How much vitamin K2 can I have per day?

December 31, 2025 •

3 min read

While no official Recommended Dietary Allowance (RDA) has been established for vitamin K2 specifically, many health experts and studies suggest a daily intake ranging from 100 to 300 micrograms for adults to support optimal bone and cardiovascular health. This fat-soluble vitamin plays a crucial role beyond just blood clotting, impacting calcium metabolism significantly.

Quick Summary

Optimal vitamin K2 intake, primarily in the MK-7 form, is often cited between 100-200 mcg daily for adults, although there is no formal upper limit due to its high safety profile. It works synergistically with vitamin D3 and is vital for directing calcium to bones and away from arteries. Doses for specific conditions, like osteoporosis, may differ.

Key Points

No Official UL: Regulatory bodies have not set a tolerable upper intake level for vitamin K2 due to its high safety profile and low risk of toxicity.
Suggested Daily Intake: A range of 100-200 mcg per day of the MK-7 form is commonly suggested for healthy adults to support bone and heart health.
Synergy with Vitamin D3: Vitamin K2 works best alongside vitamin D3, helping to direct absorbed calcium to bones and prevent arterial buildup.
Watch for Drug Interactions: Individuals taking blood-thinning medications, such as warfarin, must consult a doctor before supplementing with vitamin K2, as it can affect coagulation.
MK-4 vs. MK-7: MK-7 (longer half-life) is generally favored for consistent benefits, while MK-4 (shorter half-life) may require higher doses, especially for targeted therapeutic use.
Consider Supplements: Since dietary sources of K2 can be inconsistent, supplementation with a high-quality MK-7 product is often the most reliable way to achieve optimal intake.

Understanding Vitamin K2: Forms and Functions

Vitamin K encompasses two main types: K1 (phylloquinone) and K2 (menaquinones). K1, found in leafy greens, primarily aids blood clotting. K2, present in fermented foods and some animal products, is crucial for directing calcium into bones and preventing its accumulation in soft tissues like arteries. K2 exists in different forms (MK-4, MK-7, etc.), with MK-7 noted for its longer half-life and sustained benefits for bone and cardiovascular health.

General Dosage Recommendations for Adults

While there's no official RDA for vitamin K2, suggested daily intakes for healthy adults typically focus on the MK-7 form to activate essential proteins. A common recommendation for general health and bone/cardiovascular support is 100 to 200 mcg of vitamin K2 (MK-7) daily. Some research on cardiovascular benefits has used doses like 180 mcg daily. MK-4 often requires much higher doses, with some osteoporosis studies in Japan using up to 45 mg (45,000 mcg) daily.

Is There a Tolerable Upper Limit?

Both the European Food Safety Authority and the National Institutes of Health report no established tolerable upper intake level (UL) for vitamin K1 or K2 due to a lack of evidence of toxicity from high doses. Studies, even with high oral doses of MK-4, have shown good tolerance in healthy individuals without negative effects on blood coagulation.

The Synergy with Vitamin D3

Vitamin K2 and vitamin D3 work together. Vitamin D3 increases calcium absorption, and vitamin K2 helps ensure that calcium is deposited in bones and not in arteries, by activating proteins like osteocalcin and Matrix Gla Protein. Combining D3 and K2 is often recommended, especially with higher D3 doses, to help prevent calcium buildup in soft tissues.

Special Considerations and Drug Interactions

Individuals taking anticoagulant medications like warfarin should be cautious, as vitamin K directly interferes with their action. Consulting a doctor is essential before starting K2 supplementation if on warfarin. Interactions are also possible with certain antibiotics and cholesterol-lowering drugs. Those with conditions affecting vitamin K absorption may need different dosages.

K2 Supplements vs. Dietary Sources

Getting enough vitamin K2 from food can be difficult, as rich sources are not common in all diets. This makes supplementation a practical option.

Comparison Table: Dietary vs. Supplemental K2


Feature	Dietary K2 (e.g., Natto, cheese)	Supplemental K2 (e.g., MK-7 capsules)
Convenience	Variable; requires consistent intake of specific foods.	High; easy to take a standardized dose daily.
Dosage Control	Difficult to measure exact intake from food.	Precise and reliable dosage per capsule.
Bioavailability	Depends on food source; long-chain MK-7 from fermented foods is highly bioavailable.	High, especially with oil-based softgels.
Form	Mixed forms (MK-4, MK-7, etc.); proportions vary.	Can be specific forms, most commonly MK-7 or a blend.
Consistency	Varies with diet, making consistent intake hard.	Reliable and consistent intake daily.
Cost	Can be more expensive, depending on food choices.	Generally more cost-effective for a therapeutic dose.

Conclusion: Finding Your Optimal K2 Intake

While there isn't a universal daily recommendation, 100-200 mcg of MK-7 is often suggested for healthy adults for bone and cardiovascular health. Vitamin K2 has an excellent safety profile, with minimal risk of toxicity even at high intakes in healthy individuals. However, those on blood-thinners like warfarin must use K2 supplements under strict medical guidance. Combining K2-rich foods with a quality MK-7 supplement, often with vitamin D3, can support health. Always consult a healthcare provider for personalized advice.

Frequently Asked Questions

Vitamin K1 (phylloquinone) is found in leafy green vegetables and is primarily involved in blood clotting. Vitamin K2 (menaquinones) is found in animal products and fermented foods, with a greater focus on regulating calcium in bones and arteries.

While it is possible, it can be challenging, especially in Western diets. The richest source is natto (fermented soybeans), but other sources include grass-fed dairy, egg yolks, and organ meats. For consistent intake, particularly the potent MK-7 form, many people opt for supplements.

The MK-7 form of vitamin K2 is often recommended because it has a longer half-life, meaning it stays in your body longer and is more consistently available to benefit tissues like bones and arteries. Look for MK-7 sourced from natural fermentation.

For most healthy individuals, it is highly unlikely to consume a toxic amount of vitamin K2 from food or supplements. There is no established tolerable upper intake level due to a lack of evidence of harm, even at high doses.

Vitamin K2 helps with bone health by activating proteins that bind calcium to the bone matrix, and it supports cardiovascular health by preventing calcium accumulation in arteries and blood vessels. It also supports dental health and brain function.

Individuals taking blood-thinning medication (anticoagulants), such as warfarin, must consult a doctor before supplementing with vitamin K2. The vitamin directly impacts blood clotting and can interfere with the medication's effectiveness.

Yes, many health experts recommend taking vitamin K2 with vitamin D3. Vitamin D3 enhances calcium absorption, and vitamin K2 ensures that the calcium is properly directed to the bones, preventing its accumulation in soft tissues.

Side effects are rare and typically mild, such as upset stomach or diarrhea. Serious side effects or toxicity have not been reported from oral intake of vitamin K2 in healthy individuals.