Rankings / Essentials — Vitamins & Minerals
Vitamin K1 (phylloquinone)
Essentials · Vitamin
Tier A+
Bottom line
Read Off Label grades Vitamin K1 (phylloquinone) as A+ (8.4/10) based on strong evidence, strong benefit magnitude, and a low-risk safety profile.
Confusion with K2 is the dominant clinical error — K1 supplementation does not replicate K2's arterial calcification or osteocalcin activation data.
Studied, labeled, or reported-use context: 90-120 mcg/day RDA from dark leafy greens (kale, spinach, broccoli); 5-10 mg PO or 1-10 mg IV for… — Rx (IV/IM Phytonadione); OTC; not individualized guidance.
What the evidence says
Confusion with K2 is the dominant clinical error — K1 supplementation does not replicate K2's arterial calcification or osteocalcin activation data. Newborn IM 1 mg K1 prophylaxis is standard. A consistent dietary K1 intake matters for warfarin patients more than supplementation.
Mechanism
Cofactor for gamma-glutamyl carboxylase, which activates vitamin K-dependent clotting factors (II, VII, IX, X, protein C/S) in the liver; minimal extrahepatic distribution compared with K2 menaquinones
Studied, labeled, or reported dose & route
90-120 mcg/day RDA from dark leafy greens (kale, spinach, broccoli); 5-10 mg PO or 1-10 mg IV for warfarin reversal
This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.
Citations
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Common questions
- What does the evidence show about Vitamin K1 (phylloquinone)'s effects?
- Read Off Label rates the evidence for Vitamin K1 (phylloquinone) as Strong and the benefit magnitude as strong, producing an overall grade of A+ (8.4/10). Confusion with K2 is the dominant clinical error — K1 supplementation does not replicate K2's arterial calcification or osteocalcin activation data.
- What safety findings are reported for Vitamin K1 (phylloquinone)?
- Vitamin K1 (phylloquinone) has a low risk profile in the database. Low (co-exposure with warfarin changes anticoagulation; Vitamin K1 is the antidote for warfarin overdose) Legal status: Rx (IV/IM Phytonadione); OTC (oral).
- What doses or routes are reported for Vitamin K1 (phylloquinone)?
- 90-120 mcg/day RDA from dark leafy greens (kale, spinach, broccoli); 5-10 mg PO or 1-10 mg IV for warfarin reversal This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
- How does Vitamin K1 (phylloquinone) work?
- Cofactor for gamma-glutamyl carboxylase, which activates vitamin K-dependent clotting factors (II, VII, IX, X, protein C/S) in the liver; minimal extrahepatic distribution compared with K2 menaquinones
This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.