Vitamin K2: NOW MK-7 Vitamin K-2 100 mcg, 120 Veg Capsules

What the label shows

We read the Supplement Facts, suggested-use and caution panels from the bottle images on the Amazon listing for the 120-capsule size on Sep 30, 2026.

Suggested use is one capsule daily with a meal. The bottle's caution reads, in substance: adults only; consult a physician if pregnant or nursing, taking medication (especially anticoagulant drugs, naming warfarin), or managing a medical condition. The front label's bone and cardiovascular structure/function lines are the seller's wording; this entry rates only the bone-density question and does not rate the cardiovascular one.

What the research shows

Background. Vitamin K is a cofactor for enzymes that activate proteins involved in blood clotting and in bone metabolism, including osteocalcin, a bone protein [1]. Menaquinones (vitamin K2) come in several chain lengths; MK-4, MK-7 and MK-9 are the most studied, and natto is an unusually rich food source of MK-7. The ODS fact sheet sets Adequate Intakes for adults at 120 mcg a day for men and 90 mcg for women, for vitamin K from all forms, and notes that no upper limit was set because of its low potential for toxicity.

What the wider vitamin K research shows. ODS summarizes the evidence as unclear on whether supplementation with any form of vitamin K benefits bones [1]. Much of the early positive evidence came from Japanese trials using MK-4 at 45 mg a day, a pharmacological amount hundreds of times larger than this capsule, while later trials summarized by ODS found no effect on bone density. A 2019 systematic review and meta-analysis in Osteoporos Int pooled randomized trials of oral vitamin K in adults [5]. For postmenopausal women and people with a diagnosed bone-thinning condition, it found no evidence that vitamin K affects bone mineral density; differences tended to shrink and lose statistical significance when trials at high risk of bias were removed. It judged the evidence on other outcomes insufficient to confirm an effect, and found too few trials to draw conclusions about other groups.

Trials of MK-7. Three randomized, placebo-controlled trials of MK-7 in postmenopausal women illustrate the split. A Dutch trial of 244 healthy women given 180 mcg a day for three years reported a slower age-related decline in bone mineral density at the lumbar spine and femoral neck, though not at the total hip, and better calculated bone-strength indices [2]. A Norwegian double-blind trial of 334 women aged 50 to 60, one to five years past menopause, given 360 mcg a day as natto capsules for one year, found no difference in bone loss at any site [3]. A Danish double-blind trial of 142 women with below-average bone density, given 375 mcg a day on top of calcium and vitamin D for three years, found no differences in bone density, bone-turnover markers or bone microarchitecture [4]. In all three, MK-7 improved the blood marker of vitamin K status.

Where that leaves the reading. These are reasonably sized, long trials, which is to their credit, but the best of them disagree, the one positive MK-7 result has not been replicated, and the pooled evidence for vitamin K overall does not show a clear effect on bone density. We place that between a 2 and a 3 and, following our rule, take the lower reading. It concerns bone density only and says nothing about any other use named on the label.

Study dose vs. label dose

Where the hype comes from

K2's story is built on real biology: vitamin K is needed to activate osteocalcin, and supplements do shift that marker. The step that has not held up consistently is the jump from marker to measurable bone outcomes in people eating ordinary diets. K2 is also often sold next to vitamin D, and ODS notes that giving vitamin D or calcium alongside vitamin K may partly explain why some trials found benefits and others did not [1].

Price and where it is sold

On Sep 30, 2026 the Amazon listing for NOW MK-7 Vitamin K-2 100 mcg, 120 veg capsules, showed $20.20, in stock, sold by Amazon.com. The listing marked the item as non-returnable for food safety reasons. Check the listing for the price on the day you look.

Who should look elsewhere

• Anyone taking warfarin or another anticoagulant should talk to their prescriber before taking any vitamin K product.
• People who want the doses used in the MK-7 trials would need more than one capsule a day; ask a clinician before doing so.
• Anyone concerned about bone density should talk with a clinician about testing and well-established basics such as calcium, vitamin D and physical activity, rather than relying on K2.

Sources

1. NIH Office of Dietary Supplements. Vitamin K fact sheet for health professionals (forms, Adequate Intakes, bone research summary, warfarin interaction). Updated Mar 29, 2021. Accessed Sep 30, 2026. link
2. Osteoporos Int. Three-year randomized, placebo-controlled trial of 180 mcg/day MK-7 in 244 healthy postmenopausal women, measuring bone density and strength. 2013;24(9):2499–2507. PubMed
3. Osteoporos Int. One-year randomized, double-blind, placebo-controlled trial of 360 mcg/day MK-7 in 334 early postmenopausal Norwegian women. 2010;21(10):1731–1740. PubMed
4. Osteoporos Int. Three-year randomized, double-blind, placebo-controlled trial of 375 mcg/day MK-7 with calcium and vitamin D in 142 postmenopausal women with below-average bone density. 2021;32(1):185–191. PubMed
5. Osteoporos Int. Updated systematic review and meta-analysis of randomized controlled trials of oral vitamin K and bone outcomes in adults. 2019;30(8):1543–1559. PubMed

This entry is educational and is not medical advice. The signal reading describes published research on one use; it is not a recommendation to take anything. Ask a qualified clinician or pharmacist before starting any supplement, especially if you are pregnant, nursing, have an existing condition, or take medication.