0 Basket View Basket

Understanding Vitamin E: Why This Essential Nutrient Matters for Every Horse

Vitamin E plays a vital role in equine health, yet it’s one of the most commonly overlooked nutrients in a horse’s diet. Responsible for supporting muscle function, nerve transmission and immune resilience, vitamin E also acts as a powerful antioxidant, helping to protect cells against oxidative stress caused by exercise and metabolism.

Our partners NAF explain how Vitamin E is an essential nutrient for both humans and horses. Horses cannot manufacture vitamin E themselves, which means it has to come from their diet. While grazing on fresh pasture is an excellent source of natural vitamin E, the majority of horses now rely on preserved forages such as hay or haylage, where natural vitamin E levels degrade quickly after harvest

This can leave even well-fed horses short of this essential vitamin, with potential consequences for performance, recovery and long-term health.

The Role of Vitamin E

  • Antioxidant protection - One of the most important antioxidants, vitamin E neutralizes free radical toxins produced in every cell during metabolism, exercise and stress.
  • Muscle function - Crucial to healthy muscle function and repair, vitamin E’s role in muscle stress such as rhabdomyolysis, PSSM and MFM is well-known and increasingly recognised as vital to their management.
  • Nerve function - Low vitamin E is recognised in many nerve related condition of horses, such as EDM (Equine degenerative myeloencephalopathy) and EMND (Equine motor neurone disease).
  • Reproduction - Vitamin E supports cell wall integrity and is particularly known in both the stallion and mare for those cell walls of reproduction.
  • Immune system support - As an antioxidant and cell wall protector, vitamin E has a central role in immunity, general health and the body’s defences

Different types of Vitamin E - Natural vs Synthetic

Not all vitamin E sources are created equal. The natural form — known chemically as RRR-alpha-tocopherol — is absorbed and utilised far more efficiently than synthetic versions (which are often listed as “DL-alpha-tocopherol”).

Research shows that natural vitamin E is up to twice as bioavailable, meaning a horse absorbs and uses more of what’s provided. When choosing a supplement, check the label for the natural form to ensure your horse receives the greatest benefit.

How Much Does a Horse Need?

Requirements vary depending on diet and workload, but a general guide is:

  • Maintenance / light work: ~1,000–2,000 IU per day
  • Moderate–intense work: 2,000–5,000 IU per day
  • Horses on limited grazing or recovering from illness: may need additional support as advised by a vet or qualified nutritionist.

Owners often assume their balancer or compound feed provides enough, but these levels may not meet the demands of harder work or low-forage vitamin E intake.

Supporting Vitamin E Intake

  • Assess your forage: Hay and haylage can contain little or no active vitamin E.
  • Consider turnout: Fresh spring grass is a good natural source. 
  • Check your feed labels: Look for “natural vitamin E” (RRR-alpha-tocopherol).
  • Avoid sudden diet changes: Build up supplementation gradually and review regularly with your nutritionist or vet.

Ensuring your horse’s vitamin E status is optimised can improve muscle recovery, maintain topline, and enhance overall wellbeing — especially in horses under regular training or those managed with restricted grazing.

Vitamin E isn’t just another supplement it’s an essential component for every horse’s muscle, nerve and immune health. In today’s management systems, where preserved forage and limited turnout are common, checking that your horse receives enough natural vitamin E is a simple yet powerful step towards better performance and long-term health.