Vitamin K2 (Menaquinone-7)
Vitamin K2 is a fat-soluble vitamin that plays a crucial role in calcium metabolism, directing calcium to bones and teeth while preventing its accumulation in arteries and soft tissues. The MK-7 form has superior bioavailability and longer half-life compared to other forms of vitamin K. Dietary supplements are not FDA-approved to diagnose, treat, cure, or prevent any disease. Consult your doctor before starting any supplement.
Key Takeaways
- Vitamin K2 as MK-7 (menaquinone-7) has superior bioavailability and longer half-life compared to other forms, making it the preferred choice for supplementation
- Clinical studies show no toxicity at doses up to 45,000 mcg daily for up to two years, with typical beneficial doses ranging from 100-180 mcg daily
- Works by activating proteins that direct calcium to bones and teeth while preventing arterial calcification, supporting both bone health and cardiovascular function
- Most beneficial for adults over 50, postmenopausal women, and those with limited intake of fermented foods or organ meats
- Does not affect blood clotting in healthy individuals not taking anticoagulant medications, unlike vitamin K1
How to Take
Typical Dosage
100-200 mcg daily based on clinical research. Studies have safely used doses up to 45,000 mcg (45 mg) for up to two years, though such high doses are not typically necessary for general health benefits.
When to Take
With meals containing fat for optimal absorption, as vitamin K2 is fat-soluble. Daily administration is preferred due to the body's low storage capacity.
Why It Matters for Ages 50+
Adults over 50 experience increased bone loss and arterial calcification, making vitamin K2's dual role in bone health and cardiovascular protection particularly valuable. Age-related changes in gut bacteria production and dietary absorption may reduce natural vitamin K2 levels. Research specifically in postmenopausal women shows significant benefits for bone turnover markers and osteocalcin activation.
What to Look For
- Choose menaquinone-7 (MK-7) form over MK-4 for better absorption and longer duration of action
- Look for third-party testing certification to verify purity and potency, especially for contaminants
- Select products that specify 'all-trans' MK-7, which is the bioactive form rather than synthetic 'cis' forms
- Ensure proper packaging in dark bottles or blister packs to protect from light degradation
- Verify the product is manufactured in GMP-certified facilities and contains minimal additives or fillers
Potential Interactions
Be aware of these potential interactions:
- Anticoagulants (warfarin, Coumadin): May reduce effectiveness of blood thinners by promoting clotting. Requires careful INR monitoring and dose adjustments
- Antiplatelet drugs (aspirin, Plavix): May counteract antiplatelet effects. Maintain consistent intake and monitor with healthcare provider
- Novel anticoagulants (Eliquis, Xarelto): Potential interaction with clotting cascade. Consult prescribing physician before use
- Fat absorption inhibitors (orlistat/Alli): May reduce vitamin K2 absorption. Take supplements at different times
- Bile acid sequestrants (colesevelam, cholestyramine): Can impair fat-soluble vitamin absorption including K2
- Antibiotics (broad-spectrum): May reduce vitamin K production by gut bacteria, potentially altering K2 needs
Who Should Avoid This Supplement
- Individuals taking any anticoagulant medications (warfarin, newer blood thinners) without medical supervision
- People with active bleeding disorders or those scheduled for surgery within two weeks
- Individuals with severe liver disease, as vitamin K metabolism may be impaired
- Those with rare genetic conditions affecting vitamin K metabolism or clotting factor production
Recommended by Experts
“Takes 100 mcg MK-7 form daily as 'insurance' for calcium utilization”
“Takes with D3 for blood vessel health and bone support”
Frequently Asked Questions
Research suggests 100-180 mcg daily is beneficial for most adults. Studies have safely used doses up to 45,000 mcg, but typical supplement doses of 100-200 mcg are sufficient for bone and cardiovascular support.
Take vitamin K2 with a meal containing some fat, as it's a fat-soluble vitamin requiring dietary fat for optimal absorption. Taking it with your largest meal of the day maximizes uptake.
Vitamin K2 is primarily found in fermented foods like natto, aged cheeses, and organ meats, which many people don't consume regularly. Supplementation ensures consistent intake since dietary sources are limited in typical Western diets.
Biochemical markers improve within 2-4 weeks, but meaningful changes in bone density or arterial calcification typically require 6-12 months of consistent use. Some cardiovascular benefits may be observed within 3-6 months.
Yes, K1 primarily supports blood clotting while K2 activates proteins involved in calcium metabolism and arterial health. K2, especially MK-7, is more effective for bone and cardiovascular longevity benefits.
Vitamin K2 is generally well-tolerated with no reported toxicity in healthy individuals. Rare side effects may include mild digestive upset, and it should not affect blood clotting in those not on anticoagulant medications.