Is Vitamin A Safe with Vitamin K2?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Maintain preformed Vitamin A intake within recommended limits (below 1,500 mcg RAE/day) when using Vitamin K2 for bone health. Excessive Vitamin A may undermine the bone-protective benefits of Vitamin K2.
Why this interaction occurs
High-dose preformed Vitamin A has been shown to impair osteocalcin carboxylation, the primary mechanism by which Vitamin K2 (as MK-7 or MK-4) promotes bone mineralization. Animal and observational human data suggest excessive retinol blunts the gamma-carboxylation of osteocalcin needed to bind calcium into bone matrix.
Evidence
Evidence level: limited.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 661,083 reports mentioning Vitamin K2. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Vitamin K2 + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All Vitamin A interactions → · All Vitamin K2 interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.