Can You Take Menadione (Vitamin K3) and Vitamin E Together?

Dose or timing may matter

The short answer

High-dose vitamin E antagonizes vitamin K function by inhibiting vitamin K-dependent carboxylase. Menadione (vitamin K3) is a synthetic provitamin K with weaker biological activity than K1 or K2, making it more susceptible to vitamin E antagonism.

How to arrange timing

Avoid high-dose vitamin E (>400 IU/day) when relying on menadione for vitamin K activity.

Reference

Reference noted for this combination: Booth SL et al. Effect of vitamin E supplementation on vitamin K status in adults with normal coagulation status. Am J Clin Nutr. 2004;80(1):143-148

Important context

Whether supplements suit you together also depends on dose, product formulation, health conditions, and medication use. Ask a doctor or pharmacist first if you take medication, are pregnant or breastfeeding, or have a chronic condition.