Vitamin E for horses


Managing equine nutrition can be daunting, as each horse has unique calorie and nutrient requirements. I will never stop recommending an equine nutritionist to create a well-balanced diet for your horse. It’s an investment in your horse’s health. Nutrition for horses is complicated! One essential nutrient that should not be overlooked is vitamin E. Luckily for our horses, there is ample research and understanding available to ensure that every horse receives adequate levels of this necessary nutrient.


Table of contents


What is vitamin E?

Your horse’s neuromuscular system

Selenium’s role in the horse’s body

Providing vitamin E to horses 

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horse grain bucket with hay and apple

You can supplement your horse if needed


What is vitamin E?


  • Vitamin E is a potent antioxidant that helps protect cells from damage caused by free radicals. These free radicals are created via oxidative stress within cells as the body uses fats and carbs. Free radicals have an odd number of electrons; hence they are unstable. Fixing this instability requires free radicals to steal electrons, contributing to cell damage and death. Vitamin E fights this process.   


  • Exercise and aging take a toll on the body. There’s an increase in energy use, creating a more significant need for antioxidants. When free radicals outnumber antioxidants, your horse may have sore muscles, stiff joints, and tissue damage.


  • While there are many antioxidants, such as carotenoids, amino acids, and vitamin C, vitamin E is unusual. There is no specific body function that needs this essential nutrient. Vitamin E likes to help with many body systems: muscular, circulatory, immune, nervous, and reproductive. 


  • Vitamin E deficiency opens the door for health problems, including muscle weakness, poor immunity, and even neurological problems.


lush green pasture with barn in the background

Pasture grass is the best source of natural vitamin E


Your horse’s neuromuscular system


  • General poor performance and muscle soreness can be related to vitamin E deficiency. Additionally, three neurological disorders are directly linked to vitamin E deficiency.

Equine neuroaxonal dystrophy (eNAD)


  • Equine neuroaxonal dystrophy affects young horses and has a genetic component. With long-term vitamin E deficiency, a horse may become uncoordinated, clumsy, and even suffer extreme debilitation. One working theory is that vitamin E protects the brain and spinal cord neurons while a horse grows. 


Equine motor neuron disease (EMND)


  • Older horses deficient for extended periods, usually 18 months or more, experience nerve malfunctions. This creates weight loss and weakness. A horse with EMND may lie down more than usual, hang their heads low, and have an awkward stance. There is the possibility for recovery. 

Vitamin E deficient myopathy


  • Horses with short-term deficiencies may show twitching and muscle weakness. There are no obvious and direct neurological changes; adding this essential nutrient to the diet usually leads to recovery.



  • In other cases, horses with neurological disorders like equine protozoal myeloencephalitis (EPM) and wobbler’s syndrome may benefit from additional vitamins, including E, in their diets. It’s worth having your horse’s bloodwork checked for serum levels of vitamin E. If the levels are reasonable, there’s no reason to add more.  


vet holding a horse tail for neurological exam

Any sign of neurological disorder warrants a full exam from your vet


Selenium’s role in the horse’s body


  • Selenium is a mineral that plays a vital role in the horse’s body, regulating thyroid hormone activation and acting as an antioxidant. A selenium deficiency may lead to muscle degeneration and may cause some types of tying up in horses.  


  • Selenium is found in soils and will affect the selenium in a horse’s forage supply. Where your horse’s hay is grown will impact how much selenium they receive, and you may need to supplement. 


  • Here’s the deal with selenium – it works alongside vitamin E. The two antioxidants may compensate for each other if there is a shortage. Selenium is also a nutrient you don’t want to overfeed – too much of a good thing can cause problems.  


hors supplements being put into tub


Providing vitamin E to horses 


  • As horses produce only small amounts of vitamin E, it must be obtained through their diet. For this reason, it is critical that horse owners provide their horses with a balanced diet that includes sufficient levels of vitamin E. 


  • Your horse’s needs may vary depending on the season and the availability of fresh pasture. And while it’s readily available to horses as pasture, vitamin E disappears a week after being cut for hay. 


  • It’s worth noting that some forms of vitamin E are more beneficial to horses than others. The natural form of vitamin E, d-alpha-tocopherol, is more easily absorbed and utilized by horses than the synthetic form, dl-alpha-tocopherol. Therefore, horse owners should strive to provide their horses with natural sources of vitamin E whenever possible. 


  • Research tells us that tocopherols in the wilds of nature are 36% more biologically active than the synthetic version. 


several bags of horse feed

Read the labels and look for d-alpha-tocopherol – the natural variation


  • You can find vitamin E in a few sources – a stand-alone supplement, as part of a bagged feed or ration balancer, or out in nature’s salad – the pasture. For supplements and feeds, you may not know which version of vitamin E you are feeding. Some brands, however, will specify which version is included.


  • Feeding supplements is easy by top-dressing or mixing with bagged feeds or adding to hay piles. Ideally, you can split dosages into several offerings in a day. For lactating or pregnant mares, young horses, or horses in extreme training, their needs may be greater. 


 A quick reminder that equine nutritionists earn PhD’s about these very topics and are affordable!



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For fun time reading, here are some resources: 


Traber, M.G. 1999. Vitamin E. In: M.E. Shils, J.A. Olson, M. Shike, and A.C. Ross (Eds). Modern Nutrition in Health and Disease (9th Ed.). p. 347. Williams & Wilkins, Baltimore.


“Vitamin E: An Essential Nutrient for Horses: KPP,”

Kentucky Performance Products, 22-Aug-2018. [Online]. Available:


H. S. Thomas, “Why your horse needs vitamin E,” The

Horse Owner’s Resource, 07-Nov-2017. [Online]. Available: 


The College of Veterinary Medicine at Michigan State

University. 2021. Neuromuscular Diseases related to vitamin E. [online] Available at:



King, M., 2021. Studies on Vitamin E – The Horse.

[online] The Horse. Available at:



 Ramey, D., 2021. Vitamin E: Necessary to horses, but

there’s a lot to learn. [online] Veterinary Practice News. Available at:



 Kentucky Equine Research. 2021. Selenium for Horses:

How Important Is It? – Kentucky Equine Research. [online] Available at:



H. S. Thomas, “Why your horse needs vitamin E,” The

Horse Owner’s Resource, 07-Nov-2017. [Online]. Available: 


Ramey, D., 2021. Vitamin E: Necessary to horses, but

there’s a lot to learn. [online] Veterinary Practice News. Available at: