Vitamin K1 vs. Vitamin K2: The Clotting Factor vs. The Bone and Artery Regulator

Short answer: Vitamin K1 (phylloquinone) is primarily responsible for blood clotting, while Vitamin K2 (menaquinone) is critical for bone and arterial health, directing calcium to the right places. Practical advice: For athletes, the focus should be on Vitamin K2 (MK-7 form) in doses of 100–200 mcg daily for healthy bones. Combine it with adequate intake of K1 from food (spinach, broccoli) and Vitamin D3.

Vitamin K is a fat-soluble vitamin that is key to health, especially for active individuals. It often goes unnoticed compared to more well-known vitamins like D or C, but its role is important for athletes. To optimize recovery, bone strength, and cardiovascular function, it's important to understand the differences between the two main forms of vitamin – K1 (phylloquinone) and K2 (menaquinone).

Vitamin K1 is primarily responsible for a quick response to injury. It activates the proteins that clot blood, thus stopping bleeding. Without it, even a small cut would be a serious problem. Vitamin K2 works in the long term. It directs calcium to bones and teeth and ensures it doesn't accumulate where it can cause harm – for example, in arteries and soft tissues.

For athletes, this combination is very important. K1 ensures quick recovery from injuries, while K2 builds a strong bone system that can withstand the loads of intense training. K2 also keeps arteries elastic. Differentiating them is of practical importance for anyone who wants to achieve high results in sports and maintain their health for a long time.

This article is part of the Expert Hub for Food Supplements — over 270 expertly verified articles by Petar Mitkov and the Sport Zona team.

What is the difference between K1 and K2?

Criterion	Vitamin K1 (Phylloquinone)	Vitamin K2 (Menaquinone)
Primary Focus	Blood clotting (coagulation)	Calcium distribution (bones and arteries)
Primary Organ of Action	Liver	Bones, blood vessels, soft tissues
Mechanism of Action	Activates blood clotting factors	Activates osteocalcin and matrix Gla-protein (MGP)
Main Dietary Sources	Leafy green vegetables (spinach, kale, broccoli)	Fermented foods (natto), hard cheeses, meat, egg yolks
Time Horizon (Half-life)	Short (approx. 1.5 hours)	Long (various forms, MK-7 up to 72 hours)
Important for Athletes	Rapid recovery from injuries, prevention of bleeding	Bone health, cardiovascular system, muscle function

Expert Note: Why are both types important?

Vitamin K1 and Vitamin K2 perform different roles. K1 is important for blood clotting, primarily in the liver. K2 is more for the long-term health of bones and the cardiovascular system, helping with the proper distribution of calcium in the body.

You cannot rely on just one type to get the benefits of the other. These vitamins have their specific functions. For example, if you are looking for strong bones and clear arteries, K2 is more effective. If the problem is with blood clotting, K1 is your helper.

For athletes, combining these vitamins is very beneficial. K1 prepares the body for rapid recovery from potential injuries, and K2 strengthens the bone structure and supports cardiovascular health, which is important for long-term activity.

Want to eat better?

Discover your diet plan, created by a nutritionist, with a one-time payment and lifetime access. Get a Personal Consultation and an Individual Plan tailored to your needs and goals!

Get your plan now!

How are Vitamin K1 and K2 taken and dosed?

Vitamin K1 and K2 are taken according to individual needs and specialist recommendations, with K1 known for its clotting factor and K2 for its role as a bone and arterial regulator.

Vitamin K1

• Recommended Daily Intake (RDI): For adult men, around 120 µg; for women, 90 µg.
• Sources: Rich sources of K1 include leafy greens like spinach, kale, broccoli, and parsley.
• Absorption: K1 is fat-soluble, so it is absorbed better when consumed with fats (e.g., a salad with olive oil).

Vitamin K2

• Recommended Daily Intake (RDI): There is no precise RDI, but studies show benefits with an intake of 100-300 µg daily, especially in the MK-7 form.
• Sources: The richest source is fermented soybean dish natto, but it is also found in egg yolks, cheeses (Gouda, Edam), and meat.
• Forms: K2 has several forms called menaquinones (MK-n). The most common and well-studied are MK-4 and MK-7. MK-7 has a longer half-life and is more bioactive.

Combined Intake

• Many supplements combine K2 with Vitamin D3, as they work together for calcium metabolism. D3 helps with calcium absorption, and K2 directs it to the right places.
• Always consult a doctor or dietitian before starting any supplements, especially if you are taking anticoagulants, as Vitamin K can interact with them.

Which is more important: Vitamin K1 or K2 for active individuals?

Vitamins K1 and K2 are vital for athletes, with K1 primarily involved in blood clotting, while K2 regulates calcium in bones and arteries.

• K1 is key for rapid blood clotting, which aids in injuries.
• K2 is important for long-term bone and cardiovascular health.

For athletes seeking a complete package of benefits, they can combine dietary sources and supplements containing both vitamins. This will support recovery, strengthen bones, and maintain a healthy cardiovascular system. Always remember that a balanced diet is the foundation, and supplements build upon the nutritional regimen.

About the Author

Petar Mitkov is a Master Pharmacist and founder of SportZona. With over 10 years of experience in food supplements and sports nutrition, he actively works on the dosing and safety of products, as well as on personalized nutrition plans. His knowledge forms the basis of every article in SportZona Academy, providing readers with scientifically based and practical information.

Information Sources

• Gast GC, et al. A High Mennagerie of Vitamins K: Dietary Intake and Circulating Concentrations of Phylloquinone and Menaquinones in the Rotterdam Study. Adv Nutr. 2012 Nov 1;3(6):838-47.
• Schurgers LJ, et al. Vitamin K: The key to vascular calcification. J Thromb Haemost. 2008 Jul;6(7):1074-80.
• Schwalfenberg GK. Vitamins D and K as Pleiotropic Nutrients: Clinical Implications for Skeletal, Cardiovascular, and Cancer Health. J Nutr Metab. 2015;2015:378036.
• Halder M, et al. Vitamin K: An Important Cofactor for Bone Metabolism and Vascular Health. Adv Nutr. 2019 Mar 1;10(2):S105-S117.