Research
Vitamin K2 for Menopause: Evidence, Interactions and Cautions
Vitamin K2 is an ingredient used in menopause supplements marketed to women. Below is what it has actually been studied for, how strong that evidence is, the drug interactions and cautions on record, and the primary source our grade rests on — all drawn from the HerWellReport ingredient dataset.
Also sold as: Menaquinone; MK-4; MK-7; menatetrenone
What the evidence says about Vitamin K2
The strongest single trial gave 180 micrograms a day of MK-7 to 244 healthy postmenopausal women for three years and found it slowed the age-related decline in bone mineral content and density at the lumbar spine and femoral neck, with no change at the total hip. The NIH Office of Dietary Supplements notes an older systematic review found MK-4 reduced hip, vertebral and non-vertebral fractures, but later work found vitamin K did not alter bone turnover, density or geometry in healthy North American postmenopausal women, and co-supplementation with calcium and vitamin D confounds many trials. Vitamin K does not appear in the Menopause Society's 2023 nonhormone therapy position statement.
The grade "limited" means: limited — One or two small human trials, or trials for a closely related outcome. Grades are explained in full on our methodology page.
Read the primary source this grade rests on (opens in a new tab).
Vitamin K2 drug interactions
- Warfarin and other vitamin K antagonist anticoagulants
Who should be careful with Vitamin K2
- If you take warfarin, keep vitamin K intake steady and speak to your anticoagulation clinic before starting or stopping a K2 supplement, because sudden changes alter the anticoagulant effect
- no upper intake level has been set as toxicity is low
Read more on HerWellReport
- Best Menopause Supplements: What Is Actually In Them
- Confitrol24 Review (2026): The Trial Is Real, But the Label Doesn’t Say How Much
- O Positiv MENO Review: The Capsule and the Gummy Aren’t the Same Dose
- Urox Bladder Control Review (2026): The Trial Behind It, and the Hidden Dose
- Utiva Cranberry PACs Review (2026): Does the Dose Match?
This entry is generated from row "Vitamin K2 (menaquinone)" of the HerWellReport ingredient dataset (v2.1, updated 2026-09-23). The dataset is free to reuse under CC BY 4.0 — how to cite it. Ingredient evidence is not evidence for any finished product, and nothing here is medical advice.