Which Tea Has Vitamin K? Exploring Green Tea, Matcha, and More

December 23, 2025 •

5 min read

According to nutritional data, most brewed teas contain negligible amounts of vitamin K, even though the leaves themselves possess it. So, which tea has vitamin K in a significant quantity? The key difference lies in whether you consume the whole tea leaf or just the brewed infusion.

Quick Summary

While many tea leaves contain vitamin K, the brewing process extracts very little into the final drink. Matcha is an exception because the whole leaf is consumed, resulting in higher vitamin K content.

Key Points

Matcha is a primary source of vitamin K among teas: Because it is made from powdered, whole tea leaves, matcha contains significantly more vitamin K than brewed teas.
Brewed teas contain negligible vitamin K: The brewing process does not effectively extract the fat-soluble vitamin K from the leaves into the water.
Blood thinner patients should exercise caution with matcha: Individuals on medications like warfarin must monitor their matcha intake due to its high vitamin K content.
Heavy consumption of any tea can be a concern: Drinking extremely large volumes of brewed green tea (e.g., a gallon a day) could introduce enough vitamin K to impact anticoagulant medication.
Herbal teas may interact with medications for other reasons: Some herbal ingredients, like those in chamomile or ginger tea, can affect blood clotting and require caution, even without significant vitamin K.
Dried tea leaves are higher in vitamin K than brewed tea: The vitamin K remains in the solid plant material, which is discarded in the brewing process.

The Surprising Truth About Brewed Tea and Vitamin K

Many people associate tea with a healthy lifestyle, but when it comes to specific nutrients like vitamin K, the details are more nuanced than commonly assumed. Vitamin K is a fat-soluble vitamin, which is a crucial detail when considering how much is extracted during the brewing process. While green and black tea leaves do contain vitamin K, the amount that ends up in a typical cup of brewed tea is remarkably low. This is because the vitamin does not easily dissolve in water, and the standard infusion method leaves the majority of the nutrients behind in the leaves.

Matcha: The Main Exception to the Rule

The most significant exception to the low-vitamin K rule is matcha green tea. Unlike traditional green tea, matcha is made from finely ground, powdered tea leaves. When you drink matcha, you are consuming the entire tea leaf, not just a water-based extract. This means that all the vitamins, including the fat-soluble vitamin K, are ingested directly. One to two teaspoons of matcha can contain the daily recommended intake of vitamin K, making it a potent source. This whole-leaf consumption method is what sets matcha apart nutritionally from other teas.

Other Teas: What to Expect

For black and oolong teas, the vitamin K content in the final brewed cup is also considered negligible. The fermentation process used to produce black tea does not alter the fact that the fat-soluble vitamins remain largely bound to the leaf material. Herbal teas can be more complex, as their vitamin K content depends entirely on the herbs used. For example, herbal teas containing ingredients like sweet clover or mint may have detectable levels, but a typical store-bought herbal infusion often contains very little.

The Importance of Consistency for Blood Thinner Patients

For individuals taking anticoagulant medications like warfarin (Coumadin), consistent vitamin K intake is vital. Large fluctuations can interfere with the medication's effectiveness. While a single cup of brewed green tea is unlikely to cause a problem, consuming large quantities (e.g., a half-gallon or more daily) could introduce enough vitamin K to diminish the medication's effect. This is why patients on blood thinners are often advised to regulate their intake of vitamin K-rich foods and beverages and to consult their doctor regarding any potential interactions.

How Brewing Affects Vitamin K

Here’s a step-by-step look at why the brewing process impacts vitamin K content:

Fat-Soluble vs. Water-Soluble: Vitamin K is a fat-soluble vitamin, meaning it dissolves in fats, not water. Most of the vitamins that are effectively extracted into a hot water infusion are water-soluble (like vitamin C or B-vitamins).
Limited Extraction: The brewing process involves steeping dried tea leaves in hot water. The duration and temperature are not sufficient to release significant amounts of fat-soluble vitamin K into the water.
Leaf Consumption vs. Infusion: The critical distinction is whether you consume the solid plant material. With matcha, the powdered leaf is consumed, ensuring all the vitamin K is ingested. With brewed teas, the leaves are discarded.
Potency Matters: While dried tea leaves are relatively high in vitamin K, a single serving of brewed tea is a very small portion of that. For example, 100g of dry green tea leaves contain much more vitamin K than a 100g serving of brewed tea.

