What is Vitamin K2 (K2 Vitamin)?
Vitamin K2 (menaquinones) is a fat-soluble vitamin essential for the gamma-carboxylation of vitamin K-dependent proteins (clotting factors, osteocalcin, matrix Gla protein). It exists in forms ranging from MK-4 to MK-7 depending on the side chain length; MK-7 stands out in supplements due to its long half-life. Unlike K1 (phylloquinone), it remains in tissues for a longer period.
- CAS number (main form): 2124-57-4
- Molecular formula: C₄₆H₆₄O₂
- Forms in the catalog: Menaquinone, Seebio, Menaquinone, Guangdong
What is K2 Vitamin Used For? Why is it Used?
Vitamin K2 ensures the function of K-dependent proteins necessary for normal blood clotting and bone health (both are EFSA-approved claims). In supplements, MK-7 is preferred due to its long half-life and superior bioavailability compared to MK-4, making it suitable for once-daily dosing. The fact that EFSA has not established an UL for vitamin K indicates a wide safety margin; however, caution is required in those using anticoagulants.
Forms and Differences
Vitamin K2 is available in different chemical forms; form selection is made based on bioavailability, stability, and intended use:
- Menaquinone-7 (MK-7): A long side-chain K2 form (usually from natto/bacterial fermentation). With a half-life of approximately 3 days, it stays in the blood for a long time and is suitable for once-daily use; it has shown significantly superior bioavailability compared to MK-4 in healthy women. It is the main form in the catalog.
- Menaquinone-4 (MK-4): A short side-chain K2 form; its half-life is very short (approximately 1–2 hours), and its contribution to serum K levels at dietary amounts is limited. Achieving effective serum levels usually requires divided/higher doses throughout the day.
- Phylloquinone (K1) — comparison: A plant-based K1 vitamin form (for informational purposes). It is primarily used in the liver for clotting factors; K2 (menaquinones) are more effectively utilized in extra-hepatic and vascular tissues.
Use in Food Supplements
- Form used: MK-7 is predominantly used in supplements; due to its long half-life (approximately 3 days) and high bioavailability, a single daily dose is sufficient. The MK-4 form has a shorter duration of action.
- Dosage and unit: Expressed in µg; NRV is 75 µg. MK-7 supplements are typically formulated in the range of 45–180 µg. EFSA has not established a Tolerable Upper Intake Level (UL) for vitamin K.
- For whom: Used for those wishing to support bone health and individuals with low K2 intake; it is often found in products combined with D3 (based on the logic of directing calcium utilization).
- Important warning: Vitamin K can alter the drug effect in individuals using K-antagonist anticoagulants such as warfarin; these individuals should not take K2 without consulting a doctor.
Use in the Food Industry
- Fortification: MK-7 is used in functional foods, dairy products, and food supplements with a bone health positioning; it is generally formulated together with D3.
- Stability and encapsulation: MK-7 may be sensitive to heat and high pH; for stability in food matrices, oil-based carriers, microencapsulation, and high-purity (all-trans) standardized raw materials are used.
- Authorized vitamin source: Menaquinone (K2) and phylloquinone (K1) are among the authorized vitamin K sources in EU food supplement legislation.
Effects on Health
Vitamin K2 is a vitamin that plays a role in many fundamental functions in the body. Its main authorized/evaluated functions by the European Food Safety Authority (EFSA):
- Normal blood clotting: Vitamin K contributes to normal blood clotting (EFSA-approved health claim); it is necessary for the gamma-carboxylation of clotting factors.
- Normal bones: Vitamin K contributes to the maintenance of normal bones (EFSA-approved); it supports the bone matrix through the carboxylation of osteocalcin.
- Activation of Gla-proteins: Vitamin K acts as a cofactor for the functional activation of K-dependent proteins such as osteocalcin and matrix Gla protein (the biochemical basis for bone and clotting claims).
- Deficiency state: Vitamin K deficiency is associated with clotting disorders and bleeding tendency; it demonstrates its central role in clotting.
Usage Limits in Food Supplements
- Nutrition Reference Value (NRV): NRV (1169/2011, Annex XIII): Vitamin K 75 µg.
- Upper Intake Level (EFSA): EFSA UL: There is NO established Tolerable Upper Intake Level (UL) for vitamin K (no numerical UL was derived due to insufficient data).
- Turkish legislation (TETGK): Within the scope of the Turkish Food Supplements Regulation, vitamin K is an authorized vitamin and must be declared on the label in µg/NRV%; for the exact maximum amount per product, current Regulation annexes and TITCK guidelines should be taken as reference (a single official number could not be confirmed in this research — no fabricated value has been provided).
It is fat-soluble but has low known toxicity and EFSA has not established an UL. The most important warning is drug interaction: those using K-antagonist anticoagulants (e.g., warfarin) should not use it without medical supervision.
Technical Specifications
| Parameter | Value |
|---|---|
| Purity | ≥1.0% |
| Appearance | Light yellow oily liquid |
| Moisture | ≤5.0 % |
| Solubility | Fat Soluble |
Scientific Studies
The following independent researches relate to the bioavailability, use, and effects of this vitamin (study types are specified):
- PubMed 23140417 — Comparison of bioavailability of menaquinone-4 and menaquinone-7 in healthy women (clinical study)
- PubMed 32178658 — Effects of MK-7 on bone quality and strength (review)
Technical Documents and Supply — Asuka Kimya
You can contact Asuka Kimya for SDS, TDS, CoA and supply conditions for Vitamin K2.
References
- efsa.onlinelibrary.wiley.com
- ods.od.nih.gov
- eur-lex.europa.eu
- pubmed.ncbi.nlm.nih.gov
- pubmed.ncbi.nlm.nih.gov
The usage and health information on this page has been compiled from official legislation/institution sources (EFSA, NIH ODS, Turkish Food Codex, EUR-Lex) and independent scientific publications (PubMed). The product is a food supplement/food raw material and is not intended for the diagnosis or treatment of disease.