Vitamin K2 Supplements: Compare Forms, Labels & Value

Vitamin K1 vs vitamin K2 (context)

Vitamin K1 (phylloquinone) comes mainly from green leafy vegetables and is the form most dietary reference values are based on. Vitamin K2 (menaquinones) comes from animal-derived and fermented foods and from gut bacteria. Both contribute to normal vitamin K status, but they are different compounds — a K2 supplement is not interchangeable with a K1 supplement on a one-to-one basis.

MK-4 (menaquinone-4)

A short-chain menaquinone found in animal-derived foods and produced in the body from other vitamin K forms. It appears in some supplements, often at milligram-scale doses. Compare the declared MK-4 amount per serving and the documentation behind the product — the form name alone is not a quality verdict.

MK-7 (menaquinone-7)

A longer-chain menaquinone produced by bacterial fermentation and found in fermented foods such as natto. It is the form most commonly used in K2 supplements, typically at microgram-scale doses. Compare the declared MK-7 amount per serving and the documentation behind the product rather than the form claim alone.

Other menaquinones (MK-5, MK-6, MK-8, MK-9, etc.)

Several other menaquinones exist in foods and in some supplements. They are different compounds from MK-4 and MK-7. When a label names a specific menaquinone, compare the declared amount for that form; when a label only says “vitamin K2” without specifying, note that the form is not documented.

D3 + K2 combinations

Many products pair vitamin K2 with vitamin D3 in one softgel or capsule. This is a formulation choice, not an endorsement — see the dedicated Vitamin D hub for how to read the D3 side of the label. Compare the declared K2 amount, the declared D3 amount, and the testing behind the product together.

Softgels, capsules & liquids

A format choice. Because vitamin K2 is fat-soluble, it is usually delivered in an oil-based softgel or liquid rather than a dry tablet. The comparison comes down to vitamin K2 per serving, servings per container, and standardized value.

Vitamin K is well studied in relation to normal blood clotting and bone metabolism, with growing research on the menaquinone (K2) forms. The summary below orients you; it is not a treatment or dosing recommendation, and results vary by population, baseline status, and the form used.

What the research landscape looks like

• Dietary reference values

  The US adequate intake for vitamin K is 120 μg/day for adult men and 90 μg/day for adult women, set for total vitamin K from all forms. EFSA sets an adequate intake of 70 μg/day for adults. These references cover total intake from food and supplements combined and are not specific to K2 form.

• MK-4 vs MK-7

  Most K2 supplement research uses MK-4 or MK-7, which are different compounds with different doses and circulating half-lives. Studies comparing their effects have produced varying results, and no form is established here as superior for any outcome. Compare the declared form and amount per serving rather than assuming one is better.

• Studied outcomes

  Vitamin K2 has been studied for bone and cardiovascular outcomes, among others, often in combination with vitamin D. Results vary by population, dose, and baseline status; no outcome is established here as a supplement effect, and combination products are a formulation consideration, not an endorsement.

• Anticoagulant medication (warfarin and related drugs)

  Vitamin K (including K2) can reduce the effect of warfarin and related anticoagulants, which work by interfering with vitamin K–dependent clotting. People on these medications should not start, stop, or change a vitamin K2 supplement without consulting the prescribing clinician. This is the most important safety consideration for K2.

• Fat-soluble absorption

  Because vitamin K2 is fat-soluble, it is best absorbed with dietary fat. Conditions that reduce fat absorption (such as certain liver, gallbladder, or bowel conditions) can lower vitamin K status; discuss supplementation with a clinician if these apply.

• Pregnancy and medical guidance

  Whether a vitamin K2 supplement is appropriate in pregnancy, while nursing, or alongside any medical condition is a decision for a healthcare professional. This hub does not recommend K2 for any specific situation or outcome.

No single vitamin K2 product is “best” for everyone, and anyone on anticoagulant medication should consult their clinician before choosing. These neutral criteria help you narrow the field to the products worth comparing side by side. They use only the facts HerbParlor already structures and scores — nothing here is influenced by affiliate availability, commission, merchant, or a sponsored ranking.

K2 form (MK-4 / MK-7 where documented)

“Vitamin K2” can mean MK-4, MK-7, or another menaquinone. The form is a label fact, not a quality verdict. Pick the form(s) relevant to your goal, then compare products that name it clearly — and note when a label only says “vitamin K2” without specifying the menaquinone.

Amount per serving

How much vitamin K2 a serving delivers, stated in micrograms (μg) or milligrams (mg). MK-7 products often range from around 45 μg to 180 μg per serving, while MK-4 products may use milligram-scale doses, so compare the declared amount rather than assuming a standard dose.

Serving size

A serving may be one softgel, one capsule, or a measured dose of liquid. Serving size and servings per container decide how many doses you are comparing and how long a bottle lasts — both feed the standardized value.

Formulation & additional ingredients

A clear ingredient list, the carrier oil (such as MCT, olive, or soybean oil), named excipients, and a stated format (softgel, capsule, liquid) are part of HerbParlor’s transparency scoring. Missing or vague disclosure is reported as unavailable, not silently treated as a failure or a pass.

Whether vitamin D is also included

Many K2 products also contain vitamin D3. If a product includes D3, compare both the declared D3 and K2 amounts, and see the Vitamin D hub for reading the D3 side of a combination label. A D3 + K2 combination is a formulation consideration, not an endorsement.

Documented testing & verification

Look for reported third-party testing, a named lab, or certifications such as Informed Sport, NSF, or USP — and note whether that is independent verification or a brand/retailer claim. HerbParlor records testing information as attributed and never upgrades a claim to independent verification.

Manufacturer & source transparency

A named manufacturer, a stated country of origin, and traceable sourcing are part of HerbParlor’s transparency scoring. Products that disclose more are easier to compare; products that disclose less are reported as such, not ranked against them.

Price & value (VitaValue™)

VitaValue™ puts price next to a comparable quantity — cost per standardized unit of vitamin K2 — so serving size, format, and packaging cannot disguise the real cost. Use it to compare value only after the criteria above are acceptable to you.

Enough information to compare?

A meaningful comparison needs the declared vitamin K2 amount, the form, the serving size, and at least some documented testing or sourcing. If a product leaves these blank, it cannot be fairly compared yet — that is a fact about disclosure, not a judgment of the product itself.

1. 01

   Vitamin K2 amount per serving

   How much vitamin K2 a serving delivers, usually stated in micrograms (μg). Compare in a single consistent unit so two products are measured the same way. K2 doses vary — from around 45 μg to 100 μg, 180 μg, or more per serving, and MK-4 products may use milligram-scale doses.

2. 02

   K2 form (MK-4, MK-7, or other menaquinone)

   Which menaquinone form is used and whether the label names it. “Vitamin K2” without a form name is less specific than “MK-7” or “MK-4”. Form specificity is one of HerbParlor’s scored dimensions.

3. 03

   Serving size & servings per container

   A single softgel, capsule, or a measured dose of liquid can each be one serving. Servings per container decides how long a bottle lasts and feeds the standardized value.

4. 04

   Whether vitamin D is also included

   Many K2 products also contain vitamin D3. If so, check the declared D3 amount as well as the K2 amount, and compare both. See the Vitamin D hub for reading the D3 side of a combination label.

5. 05

   Additional ingredients & oil base

   Because K2 is fat-soluble, products usually list a carrier oil (such as MCT, olive, or soybean oil). A clear ingredient list, named excipients, and the oil base are part of HerbParlor’s transparency scoring.

6. 06

   Testing & certifications

   Whether the product reports third-party testing, a named lab, or certifications — and whether that is independent verification or a brand/retailer claim. These are recorded as attributed, never silently upgraded.

7. 07

   Standardized value

   VitaValue™ puts price next to a comparable quantity — cost per comparable unit of vitamin K2 — so format and packaging don’t disguise the real cost.

These are HerbParlor’s existing tools, contextualised for vitamin k2. Each one turns research into a shortlist you can act on — no sponsored rankings, no hidden ordering.

Every product below is a real, canonical record assessed with the same VitaScore™ rubric. Open any product for the full profile, or compare several side by side.

Editorial explainers that break down the labels, the chemistry, and the comparison framework behind this hub.

• How to Compare Supplements

  The general framework behind every HerbParlor comparison.

  Read article

• How to Verify Third-Party Testing

  What independent verification actually means — and what a claim is not.

  Read article

1. 01

   No sponsored rankings. Ever.

   HerbParlor sells nothing and takes no placement fees. Scores cannot be bought, influenced, or negotiated.

2. 02

   Testing information over label claims

   We note when products report third-party testing, and say so when a product reports none. A manufacturer or retailer claim is never treated as independent verification.

3. 03

   Affiliate-neutral

   Commercial relationships do not influence scores, ordering, or what appears on this hub. Retailer links appear only when verified and are kept separate from editorial analysis.

Is MK-7 better than MK-4?

“Better” depends on what you mean and is a decision for you and your clinician. MK-7 and MK-4 are different menaquinone compounds with different typical doses and circulating half-lives. Studies comparing their effects have produced varying results, and no form is established here as superior for any outcome. This hub helps you compare both on declared form, amount, and testing — it does not declare a winner.

Should I take vitamin K2 with vitamin D?

Vitamin K2 is frequently combined with vitamin D3 in one product, and that is a formulation choice, not an endorsement. If you take a D3 + K2 product, compare both the declared D3 and K2 amounts. Whether a combination makes sense for you is a personal decision, ideally made with a healthcare professional — see the Vitamin D hub for reading the D3 side of the label.

How much vitamin K2 is in a serving?

It varies widely. MK-7 products often declare around 45 μg to 180 μg per serving, while MK-4 products may use milligram-scale doses. The serving may be one softgel, one capsule, or a measured dose of liquid. Always read the declared amount, the form, and the serving size together rather than assuming a standard dose.

Can I take vitamin K2 if I am on warfarin or another blood thinner?

Talk to your prescribing clinician first. Vitamin K (including K2) can affect how warfarin and related anticoagulants work, even at microgram-scale doses. People on these medications should not start, stop, or change a vitamin K2 supplement without medical guidance, and should keep vitamin K intake consistent.

Is vitamin K2 the same as vitamin K1?

No. Vitamin K1 (phylloquinone) comes mainly from green leafy vegetables, while vitamin K2 (menaquinones such as MK-4 and MK-7) comes from animal-derived and fermented foods and from gut bacteria. Both contribute to normal vitamin K status, but they are different compounds and a K2 supplement is not interchangeable with a K1 supplement on a one-to-one basis.

Does vitamin K2 help with bones or arteries?

Vitamin K is involved in normal bone metabolism and normal blood clotting, and K2 has been studied for bone and cardiovascular outcomes, often alongside vitamin D. Results vary by population, dose, and baseline status, and no outcome is established here as a supplement effect. Whether a vitamin K2 supplement is appropriate is a decision for a healthcare professional.