Vitamin K1 (Phylloquinone): Dosage, Timing & Interactions

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Evidence level A

Vitamin K1 (Phylloquinone) with:

74 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

Blood clotting support

Essential for synthesis of clotting factors II, VII, IX, X

Cofactor for gamma-carboxylation of clotting proteins Evidence A-grade 24-48 hours

Wound healing

Promotes proper wound closure and healing

Enables formation of functional clotting factors Evidence A-grade 1-3 days

Bone health support

Contributes to bone protein synthesis

Activates osteocalcin (though less efficiently than K2) Evidence B-grade 4-8 weeks

Cardiovascular support

May help with vascular health

Partial activation of matrix Gla protein Evidence C-grade 8-12 weeks

Antioxidant activity

Provides some antioxidant protection

Direct free radical scavenging Evidence B-grade 2-4 weeks

Every pair we checked

12 combinations scored by the engine

Vitamin K1 (Phylloquinone) + Vitamin D3 High doses may interfere with K function Needs attention 70

Vitamin K1 (Phylloquinone) + Caffeine No documented interaction either way No known interaction 70

Vitamin K1 (Phylloquinone) + Creatine Monohydrate No documented interaction either way No known interaction 70

Vitamin K1 (Phylloquinone) + Whey Protein No documented interaction either way No known interaction 70

Vitamin K1 (Phylloquinone) + Turmeric No documented interaction either way No known interaction 70

Vitamin K1 (Phylloquinone) + Vitamin C (Ascorbic Acid) High doses may interfere with K function Needs attention 74

Vitamin K1 (Phylloquinone) + Vitamin B12 (Methylcobalamin) High doses may interfere with K function Needs attention 74

Vitamin K1 (Phylloquinone) + Vitamin B12 (Cyanocobalamin) High doses may interfere with K function Needs attention 74

Vitamin K1 (Phylloquinone) + Lactase Improved calcium absorption when consuming dairy Works better together 82

Vitamin K1 (Phylloquinone) + Bovine Collagen Essential for collagen synthesis and cross-linking Works better together 82

Vitamin K1 (Phylloquinone) + DHA Prevents oxidation of DHA and enhances stability Works better together 82

Vitamin K1 (Phylloquinone) + Calcium Carbonate Both involved in bone protein function Works better together 99

Dosage

With fat meal

Daily90-120 mcg

Maintenance90-120 mcg

Therapeutic200-500 mcg

Maximum1000 mcg

ToxicNo established oral toxicity

Before you take it

VeganYes

When to expect it

First Effects24-48 hours for clotting factor synthesis

Peak Benefits3-7 days for optimal clotting function

Deficiency Development1-2 weeks with inadequate intake

Toxicity OnsetRare, mainly with synthetic forms

How to measure it

$20-40

MarkerProthrombin time (PT/INR)

OptimalINR 0.8-1.2 for healthy individuals

FrequencyAs needed for bleeding disorders or anticoagulant monitoring

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 →

What actually reaches you

The label counts the carrier, your body does not

Absorption Very high 80 of 100 · best absorbed form of this compound

Delivered daily 0.1 mg

Cost per 1 mg delivered $3.17 comparative — uses the absorption score, not a measured percentage

Works better with

3 documented

+

Vitamin E

Protects vitamin K from oxidation

Antioxidant protection during storage and transport · level B

+

Calcium

Both involved in bone protein function

Complementary roles in bone matrix formation · level B

+

Vitamin D

Both contribute to bone health

D increases calcium absorption, K1 helps with bone proteins · level B

What not to take with Vitamin K1 (Phylloquinone)

2 documented

!

Vitamin A Excess

High doses may interfere with K function

Competition for similar metabolic pathways · mild significance

!

