Can You Take Nattokinase and Vitamin K2 at the Same Time?

November 14, 2025 •

4 min read

In Japan, the traditional dish natto, made from fermented soybeans, has been consumed for centuries and is a natural source of both nattokinase and vitamin K2. This fact addresses the common question of whether you can take nattokinase and vitamin K2 at the same time, suggesting a natural and complementary relationship between the two compounds.

Quick Summary

The combined intake of nattokinase and vitamin K2 is generally considered safe and beneficial for cardiovascular health, as they work synergistically rather than antagonistically. Nattokinase promotes healthy blood flow by breaking down excess fibrin, while vitamin K2 directs calcium away from arteries and into bones. Professional guidance is essential, especially for individuals on anticoagulant medication.

Key Points

Synergistic Relationship: Nattokinase and vitamin K2 are not opposing forces; they work together to support cardiovascular health by addressing different aspects of blood and arterial health.
Balanced Clotting: Nattokinase dissolves excess fibrin to improve blood flow, while vitamin K2 activates the proteins needed for necessary, injury-related blood clotting.
Arterial Health: Vitamin K2 prevents calcium buildup in the arteries, maintaining their flexibility, a function that complements nattokinase's role in promoting healthy circulation.
Pre-existing Conditions: Individuals on anticoagulant medications (e.g., warfarin) or with bleeding disorders must consult a doctor before taking these supplements.
Optimal Timing: Taking nattokinase on an empty stomach and vitamin K2 with a meal containing fat may optimize absorption, though consistency is more important.
Natural Precedent: The traditional Japanese food natto naturally contains both nattokinase and vitamin K2, providing a real-world example of their effective and safe combination.

Understanding the Individual Roles of Nattokinase and Vitamin K2

Before delving into their combined effects, it is crucial to understand the distinct functions of nattokinase and vitamin K2. Both play vital roles in cardiovascular wellness but operate through different mechanisms.

What is Nattokinase?

Nattokinase is an enzyme derived from natto, a Japanese food of fermented soybeans. It is known for its potent fibrinolytic properties, meaning it helps break down fibrin, a protein that forms blood clots. By supporting the body's natural processes for breaking down clots, nattokinase promotes healthy blood flow and circulation. This is why it is often referred to as a natural "blood thinner" and is studied for its potential benefits in preventing and managing cardiovascular diseases.

What is Vitamin K2?

Vitamin K2, specifically the menaquinone form (MK-7, MK-4), is a fat-soluble vitamin crucial for calcium metabolism. Its primary role is to activate specific proteins that help regulate calcium in the body. This includes directing calcium to the bones and teeth for proper mineralization and, importantly, preventing its buildup in soft tissues like the arteries. Excessive arterial calcification can contribute to arterial stiffness and cardiovascular issues, making vitamin K2 a key player in maintaining flexible blood vessels.

The Synergistic Relationship: Complementary, Not Conflicting

Despite their seemingly opposite effects on blood clotting—nattokinase as a clot dissolver and vitamin K as a clotting factor—they work together harmoniously. The critical distinction lies in their mechanisms of action and the specific types of clotting they influence.

How They Work Together

Balanced Blood Health: Nattokinase helps dissolve pre-existing and unnecessary clots formed by excess fibrin, while vitamin K2 activates the proteins needed for appropriate blood clotting in response to an injury. This means that the body's ability to heal wounds and stop bleeding is not compromised, but the risk of unnecessary clotting is reduced.
Calcium Regulation and Arterial Health: The combination of nattokinase and vitamin K2 provides dual support for the cardiovascular system. Nattokinase ensures smooth blood flow by addressing clot formation, while vitamin K2 helps maintain clear, elastic arteries by controlling calcium accumulation. This synergistic effect is beneficial for overall heart and vascular health.

Evidence for Combined Use

Scientific research supports the complementary nature of these two compounds. A large-scale study on nattokinase found that co-administering vitamin K2 had a synergistic effect on lipid levels. This reinforces the idea that their combined action can offer comprehensive cardiovascular support beyond what each can provide individually. Furthermore, since the food source natto naturally contains both, it serves as a long-standing historical precedent for their safe and effective combination.

