VCVITAMINS/CHART

The Bottom Line

Yes, you can take Vitamin K (K1, K2) and Green Tea Extract (EGCG) together — there is no significant interaction between these two supplements.

VERDICT

Vitamin K and Green Tea Extract together have no clinically meaningful interaction. Green tea extract does not block vitamin K absorption or interfere with its role in blood clotting. For most healthy adults, combining them is safe and requires no special timing.

Safe to combine Moderate evidence
01 / MECHANISM

How They Interact

Vitamin K is a fat-soluble vitamin absorbed in the small intestine alongside dietary fat and packaged into chylomicrons. EGCG, the main catechin in green tea extract, is water-soluble and absorbed through a different pathway involving intestinal transport proteins. There is no shared transporter, receptor, or enzyme that would cause competition between the two molecules. EGCG can inhibit certain CYP450 enzymes, but these are not involved in vitamin K metabolism. At typical supplement doses, neither compound alters the other's absorption, distribution, or function in a way that matters clinically. The only indirect connection is that both affect blood clotting through separate mechanisms — vitamin K enables clotting factors while EGCG has mild antiplatelet effects — but they do not negate or amplify each other's actions in a dangerous way.

02 / BEST PRACTICES

How To Take Them

To take vitamin K and green tea extract together, simply take them with a balanced breakfast that includes a source of fat. There is no need to space them apart or take them at different times of day. If you prefer, take vitamin K with your largest meal and green tea extract with a separate meal or snack, but this is not necessary for safety. If you miss a dose, do not double up on either supplement; just resume your normal schedule the next day. For optimal vitamin K absorption, pair it with foods like whole milk yogurt, cheese, or olive oil, while green tea extract can be taken with water or any beverage.

03 / FORM MATTERS

Form & Quality Differences

Vitamin K comes as K1 (phylloquinone, from plants) and K2 (menaquinone, especially MK-7 from bacteria). MK-7 has a longer half-life and may be absorbed slightly better than K1, but both forms interact identically with green tea extract. Green tea extract standardized to 50–90% EGCG is more concentrated than brewed tea, but the lack of interaction applies across all forms. There is no meaningful difference in how the interaction behaves between synthetic and natural versions of either supplement.

04 / COMMON STACKS

Where This Pair Shows Up

This pair is not a standard combination in commercial products, but vitamin K is frequently stacked with vitamin D and calcium for bone health, and green tea extract appears in thermogenic or antioxidant blends. When they do appear together, it is usually in a broad-spectrum multivitamin or morning wellness capsule.

Multivitamins Prenatals Performance Longevity
05

Practical Tips

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Frequently Asked Questions

Who Should Be Careful People taking anticoagulant medications such as warfarin should be cautious because vitamin K directly affects clotting factor production, and high-dose green tea extract may have mild antiplatelet effects, making the combined effect unpredictable. Pregnant and breastfeeding women should avoid concentrated green tea extract supplements unless a doctor approves, due to caffeine and catechin concerns. Anyone with liver disease or a history of liver problems should also use caution with green tea extract, as very high doses have been associated with rare hepatotoxicity. Older adults and those with digestive conditions that affect fat absorption should ensure adequate dietary fat when taking vitamin K.
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Sources & Further Reading

  1. NIH ODS NIH Office of Dietary Supplements — Vitamin K Fact Sheet
  2. NIH ODS NIH Office of Dietary Supplements — Green Tea Fact Sheet
  3. Examine.com Examine.com — Vitamin K interaction page
  4. Examine.com Examine.com — Green Tea Extract interaction page

Reviewed by Caroline M. on January 7, 2026 for accuracy against the sources listed above. This page is educational and is not a substitute for professional medical advice.

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The matrix has 86 supplements and 7310 pairwise interactions. Click any cell to see the full breakdown.

Back To The Vitamins Chart All Vitamin K (K1, K2) Interactions All Green Tea Extract (EGCG) Interactions