Does vitamin K help with perimenopause symptoms?

Vitamin K is an often-overlooked nutrient during perimenopause, but its roles in bone metabolism, arterial health, and cardiovascular protection make it increasingly relevant as estrogen declines. Understanding the two main forms of vitamin K and how they differ clarifies where the evidence is strongest.

Vitamin K1 (phylloquinone) is found primarily in leafy green vegetables such as kale, spinach, and broccoli. It is best known for its role in activating clotting factors in the coagulation cascade. Without K1, proper blood clotting is impaired. For most people eating a diet with reasonable amounts of vegetables, K1 deficiency is uncommon.

Vitamin K2 (menaquinone) is the form with the most compelling evidence for perimenopausal health. K2 is produced by certain gut bacteria and is also found in fermented foods (particularly natto, a fermented soybean product with very high K2 content) and some animal products. K2 activates two critical proteins: osteocalcin, which anchors calcium into bone matrix, and matrix Gla protein (MGP), which prevents calcium from depositing in arteries and soft tissues. Both functions become especially relevant as estrogen declines during perimenopause.

Estrogen normally supports bone mineral density and limits bone turnover. As estrogen falls during perimenopause, bone resorption accelerates and fracture risk begins to rise years before menopause is reached. K2 supports bone health by activating osteocalcin, the protein responsible for incorporating calcium into bone in the right structural form. Without adequate K2, calcium that is absorbed from food or supplements may not be deposited efficiently in bone.

A study by Knapen and colleagues in 2007 followed postmenopausal women taking vitamin K2 (specifically MK-7, a long-acting menaquinone form) and found that it significantly slowed bone density loss and improved bone strength markers compared to placebo. This is the most directly relevant clinical evidence for vitamin K2 in the peri and postmenopausal context.

The arterial health mechanism through MGP activation is an important complementary benefit. As women age and lose estrogen's protective cardiovascular effects, arterial calcification risk increases. K2's role in activating MGP, which actively removes calcium from arterial walls, may help protect vascular health alongside bone health. Adequate K2 is associated with lower rates of coronary calcification in observational research.

MK-7 (menaquinone-7) is the most bioavailable and longest-acting form of K2 and is found in natto and used in most high-quality K2 supplements. MK-4 is another form found in animal products and used in some supplements, with a shorter half-life.

Studies have used a range of K2 doses. Talk to your healthcare provider about what is appropriate for your situation.

A critical safety note: vitamin K directly antagonizes the mechanism of warfarin (and other vitamin K antagonist anticoagulants). If you take warfarin, any change in your vitamin K intake, whether from food or supplements, can alter your INR and anticoagulation level in ways that may be dangerous. Anyone on warfarin must discuss vitamin K with their provider and have INR monitored if making dietary or supplemental changes.

For women not on warfarin, vitamin K is generally very safe at dietary and typical supplemental levels. There is no established upper intake level for toxicity, though this reflects limited data rather than confirmed safety at all doses.

PeriPlan allows you to track bone-related symptoms, joint comfort, and overall wellbeing as you monitor your nutritional supplement strategy over time. Bone density changes are assessed through imaging rather than symptoms, so DEXA scans at appropriate intervals provide objective data that complements symptom tracking.

When to see a doctor: Ask your provider about a baseline DEXA bone density scan during perimenopause to know where you stand. If your diet is low in green vegetables or fermented foods, ask whether K2 supplementation makes sense alongside any calcium and vitamin D you may already be taking. Anyone with a clotting disorder or on anticoagulant medications must discuss vitamin K with their provider before making changes.

This content is for informational purposes only and does not replace medical advice. Always consult your healthcare provider about your specific situation.