Guides›Vitamin K

Vitamin guide

Vitamin K

Vitamin K comes in two main families: K1 and K2. K1 is the main form found in green leafy vegetables and is also used in supplements. K2 includes several forms, of which MK-4 and MK-7 are commonly found in supplements.

Compare products ↓

In this guideIngredient basics, choosing & product comparison

What is vitamin K?

Vitamin K is a family of fat-soluble compounds. Vitamin K1 (phylloquinone) is common in food and is also available in supplements. Vitamin K2 refers to menaquinones, including MK-4 and MK-7, which are also used in supplements.

What does vitamin K support?

Vitamin K contributes to normal blood clotting and the maintenance of normal bones. These functions apply to vitamin K as a nutrient, rather than being separate authorised benefits for K1, MK-4 or MK-7.

What happens if you don’t get enough vitamin K?

Severe vitamin K deficiency reduces the activity of vitamin K-dependent clotting factors and can cause easy bleeding or haemorrhage. Clinically significant deficiency is very rare in healthy adults eating a varied diet and is more likely with severe malabsorption or medicines that interfere with vitamin K metabolism.

Vitamin K and anticoagulants need special care

Vitamin K has an important interaction with vitamin K antagonist medicines such as warfarin. People using these medicines should follow their healthcare professional’s advice rather than making large, sudden changes in vitamin K intake or supplements.

How much vitamin K?

The EU label NRV for vitamin K is 75 µg. % NRV helps put the labelled amount into context, while the form — K1, MK-4 or MK-7 — is a separate product characteristic.

K1, MK-4 or MK-7?

Vitamin K1 (phylloquinone) and vitamin K2 forms such as MK-4 and MK-7 all appear in supplements. MK-7 is especially common in K2 products and in vitamin D + K combinations. For shoppers, the useful distinctions are the declared form, daily vitamin K amount and whether the product is standalone or part of a combination formula.

Why MK-7 stands out on labels

MK-7 has a longer circulating half-life than K1 in pharmacokinetic studies, which helps explain its prominence in supplement products. The authorised EU benefit claims still apply to vitamin K rather than creating a separate health claim for MK-7.

What should you compare?

Vitamin K / day

Compare the amount supplied by the recommended daily serving.

Form

Check whether the label specifies K1 (phylloquinone), K2 MK-4 or K2 MK-7.

Standalone or combination

Vitamin K is often paired with vitamin D, especially in bone-focused products.

Format

Tablets, capsules and liquids can differ in dose and serving pattern.

Good to know: Vitamin K can interact importantly with vitamin K antagonist anticoagulants such as warfarin. If you use these medicines, follow your healthcare professional's advice about vitamin K intake and supplements.

Product comparison

Compare vitamin K supplements

Compare vitamin K per day, K1 or K2 form, source information, format and vegan suitability.

Compare the labelled vitamin K form and daily amount. Products may use vitamin K1 (phylloquinone) or vitamin K2 forms such as menaquinone-4 (MK-4) and menaquinone-7 (MK-7), or combinations. Vitamin K EU Nutrient Reference Value (NRV): 75 µg for adult labelling; it is a labelling reference, not a personal dose recommendation.

Product	Vitamin K / day	Vitamin K / unit	Form	Source / all-trans info	Format	Vegan
Solgar Vitamin K2 100 µgView product ↗	100 µg	100 µg	MK-7	Naturally sourced MK-7	Vegetable capsule	No / contains milk
Viridian Vitamin K2 100 µgView product ↗	100 µg	100 µg	MK-7	Fermented Bacillus subtilis natto cultures; extracted in Italy	Plant cellulose capsule	Yes
NOW Foods MK-7 Vitamin K-2View product ↗	100 µg	100 µg	MK-7	MenaQ7®	Veg capsule	Yes
Life Extension Super KView product ↗	3,180 µg total labelled vitamin K forms	2,000 µg K1 + 1,000 µg MK-4 + 180 µg MK-7	K1 + K2 MK-4 + K2 MK-7	MK-7 as MenaQ7® trans menaquinone-7	Softgel	No
Sunday Natural Vitamin K2 MK-7 200 µgView product ↗	200 µg	200 µg	K2 MK-7	K2VITAL®; ≥99.7% all-trans	HPMC capsule	Yes

EU health claims: Vitamin K contributes to normal blood clotting and the maintenance of normal bones. Supplements may use K1 or K2 forms such as MK-4 and MK-7.

