D (~100 mcg K2 alongside your D3). Note the MK-4 form is dosed in milligrams — ~250× higher. ⚠️ The critical rule: K2 opposes warfarin — never combine without a doctor.
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MK-7 vs MK-4: the doses are wildly different
The single biggest dosing mistake is treating the two forms as interchangeable. MK-7 works at micrograms (90–200 mcg) because it's well absorbed and has a long half-life, so it builds up in the blood (Schurgers 2007). MK-4 is cleared fast and barely detectable in blood at supplement amounts, so its research doses are in milligrams — up to 45 mg/day (the prescription osteoporosis dose in Japan), roughly 250× an MK-7 dose (Shiraki 2000; Sato 2012). Most everyday supplements use MK-7. For the full comparison, see MK-7 vs MK-4.
Find your vitamin K2 dose
Pick your reason for the MK-7 dose used in the trials and an honest read on the evidence.
Pairing K2 with vitamin D
K2 is often stacked with vitamin D3, and the logic is sound: vitamin D raises calcium absorption, while vitamin K2 activates the proteins (matrix Gla protein, osteocalcin) that steer that calcium into bone and away from arteries. A typical pairing is 100–200 mcg MK-7 with your D3, and combined softgels make it easy. Honest caveat: the mechanism and biomarker data support the combo, but hard outcomes are mixed — a 3-year trial of MK-7 added to D3 + calcium improved carboxylation markers but didn't change bone density (Rønn 2021). It's a reasonable, low-risk stack — not a guaranteed outcome.
By goal (what the trials used)
- Bone density: MK-7 180 mcg/day for 3 years slowed bone loss at the spine and femoral neck (but not total hip) in postmenopausal women (Knapen 2013); the MK-4 osteoporosis data uses 45 mg (Shiraki 2000).
- Arterial stiffness: MK-7 180 mcg/day for 3 years improved arterial stiffness (most clearly in women with stiffer arteries at baseline) and halved a vitamin-K-status marker (dp-ucMGP) (Knapen 2015). Higher dietary K2 intake tracked lower heart-disease risk in the observational Rotterdam Study (Geleijnse 2004).
- Honest limit: these are biomarkers and associations — no large trial has shown MK-7 supplements reduce actual heart attacks or strokes. One older open-label MK-4 trial (45 mg/day; Shiraki 2000) did report fewer fractures, but it wasn't blinded and used a ~250× higher dose — so it doesn't establish that MK-7 (the form most people take) prevents fractures. Promising, not proven.
MK-7 picks
100 mcg MK-7, 240 servings — the standard form at the lowest cost per day.
Vitamin D3 + 100 mcg MK-7 in one softgel — the convenient way to pair them.
300 mcg MK-7 if you want the upper end of the range; take with a fatty meal.
Compare all picks on the best vitamin K2 ranking, or see MK-7 vs MK-4.
Frequently asked questions
How much vitamin K2 should I take per day?
For MK-7 (the usual form), 90–200 mcg/day once daily with a fatty meal — the landmark trials used 180 mcg. MK-4 is different: research doses are 1,500 mcg up to 45 mg, ~250× higher. Not with warfarin unless your doctor manages it.
How much K2 with vitamin D?
Usually 100–200 mcg MK-7 alongside your D3 (combined softgels are common). Sound mechanism, but hard-outcome evidence is mixed — one trial improved markers without changing bone density. A reasonable low-risk stack, not a guarantee.
MK-7 vs MK-4 dose difference?
Large — MK-7 works at 90–200 mcg (long half-life, accumulates); MK-4 is cleared fast, so its studied doses are in milligrams (up to 45 mg), ~250× higher. 180 mcg MK-7 ≠ 180 mcg MK-4. Most supplements are MK-7.
Can I take K2 with warfarin?
Not on your own — the key safety rule. K2 opposes warfarin and can make it fail; even one typical MK-7 capsule can matter, and starting/stopping swings INR. Only with your prescribing doctor managing it. (Doesn't apply to apixaban/rivaroxaban — confirm with your doctor.)
Does K2 prevent heart disease?
Promising, not proven. MK-7 improved arterial stiffness and a K-status marker in a trial, and dietary K2 tracked lower heart disease in observational data — but those are surrogates/associations. No large trial shows K2 supplements cut actual heart attacks or strokes.
Related
- Vitamin K2: what the evidence shows
- MK-7 vs MK-4 — the forms compared
- Best Vitamin K2 Supplement
- Vitamin D Dosage Guide — the common partner
Sources
- Knapen MHJ, et al. "Three-year low-dose menaquinone-7 supplementation and bone loss." Osteoporos Int. 2013. PMID: 23525894
- Knapen MHJ, et al. "Menaquinone-7 improves arterial stiffness." Thromb Haemost. 2015. PMID: 25694037
- Geleijnse JM, et al. "Dietary menaquinone and coronary heart disease (Rotterdam Study)." J Nutr. 2004. PMID: 15514282
- Shiraki M, et al. "Vitamin K2 (menatetrenone) prevents fractures in osteoporosis." J Bone Miner Res. 2000. PMID: 10750566
- Schurgers LJ, et al. "Vitamin K1 vs natto-derived menaquinone-7; anticoagulant interference." Blood. 2007. PMID: 17158229
- Sato T, et al. "MK-4 vs MK-7 bioavailability in healthy women." Nutr J. 2012. PMID: 23140417
- Rønn SH, et al. "MK-7 on bone mineral density and microarchitecture (3-yr RCT)." Osteoporos Int. 2021. PMID: 33030563
- Couris R, et al. "Dietary vitamin K variability affects INR." Int J Vitam Nutr Res. 2006. PMID: 16941417