Vitamin K3 (Menadione): Dosage, Timing & Interactions

Check it against something

Evidence level B

Vitamin K3 (Menadione) with:

70 out of 100

Needs attention Separate by 2-4 hours to avoid the interaction below.

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What it does

mechanism and evidence for each claim

High potency and bioavailability

More potent than natural vitamin K forms

Synthetic form with enhanced cellular uptake Evidence B-grade Rapid onset

Enhanced vitamin K activity

Superior vitamin K effects compared to natural forms

Direct conversion to active vitamin K forms Evidence B-grade Hours to days

Research applications

Valuable for vitamin K research and specialized medical uses

Consistent potency and known pharmacokinetics Evidence A-grade Variable

Overcoming deficiency rapidly

Can quickly correct severe vitamin K deficiency

High bioavailability and potent activity Evidence B-grade Hours to days

Every pair we checked

12 combinations scored by the engine

Vitamin K3 (Menadione) + Vitamin D3 High vitamin E may interfere with vitamin K function Needs attention 70

Vitamin K3 (Menadione) + Caffeine No documented interaction either way No known interaction 70

Vitamin K3 (Menadione) + Creatine Monohydrate No documented interaction either way No known interaction 70

Vitamin K3 (Menadione) + Whey Protein No documented interaction either way No known interaction 70

Vitamin K3 (Menadione) + Turmeric No documented interaction either way No known interaction 70

Vitamin K3 (Menadione) + Vitamin C (Ascorbic Acid) High vitamin E may interfere with vitamin K function Needs attention 74

Vitamin K3 (Menadione) + Vitamin B12 (Methylcobalamin) High vitamin E may interfere with vitamin K function Needs attention 74

Vitamin K3 (Menadione) + Lactase Improved calcium absorption when consuming dairy Works better together 82

Vitamin K3 (Menadione) + Bovine Collagen Essential for collagen synthesis and cross-linking Works better together 82

Vitamin K3 (Menadione) + DHA Prevents oxidation of DHA and enhances stability Works better together 82

Vitamin K3 (Menadione) + Fish Oil (EPA/DHA) Protects fish oil from oxidation Works better together 90

Vitamin K3 (Menadione) + Calcium Carbonate Essential for calcium absorption and utilization Works better together 94

Dosage

Research protocols only

DailyNot recommended for human use

Human consumptionNot recommended

Research protocolsVariable, research only

Veterinary useSpecies-specific protocols

Safety limitAvoid for human supplementation

Before you take it

Restricted substance. Synthetic menadione — banned from sale as a supplement in the US and EU.

VeganYes

When to expect it

First EffectsHours for vitamin K activity

Peak BenefitsDays to weeks depending on application

Deficiency DevelopmentSame as other vitamin K forms

Toxicity OnsetCan be rapid with overdose

How to measure it

$40-100

MarkerProthrombin time (PT), INR, or vitamin K status

OptimalNormal clotting times

FrequencyNot applicable for human supplementation

Not recommended for human use regardless of test results

What people actually reported to the FDA

CAERS, 33 reports naming it as the suspect

Most reported effects

Pain 3

Chest pain 3

Death 3

Nephrolithiasis 3

Atrial fibrillation 3

Named as the suspect 33 reports of 92 that mention it at all

Serious outcome 85% hospitalisation, emergency room or worse

Other Serious or Important Medical Event21

Hospitalization17

Visited Emergency Room8

Reports are voluntary and unverified — they record what someone experienced while taking something, not what the compound caused. Counts skew towards products people take a lot of, and a serious outcome is more likely to be reported than a mild one, so these are not rates. How we filter them →

Works better with

2 documented

+

Vitamin D

Both required for proper calcium utilization

D3 produces proteins that vitamin K activates · level A (for vitamin K generally)

+

Vitamin A

Balance needed for optimal function

Both fat-soluble vitamins with gene regulation roles · level B (theoretical for K3)

What not to take with Vitamin K3 (Menadione)

2 documented

!

Vitamin E Excess

High vitamin E may interfere with vitamin K function

Interference with vitamin K recycling · moderate significance

!

Antioxidants Excess

May counteract pro-oxidant effects but also benefits

Reduction of both harmful and beneficial oxidative effects · complex significance

Medication interactions

Discuss these with a pharmacist before combining

warfarin-anticoagulants Major

Extremely potent interaction, can be dangerous

What to do: Avoid completely with anticoagulant therapy

antibiotics Minor

May affect gut bacteria vitamin K production

What to do: Not relevant as K3 not recommended for human use

Available forms

bioavailability compared

Menadione (Vitamin K3) 95

Menadione (Vitamin K3): High potency, Enhanced bioavailability, Research applications, Rapid action

Food sources

before you supplement

Menadione not found naturally in foods Synthetic compound only · 95

Natural vitamin K1 and K2 in foods are safer alternatives Variable natural vitamin K content · 80

Too little

deficiency signs

Same as vitamin K deficiency:
Bleeding and bruising
Poor bone mineralization
Arterial calcification
Delayed blood clotting
Note: K3 not recommended for treating deficiency

Too much

toxicity signs

Hemolytic anemia
Liver damage and jaundice
Kernicterus in infants
Oxidative tissue damage
Altered blood clotting
Potential carcinogenic effects

Who benefits most

research-applications-only

Primarily used in scientific research settings

Variable, research protocols only

veterinary-use

Used in animal nutrition and veterinary medicine

Veterinary protocols only

not-recommended-human-consumption

Safety concerns and regulatory restrictions

Not recommended

How it works

Converted to vitamin K1 and K2 in tissues
More potent vitamin K activity than natural forms
Enhanced cellular uptake and bioavailability
Can generate reactive oxygen species
Direct cofactor for vitamin K-dependent enzymes
May have pro-oxidant effects at higher doses

Key findings

what the evidence supports

Higher potency than natural vitamin K forms (established)
Potential for toxicity at higher doses (documented)
Banned for human consumption in many countries (regulatory)
Useful for research applications requiring consistent vitamin K activity

Sources: NIH Examine.com · data reviewed 2026-08-02

Compiled by Denis, who maintains this database and holds no medical qualification — every figure here is sourced or derived, never asserted. How we calculate it →

Common questions

What are the benefits of Vitamin K3 (Menadione)?

Documented effects: High potency and bioavailability; Enhanced vitamin K activity; Research applications; Overcoming deficiency rapidly. More potent than natural vitamin K forms

How much Vitamin K3 (Menadione) should you take per day?

The common daily range is Not recommended for human use. By goal — human consumption: Not recommended; research protocols: Variable, research only; veterinary use: Species-specific protocols; safety limit: Avoid for human supplementation.

When is the best time to take Vitamin K3 (Menadione)?

Research protocols only. First effects are typically reported within Hours for vitamin K activity.

What are the side effects of Vitamin K3 (Menadione)?

At excessive doses: Hemolytic anemia, Liver damage and jaundice, Kernicterus in infants, Oxidative tissue damage, Altered blood clotting. Safety rating at normal doses is 3 out of 10.

What should you not take with Vitamin K3 (Menadione)?

Separate it from Vitamin E Excess, Antioxidants Excess by two to four hours. High vitamin E may interfere with vitamin K function

Does Vitamin K3 (Menadione) interact with medications?

Documented interactions with warfarin-anticoagulants, antibiotics. Discuss these with a pharmacist before combining.

How do you know if you need Vitamin K3 (Menadione)?

The marker is Prothrombin time (PT), INR, or vitamin K status, optimal range Normal clotting times. Common deficiency signs: Same as vitamin K deficiency:, Bleeding and bruising, Poor bone mineralization, Arterial calcification.