Medicine interaction: vitamin K can interact with coumarin-type anticoagulants. People using these medicines should seek medical advice before changing vitamin K intake.

EU health claim details

✓

Authorised health claims

EU-authorised health claims (Article 13)

2 authorised

● Vitamin K contributes to normal blood clotting.Blood clotting · General population

Claim type
Health functions (Article 13)

Condition of use
The claim may be used only for food which is at least a source of vitamin k.

What does “source of” usually mean?
General food: 11.25 µg / 100 g or 100 ml
Beverage: 5.625 µg / 100 ml
Single-portion pack: 11.25 µg per portion
Calculated from the EU NRV significant-amount reference. Claim-specific conditions take precedence.

EFSA / scientific assessment
EFSA opinion reference listed in the EU Register / Regulation (EU) No 432/2012

EU legal source
Commission Regulation (EU) No 432/2012 (consolidated 20 Aug 2025)

● Vitamin K contributes to the maintenance of normal bones.Bones · General population

Claim type
Health functions (Article 13)

Condition of use
The claim may be used only for food which is at least a source of vitamin k.

EFSA / scientific assessment
EFSA opinion reference listed in the EU Register / Regulation (EU) No 432/2012

EU legal source
Commission Regulation (EU) No 432/2012 (consolidated 20 Aug 2025)

Other assessed health claims (2)

Not authorised for use in the EU

View claims ↓

A non-authorised claim is not automatically the same as a scientifically disproven claim. Open a claim to see the recorded reason or source details where available.

● Vitamin K1 and K2 supports a healthy heart. Vitamin K1 and K2 stimulates blood clotting.Heart and blood vessels ·

Claim type
Health functions (Article 13)

Condition of use
—

EFSA / scientific assessment
EFSA Journal 2009;7(9):1228

EU legal source
—

Additional statement / restriction
Non-compliance with the Regulation because on the basis of the scientific evidence assessed, the evidence provided is insufficient to substantiate this claimed effect for this food.

● MK-7 is a highly bioavailable form of vitamin K that helps maintain a healthy cardiovascular system / helps keep the heart and blood vessels healthy.Heart and blood vessels ·

Regulatory details

Check how the claims on this page are classified and where their regulatory information comes from.

View page-level details

Ingredient: Vitamin K
Category: Vitamin
NRV: 75 µg
Authorised claims: 2
Other assessed claims: 2
Claim framework: EU nutrition and health claims framework. Individual claim cards show the specific claim type, conditions of use, EFSA reference and legal source available in the version data.

Tip: expand any claim above for its claim-specific source details. The European Commission's EU Register is an information service; legal acts are the authoritative source for legal requirements, and some pending claims are not shown in the Register.

Claim use requirements

How much of this nutrient must a food contain for an EU health claim to be used?

For claims requiring the food to be a source of Vitamin K, the usual NRV-based significant amount is:

11.25 µg / 100 g or 100 ml for foods other than beverages
5.625 µg / 100 ml for beverages
11.25 µg per portion if the package contains only one portion

These are the general EU significant-amount reference levels. A claim-specific condition may be stricter and takes precedence.

Vitamin K

What is vitamin K?

What does vitamin K support?

What happens if you don’t get enough vitamin K?

How much vitamin K?

K1, MK-4 or MK-7?

What should you compare?

Vitamin K / day

Form

Standalone or combination

Format

Compare vitamin K supplements

Authorised health claims

Other assessed health claims (2)

Regulatory details

Claim use requirements

Sources

Sources & further reading