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Vitamin K1 (Phytonadione) — SacredBod supplement bottle (illustrative)
Supplement · Vitamin

Vitamin K1 (Phytonadione)

100 mcg · vegan · gluten-free · 90 caps

Easy bruisingPoor clottingVascular calcificationLow vitamin K statusOsteoporosis riskLow vegetable intake BloodBonesBlood vesselsHeart valves
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Overview Stacks Timing Related Research FAQs

What it is

Vitamin K1 (phylloquinone or phytonadione) is the primary dietary form of vitamin K, found in leafy green vegetables, plant oils and herbs. It is a fat-soluble vitamin essential as a cofactor for the enzyme gamma-glutamyl carboxylase, which activates vitamin K-dependent proteins (VKDPs) including clotting factors II, VII, IX and X, as well as matrix Gla protein (MGP) and osteocalcin. Unlike vitamin K2, K1 is primarily known for its coagulation role, though emerging evidence supports cardiovascular benefits.

How it works

As a cofactor for gamma-glutamyl carboxylase, K1 carboxylates glutamate residues on VKDPs, converting them to active forms. In coagulation, this produces functional clotting factors. In vascular tissue, K1 activates MGP, which inhibits calcium deposition in arteries and valves. A 3-year RCT found that 500 mcg/day K1 slowed coronary artery calcification progression by 6% in older adults with preexisting calcification. Higher dietary K1 intake (~120 mcg/day) is associated with lower carotid intima-media thickness and reduced cardiovascular events in older women.

Who should take it

Individuals seeking foundational vitamin K support for coagulation and bone health, those with low vegetable intake wanting K1 insurance, people interested in vascular calcification prevention, and those on vitamin D/calcium supplementation wanting to ensure proper calcium direction. Not a replacement for anticoagulant therapy management.

Avoid / careful

Individuals taking warfarin or vitamin K antagonists without medical supervision (K1 directly antagonises warfarin). Those with thrombophilia or hypercoagulable disorders. Not for people on therapeutic anticoagulation unless directed by their physician. Side effects: Generally well-tolerated at 100–500 mcg/day. Very high doses may interfere with warfarin anticoagulation. Rare allergic reactions to injectable forms. No toxicity from oral doses within recommended ranges.

When to take it

Morning
Noon
Evening
Night

How to take it

With food
Empty stomach
Before food

FAQs

Frequently asked

How long before I see results?
Coagulation effects are immediate — K1 is essential for daily clotting factor synthesis. Vascular calcification benefits require 3–6 months based on RCT data. The PASSPORT trial is testing 16-month outcomes for aortic stenosis.
Can I take it with warfarin?
No — unless specifically directed by your physician. Warfarin is a vitamin K antagonist; supplemental K1 will reduce its anticoagulant effect and may cause thrombosis. Patients on warfarin require consistent (not increased) vitamin K intake.
Is K1 or K2 better for heart health?
Both activate MGP, but evidence is stronger for K2 MK-7 in cardiovascular calcification. K1 has shorter half-life and is less efficiently converted to K2 in tissues. For cardiovascular focus, K2 MK-7 is preferred; K1 provides foundational coagulation and general VKDP support.

In plain English

A plain-English read of the literature behind this supplement. Not a clinical recommendation.

Key citations: PMID 2682995 (3-year RCT: K1 slowed CAC progression by 6%), PMID 12049302 (higher K1 intake associated with lower ASVD events and mortality), PMID 12715181 (PASSPORT trial design — 10 mg K1 for aortic stenosis), PMID 16505257 (meta-analysis of warfarin reversal with vitamin K)

Editorial notes

SacredBod's longer take on Vitamin K1 (Phytonadione) — context the structured blocks above don't capture.

What It Is

Vitamin K1 (phylloquinone or phytonadione) is the primary dietary form of vitamin K, found in leafy green vegetables, plant oils and herbs. It is a fat-soluble vitamin essential as a cofactor for the enzyme gamma-glutamyl carboxylase, which activates vitamin K-dependent proteins (VKDPs) including clotting factors II, VII, IX and X, as well as matrix Gla protein (MGP) and osteocalcin. Unlike vitamin K2, K1 is primarily known for its coagulation role, though emerging evidence supports cardiovascular benefits.

How It Works

As a cofactor for gamma-glutamyl carboxylase, K1 carboxylates glutamate residues on VKDPs, converting them to active forms. In coagulation, this produces functional clotting factors. In vascular tissue, K1 activates MGP, which inhibits calcium deposition in arteries and valves. A 3-year RCT found that 500 mcg/day K1 slowed coronary artery calcification progression by 6% in older adults with preexisting calcification. Higher dietary K1 intake (~120 mcg/day) is associated with lower carotid intima-media thickness and reduced cardiovascular events in older women.

Who Should Consider It

Individuals seeking foundational vitamin K support for coagulation and bone health, those with low vegetable intake wanting K1 insurance, people interested in vascular calcification prevention, and those on vitamin D/calcium supplementation wanting to ensure proper calcium direction. Not a replacement for anticoagulant therapy management.

Dosage Guide

Typical dose: 100 mcg per day

Form: capsules (90 count)

Best time: morning

With food: with-food

Expected onset: Immediate for coagulation; 4–8 weeks for vascular calcification markers

Cycling: No cycling required. Essential vitamin for continuous daily intake.

Safety & Side Effects

Known side effects: Generally well-tolerated at 100–500 mcg/day. Very high doses may interfere with warfarin anticoagulation. Rare allergic reactions to injectable forms. No toxicity from oral doses within recommended ranges.

Who should avoid: Individuals taking warfarin or vitamin K antagonists without medical supervision (K1 directly antagonises warfarin). Those with thrombophilia or hypercoagulable disorders. Not for people on therapeutic anticoagulation unless directed by their physician.

Avoid combining with: Warfarin and vitamin K antagonists, Anticoagulant medications, High-dose vitamin E (theoretical antagonism of vitamin K), Antibiotics (may reduce gut K2 synthesis, increasing K1 demand)

India-Specific Context

Vitamin K1 (Phytonadione) is available on Amazon India with varying brand quality. When selecting a product, verify standardization claims against the evidence base cited above. Indian brand preferences include Carbamide Forte, HealthyHey, Nutrabay Pure, Pure Nutrition, Now Foods, Nutricost, Himalaya, Patanjali, Dabur, Trexgenics, Evorina, Nervana, Life Extension, VITARUHE, ASTERVEDA, BECLEC, and GreenOpia. Prices vary significantly; compare cost-per-active-dose rather than capsule count alone.

Schedule status in India: Not a Schedule H drug; available as dietary supplement/herbal product.

Research Summary

Key citations: PMID 2682995 (3-year RCT: K1 slowed CAC progression by 6%), PMID 12049302 (higher K1 intake associated with lower ASVD events and mortality), PMID 12715181 (PASSPORT trial design — 10 mg K1 for aortic stenosis), PMID 16505257 (meta-analysis of warfarin reversal with vitamin K)

Evidence grade: B — Multiple RCTs for CAC progression; large observational studies for cardiovascular outcomes

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