Vitamin K2

Vitamin K2 (menaquinone) is a form of the fat-soluble vitamin K, which contributes to the maintenance of normal bones and to normal blood clotting. There is relatively little of it in the diet – mainly in fermented foods and some mature cheeses – so it is often taken as a food supplement, on its own or in combination with vitamin D3.

In the Vitamin K2 category at ApotekaOnline you will find capsules and tablets with vitamin K2 in the MK-7 form, as well as combinations of vitamins K2 and D3. For single-ingredient vitamin D products, take a look at the Vitamin D category, and for complete bone support the Osteoporosis – calcium, vitamin D and K2 category. You will find combination mineral products in the Calcium, magnesium, zinc and D3 category, and the full range in the Vitamins and minerals category.

What vitamin K2 is and how it differs from vitamin K1

The name vitamin K covers several related compounds. Vitamin K1 (phylloquinone) is found in green leafy vegetables and is the most common form in the diet. Vitamin K2 (menaquinones) includes several forms labelled MK-4 to MK-13, and the form most often used in food supplements is MK-7, which is obtained by fermentation and stays in the blood longer than the other forms, so it is taken once a day.

The reference daily intake of vitamin K for adults, used on labels in the EU, is 75 µg. As foods rich in vitamin K2 are not part of the usual diet in Serbia, a food supplement is a convenient way to get this form of the vitamin regularly.

Vitamins D3 and K2 together: why they are combined

Vitamin D contributes to normal absorption and utilisation of calcium, and vitamin K contributes to the maintenance of normal bones. That is why these two vitamins are often found in the same product – “D3 + K2” is one of the most sought-after combinations among food supplements for bones. Both vitamins are fat-soluble, so they are best taken with a meal that contains a little fat.

If you already take vitamin D, you do not necessarily have to replace it with a combination product – vitamin K2 on its own can be taken alongside your existing product. It is important to add up the total daily amounts from all the products you use and to follow the manufacturer's instructions. A combination with calcium and magnesium is common among menopausal women and older people, for whom preserving bone mass is especially important.

Contraindications and safe use of vitamin K2

The most important note concerns people who take anticoagulant medicines from the vitamin K antagonist group, such as warfarin and acenocoumarol. Vitamin K, including K2, can reduce the effect of these medicines and change INR values. That is why people on anticoagulant therapy should not start, stop or change the dose of vitamin K2 without agreeing this with their doctor. A doctor's advice is also needed when using other anticoagulants and antiplatelet medicines.

Pregnant and breastfeeding women, as well as people with liver disease or blood clotting disorders, should consult a doctor or pharmacist before use. Vitamin K2 is generally well tolerated; if you notice any adverse reactions, stop using it and contact a healthcare professional. Do not exceed the recommended daily dose and keep the product out of the reach of children.