Safety Considerations and Medical Consultation

While combining nattokinase and vitamin K2 is generally safe for most people, certain precautions are essential, and professional medical advice is paramount.

Important Considerations

Dosage and Formulation: For supplements, checking the label is crucial, as isolated nattokinase products are often sold without vitamin K2. Many brands, however, offer combined formulations to deliver both benefits in a single softgel.
Timing of Intake: For best results, nattokinase is often recommended on an empty stomach, while fat-soluble vitamin K2 is better absorbed with a meal. Taking them at different times may optimize their respective absorption. Consistency, however, is key for long-term benefits.

Comparison: Taking Nattokinase and Vitamin K2


Feature	Nattokinase Alone	Vitamin K2 Alone	Combined Supplementation
Primary Function	Dissolves fibrin clots for improved blood flow	Directs calcium to bones, away from arteries	Supports both healthy blood flow and arterial elasticity
Cardiovascular Impact	Focuses on clot prevention and blood viscosity	Focuses on preventing arterial calcification	Comprehensive support for vascular and circulatory health
Synergy	None	Limited, needs other nutrients for maximum effect	Synergistic, with studies showing complementary benefits
Blood Clotting	Inhibits excessive clotting	Activates clotting proteins when needed	Maintains healthy, balanced blood clotting response
Timing	Best on an empty stomach	Best with a meal containing fat	Can be staggered or combined depending on product

Potential Risks and Contraindications

There are situations where the combined intake of nattokinase and vitamin K2 is not recommended without strict medical supervision.

Anticoagulant Medications: People taking blood-thinning medications like warfarin must avoid this combination, as vitamin K can counteract warfarin's effect, while nattokinase can increase bleeding risk. A physician's guidance is essential.
Pre-Surgery: Nattokinase might increase bleeding risk during or after surgery. Discontinue use at least two weeks prior to any scheduled operation.
Bleeding Disorders: Individuals with bleeding disorders should not take nattokinase due to the heightened risk of excessive bleeding.
Pregnancy and Breastfeeding: There is insufficient reliable information on the safety of nattokinase during pregnancy or while breastfeeding, so it is advised to avoid supplementation.

Conclusion

The combination of nattokinase and vitamin K2 is widely regarded as a safe and effective strategy for complementary cardiovascular support, not a conflicting one. As demonstrated by the Japanese diet staple natto, these compounds naturally exist together and provide distinct yet supportive actions: nattokinase helps dissolve unnecessary clots for better blood flow, while vitamin K2 manages calcium to promote arterial health. However, the critical caveat is that individuals on anticoagulant medication or with bleeding disorders must consult a healthcare professional before taking these supplements. For healthy individuals seeking a synergistic approach to heart and vascular health, a balanced supplement regimen combining these two powerful nutrients can be a beneficial part of a holistic wellness plan.

Frequently Asked Questions

No, they will not cancel each other out. Nattokinase and vitamin K2 have different but complementary functions. Nattokinase helps dissolve excess fibrin to prevent unnecessary clots, while vitamin K2 ensures normal blood clotting occurs only when needed for injuries.

Yes, many manufacturers offer combined supplements. For healthy individuals, this is generally considered safe and beneficial. The key is to ensure the product has been properly formulated to deliver both nutrients effectively.

Individuals on anticoagulant medications like warfarin, those with known bleeding disorders, and those scheduled for surgery should avoid taking nattokinase and vitamin K2 supplements without a doctor's guidance.

For optimal absorption, some sources suggest taking nattokinase on an empty stomach and vitamin K2 with a meal, as it is fat-soluble. However, many people take them together, and consistency is often the most important factor.

While these supplements support overall cardiovascular health by promoting healthy blood flow and preventing arterial calcification, they should not be considered a treatment or cure for heart conditions. Always follow your doctor's advice for managing heart health.

Yes, the Japanese fermented soybean dish natto is a natural source of both nattokinase and vitamin K2 (specifically MK-7). Other fermented foods and certain animal products also contain vitamin K2.

Nattokinase may influence blood clotting factors within hours, but for benefits like blood pressure support, it may take several weeks to months. Vitamin K2 takes several weeks to months to show effects on bone and arterial support.