Vitamin E Excess

Very high E doses may reduce K effectiveness

May interfere with vitamin K cycle · mild significance

Medication interactions

Discuss these with a pharmacist before combining

warfarin-anticoagulants Major

Reduces anticoagulant effectiveness

What to do: Consistent K1 intake, monitor INR closely

antibiotics-broad-spectrum Moderate

May increase K1 requirements

What to do: Consider supplementation during long-term use

anticonvulsants Moderate

May increase K1 requirements

What to do: Monitor for bleeding, consider supplementation

Available forms

bioavailability compared

Ranks 3 of 4 among vitamin k forms. Vitamin K2 (MK-9) absorbs better — 85%. Compare all forms →

Phylloquinone (natural) 80

Synthetic K1 75

Phylloquinone (natural): Natural form, Well-absorbed, Safe profile

Synthetic K1: Less expensive, Stable, Widely available

Food sources

before you supplement

Kale 817 mcg/100g · 85

Spinach 483 mcg/100g · 80

Brussels sprouts 177 mcg/100g · 75

Broccoli 102 mcg/100g · 70

Too little

deficiency signs

Easy bruising and bleeding
Heavy menstrual periods
Bleeding gums
Poor wound healing
Excessive bleeding from cuts
Gastrointestinal bleeding
Intracranial bleeding (severe cases)

Too much

toxicity signs

Generally no toxicity from natural K1
Possible hemolytic anemia (synthetic forms)
Interference with anticoagulant drugs
Kernicterus in premature infants (synthetic)
No upper limit established for adults

Who benefits most

antibiotic-users

Antibiotics may reduce K1-producing gut bacteria

100-200 mcg daily during treatment

liver-disease-patients

Impaired synthesis of vitamin K-dependent proteins

Physician-determined dosing

malabsorption-disorders

Reduced fat-soluble vitamin absorption

200-500 mcg daily

newborns

Prevent vitamin K deficiency bleeding

Medical injection at birth

elderly-on-poor-diets

May have inadequate green vegetable intake

100-200 mcg daily

Where to buy it

compare forms first

Look for Vitamin K1 (Phylloquinone) at 90-120 mcg per serving. The form that matters here is Phylloquinone (natural).

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How it works

Cofactor for gamma-carboxylase enzyme
Essential for clotting factor synthesis (II, VII, IX, X)
Enables protein C and protein S anticoagulant activity
Participates in vitamin K cycle recycling
Some bone protein activation (less than K2)
Limited antioxidant activity

Key findings

what the evidence supports

Essential for blood clotting - established science since 1930s
Prevents vitamin K deficiency bleeding in newborns (ACOG 2017)
May contribute to bone health but less than K2 (Nutrients 2013)
Safe and effective for warfarin reversal (Blood 2006)

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 K1 (Phylloquinone)?

Documented effects: Blood clotting support; Wound healing; Bone health support; Cardiovascular support. Essential for synthesis of clotting factors II, VII, IX, X

How much Vitamin K1 (Phylloquinone) should you take per day?

The common daily range is 90-120 mcg. By goal — maintenance: 90-120 mcg; therapeutic: 200-500 mcg; maximum: 1000 mcg; toxic: No established oral toxicity.

When is the best time to take Vitamin K1 (Phylloquinone)?

With fat meal. First effects are typically reported within 24-48 hours for clotting factor synthesis.

What are the side effects of Vitamin K1 (Phylloquinone)?

At excessive doses: Generally no toxicity from natural K1, Possible hemolytic anemia (synthetic forms), Interference with anticoagulant drugs, Kernicterus in premature infants (synthetic), No upper limit established for adults. Safety rating at normal doses is 9 out of 10.

What should you not take with Vitamin K1 (Phylloquinone)?

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

Does Vitamin K1 (Phylloquinone) interact with medications?

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

How do you know if you need Vitamin K1 (Phylloquinone)?

The marker is Prothrombin time (PT/INR), optimal range INR 0.8-1.2 for healthy individuals. Common deficiency signs: Easy bruising and bleeding, Heavy menstrual periods, Bleeding gums, Poor wound healing.