Vitamin K1, also known as phytonadione or phylloquinone, is a fat-soluble vitamin essential for several bodily functions, most notably blood clotting. It is naturally found in many green leafy vegetables and is the primary dietary form of Vitamin K. Vitamin K refers to a group of structurally similar fat-soluble vitamins, with K1 and K2 being the most common. Vitamin K1 plays a crucial role as a coenzyme for a specific class of proteins known as gla-proteins (gamma-carboxyglutamic acid proteins). These proteins are involved in various physiological processes, including hemostasis (blood clotting) and bone metabolism. The human body obtains Vitamin K1 primarily through diet, and to a lesser extent, from bacterial synthesis of Vitamin K2 in the gut. Deficiencies in Vitamin K1 can lead to impaired blood coagulation, potentially resulting in excessive bleeding. (NIH ODS, PubChem)
Deep dive
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Known interactions
Category rule: vitamin × medication
Note
Certain vitamins interact with specific medications (e.g., vitamin K with blood thinners).
Specific pairs are checked against a licensed source; confirm with your provider.
Compound-pair rule
Caution
Vitamin K reverses vitamin K antagonist activity and shifts INR.
Keep vitamin K intake consistent; do not start or stop supplementation without INR monitoring.
Compound-pair rule
Caution
Vitamin K reverses vitamin K antagonist activity and shifts INR.
Keep vitamin K intake consistent; do not start or stop supplementation without INR monitoring.
Compound-pair rule
Caution
Vitamin K reverses vitamin K antagonist activity and shifts INR.
Keep vitamin K intake consistent; do not start or stop supplementation without INR monitoring.
Compound-pair rule
Caution
Vitamin K reverses vitamin K antagonist activity and shifts INR.
Keep vitamin K intake consistent; do not start or stop supplementation without INR monitoring.
Compound-pair rule
Caution
Vitamin K reverses vitamin K antagonist activity and shifts INR.
Keep vitamin K intake consistent; do not start or stop supplementation without INR monitoring.
Compound-pair rule
Caution
Vitamin K reverses vitamin K antagonist activity and shifts INR.
Keep vitamin K intake consistent; do not start or stop supplementation without INR monitoring.
Frequently asked
Sources referenced
["National Institutes of Health (NIH) Office of Dietary Supplements (ODS)","MedlinePlus (National Library of Medicine)","PubChem (National Library of Medicine)","DrugBank Online","Examine.com","Food and Drug Administration (FDA) drug labels","Cochrane Library (review findings)"]
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician.
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