Comparison of Vitamin K in Different Teas


Tea Type	Vitamin K Content (per serving)	Preparation Method	Notes for Warfarin Users
Matcha Green Tea	High (around 27-35 mcg per tsp)	Powdered leaves whisked into hot water	Monitor intake carefully; consult doctor due to high content.
Brewed Green Tea	Very low (approx. 0.6-0.8 mcg per cup)	Infusion of leaves in hot water	Moderate consumption generally safe; avoid large quantities.
Brewed Black Tea	Negligible (0.0 mcg in some analyses)	Infusion of leaves in hot water	Unlikely to cause issues due to very low content.
Brewed Oolong Tea	Negligible (0.0 mcg in some analyses)	Infusion of leaves in hot water	Unlikely to cause issues due to very low content.
Brewed Herbal Teas	Variable (often negligible)	Infusion of various herbs	Depends on the herb; some (e.g., chamomile, ginkgo) have other anticoagulant effects.

A Note on Herbal Teas and Blood Thinners

Some herbal teas, such as chamomile, ginkgo biloba, and ginger, have properties that can affect blood clotting independent of their vitamin K content. For this reason, individuals on blood thinners must be cautious with all herbal remedies and always consult their healthcare provider before adding new ones to their diet. Even without significant vitamin K, these herbs can interact with medications.

What are some high-vitamin K food sources?

Kale and other dark leafy greens
Spinach
Broccoli
Cabbage
Brussels sprouts
Soybeans and products like natto
Some fish and meat products

The Verdict: Which Tea Has Vitamin K?

The search for which tea has vitamin K leads to a clear conclusion: matcha green tea is the only common tea that serves as a significant source, primarily because the whole leaf is consumed. Other brewed teas, including green, black, and herbal varieties, contain minimal to no vitamin K due to the nature of the brewing process. While this makes most teas safe for moderate consumption by those monitoring their vitamin K intake, it also means they are not a reliable source of the nutrient. For individuals on blood thinners, understanding the difference between tea infusions and whole-leaf products like matcha is critical. Always consult a healthcare provider for personalized advice regarding diet and medication interactions. For more detailed information on interactions, you can reference resources like WebMD on Green Tea Interactions.

Conclusion

In summary, the vitamin K content in tea is highly dependent on its form. If you are drinking a standard brewed tea, the vitamin K content is negligible. However, if you are consuming a whole-leaf powder like matcha, you are ingesting a significant amount. This distinction is crucial for those who are monitoring their vitamin K intake for dietary or medical reasons. The method of preparation—infusion versus whole-leaf consumption—is the decisive factor in whether a tea contains a notable level of this essential vitamin.

Frequently Asked Questions

Brewed green tea has very little vitamin K because the vitamin is fat-soluble and does not dissolve well in water. However, dried green tea leaves contain substantial amounts, and matcha (powdered green tea) is a significant source because you consume the whole leaf.

For individuals on blood thinners like warfarin, moderate consumption of brewed green tea is generally not a concern. However, large quantities (e.g., 8 cups or more daily) should be avoided as they may contain enough vitamin K to interfere with medication. Matcha, due to its high vitamin K content, should be discussed with a doctor.

The main difference is the preparation method. Brewed green tea is an infusion where the leaves are discarded, leaving minimal vitamin K. Matcha involves consuming the entire powdered leaf, which contains all the vitamin K present in the plant.

Most brewed herbal teas contain negligible amounts of vitamin K. The content depends on the specific herb, but since it's an infusion, very little is extracted into the water. Some herbs, however, can have other effects on blood clotting.

Matcha green tea has the highest vitamin K concentration among commonly consumed teas because you ingest the whole powdered leaf, rather than just drinking an infusion.

Brewed black tea contains negligible amounts of vitamin K and is unlikely to interfere with medications like blood thinners based on its vitamin K content alone. Always consult your doctor, however, for personalized medical advice.

No, people on warfarin do not need to avoid all tea, but they should be consistent with their intake and avoid large, irregular quantities of vitamin K-rich sources. Brewed green, black, and most herbal teas are fine in moderation, but matcha and very large amounts of brewed green tea should be approached with caution and medical supervision.