A Pet Food Ingredient to be Wary of: Menadione Sodium Bisulfate


While it’s a little noticed pet food ingredient, Menadione Sodium Bisulfate (and it’s many named variations) is one ingredient to look out for and avoid.  This ingredient is commonly found in many dog foods, cat foods, and treats.  Unfortunately, it doesn’t have the best reputation for being a safe or useful pet food ingredient.  Since there are alternatives for pet food makers to use, it makes you wonder why some put our pets at risk.

Menadione Sodium Bisulfate is a synthetic version of vitamin K.  You’ll see it within the fine print of many pet foods ingredient list.  In addition, of course, it’s not as simple to find it as it should be.  Some pet food ingredient lists will say ‘menadione’, and some will mention vitamin K3 in parenthesis – and these are just a few of the possible variations you have to look for.


This ingredient is added to pet foods and treats as an inexpensive source of vitamin K.  In people – deficiencies of vitamin K can lead to blood clotting particularly in the stomach and can lead to intestinal complications.  An example for pets, veterinarians will administer an injection of K1 (not the synthetic K3) to a pet who has consumed a rat poison which causes internal bleeding.  Food sources of natural vitamin K (K1) are green leafy vegetables; which are not on the ‘top ten’ list of many pets.  Pet food ingredients that could provide natural sources of vitamin K are alfalfa and kelp.  However, as you probably have figured out, synthetic vitamin K or menadione is a great deal less expensive than the natural sources of alfalfa and kelp.


Knowing that a pet food company would opt for a synthetic ingredient in contrast to a natural ingredient is bad enough, but it takes one step further on the ‘bad scale’ with Menadione Sodium Bisulfate.  This ingredient can be highly toxic in high doses.  Hazard information regarding menadione lists “carcinogenic effects” and states “the substance is toxic to kidneys, lungs, liver, mucous membranes.  Repeated or prolonged exposure to the substance can produce target organs damage.”  http://www.sciencelab.com/xMSDS-Menadione sodium bisulfite-9924604

More information on menadione sodium bisulfate and pets can be read at http://www.dogfoodproject.com/index.php?page=menadione.


With the science based information available on this ingredient, there is no sound reason for menadione to be considered as a pet food or pet treat ingredient; that is other than a big money saver for a pet food company.  AAFCO and the FDA have no restrictions to the use of menadione in pet foods, and the pet food can even proudly claim ‘Natural’ on the label even if it contains this un-natural ingredient.  Look at the fine print of your pet’s food and treats for menadione; sources of natural vitamin K (alfalfa and kelp) seem to be a far better option.