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Can You Give Horses Human Vitamins?

Maybe you have thought, what’s the harm in giving my horse some of your multivitamins? If a vitamin is good enough for a human, it should be good enough for a horse, right?

Giving human vitamins to your horse can be dangerous. Horses need a range of minerals and vitamins, but they must be given with correct proportions. It is vital to get the right dosage according to your horse’s weight. Crushing up many human vitamins for a 500 kg horse is cumbersome, and it won’t guarantee your horse will get the correct dosage. 

The actual quantities are essential but so is the balance of the formula, so the safest way to supplement your horse’s diet is to use a correctly balanced commercial formula from a reputable manufacturer that is added to a balanced diet of Fiber, Carbohydrates, Fat, and Protein.

The dietary needs of humans and horses are different from each other.  It is not as simple as a ‘one for all solution.  Let’s look at what vitamins horses need to have a healthy life and why it’s not good to use human vitamins.

Reasons why you should not give your horse human vitamins

  • Horses are not humans, and human vitamins are not designed for equine use. It is intended for humans.  A humans’ body is anatomically different than a horse’s body.
  • A horse’s metabolisms work differently than a human’s metabolism.
  • Veterinarians have to use the licensed medication by the FDA for horses. They are legally obliged to follow that legislation. The FDA does not approve human medicine for Equine use.
  • The dosage required for horses is very different than the dosage needed for humans.
  • According to your horses’ body weight, many tablets would be needed as a horse weighs more than a human. 
  • Using human medication for horses is a dangerous risk to take; the higher the dose, the higher the chance of harmful side effects. 
  • There are many licensed Equine supplements available on the market today, and the need to use a human supplement is unnecessary. 

What are horse supplements?

Generally speaking, a supplement is given to a horse on top of his forage. Supplements are additional nutrients, minerals, vitamins, and proteins fed to horses to boost their diet or make up for a deficient diet.

Just like humans, there are several reasons why a horse might need a supplement. The horse might have a health issue, poor hoof growth, or have joint problems.  Supplements also help improve a horse’s competition performance, increase his stamina and boost energy levels.

Do horses need supplements?

People have rightly argued that horses have survived for centuries without supplements, even before the invention of supplements. Of course, this is true, but horses lived very different lives than how they live now. 

Ancient horses foraged over vast territories and had access to all kinds of grasses and seeds. These grasslands the horses grazed were rich in minerals and provided healthy nutrition. 

Modern horses do not have the luxury to graze over large open spaces looking for the best grass but are dependent on humans to provide that for them.  Consider your horse’s diet, evaluate his needs and his workload to decide if your horse needs a vitamin supplement.

What minerals do horses need?

The actual amounts are essential to know and the ratios between them. Too much of one mineral can inhibit the uptake of another.

For an average-sized horse of 500 Kg, the standards are:

MACRO  Maintenance


MICRO  Maintenance


Does Your Horse Need vitamins?

Under normal conditions, it is unnecessary to supplement vitamins unless prescribed by your veterinarian for a specific cause. There are a few exceptions for giving supplements and a few negative issues from over-supplementation.

Horses that are stabled for long periods with limited sunlight, minimal forage, and horses with chronic conditions and illness would need some vitamins to offset those abnormal situations.

Vitamin E deficiency can occur: when a horse has a low intake of pasture.  Also, when the field is of inferior quality or when horses kept stabled and are not given fresh Lucerne or Alfalfa.  Poor storage of the Lucerne will also reduce its Vitamin E content. Vitamins A and D, vitamin E, is present in grass and fresh hay, but their levels will start to decline as the hay ages.  Alfalfa hay is a better source of these vitamins than grass hay.

Vitamins are organic substances necessary for the proper nutrition of animals.  Some vitamins must be given through food, while others are produced within the body. Not all animals can make the same vitamins.  Animal feeds designed for one species are not generally suitable for another type of animal.

What vitamins do horses need?

For optimal health, horses need vitamins A, B, C, D, E, and K.  The required quantities are small but essential for optimal health.  For some vitamins, too much in the horse’s diet is just as bad as too little. Most well-known commercial horse feeds supply vitamins properly, taking the guesswork out of feeding horses.

Vitamin EVitamin E is recommended, in conjunction with selenium, primarily for horses prone to tying up.  The recommended daily dietary intake of Vitamin E for adult horses is 500-1000 IU.
Vitamins A and DThese vitamins are fat-soluble and stored by the horse.  Vit A and D rarely need to be given to a horse. Dietary excesses can be very dangerous; just ten times the requirement for Vitamin D can be toxic. The only time Vitamin D could be needed is when a horse is stabled without access to sunlight or outside.
Vitamin CHorses will synthesize sufficient for their needs. Horses in high stress may benefit from supplementing with vitamin C, but excess is harmful and should be discontinued when conditions are back to normal.
B VitaminsRiboflavin (B2), Niacin (B3), Thiamine (B1), Biotin (B7), Pyridoxine (B6), Folacin (B9), Pantothenic acid (B5), and Cobalamin B12 are all synthesized in adequate quantities within the horse’s gut.  However, periods of high stress, prolonged travel, sudden hard work, high grain intake can reduce the efficacy of the natural processes.  Therefore, a short-term supplement of B1, B2, B3, B6, and B12 will assist your horse during the stress period until his gut returns to normal.
BiotinWhen given at 15 mg per day improves quality hoof growth.
Vitamin KThe horse synthesizes vitamin K., and supplementation is unnecessary.

Vitamins and their functions in the horse’s body

Vitamin AImproves night vision, fertility and fetus development, skin and hoof care, and the immune system.
Vitamin CThe immune system and also protect the lungs from damage.
Vitamin DAbsorbing and transporting calcium through the body.
Vitamin EProtecting the horse’s body from everyday oxidative damage and developing and maintaining healthy muscles, nerves, and the immune system.
Vitamin KEssential for healthy blood and prevents blood clots.
Thiamine (B1)Metabolizes proteins, fats, and carbohydrates as well as improving a horse’s energy and power.
Riboflavin (B2)The production of energy and the immune system.
Niacin (B3)Performance and helps with digestion and healthy skin.
Pantothenic Acid (B5)Metabolism and digestion of proteins, carbohydrates, and fats.
Pyridoxine (B6)Metabolizing protein for muscle development.
Biotin (B7)Improves hoof health as well as the condition of the horse’s coat.
Folic Acid or Folate (B9)Preventing and controlling anemia by keeping red blood cells healthy.
Cobalamin (B12)Fighting tiredness and is also used by red blood cells.

Electrolytes, when does a horse need them?

A balanced correctly formulated electrolyte mix is crucial to a horse at work, particularly in conditions that cause excessive sweating.  Sweat is the most significant cause of fluid and electrolyte loss in horses.  Sweat takes with it significant amounts of water and electrolytes from the horse’s body.

Replacement of salts lost in sweat is vital to a horse’s health.  Replacing just salt (sodium chloride) is not enough, and too much salt is never good either.  A salt lick is not enough, and it has been proven that a horse can’t determine for itself how much salt it needs.  Some horses overdo the intake, and other horses will not take enough.

To support a horse on race day or competition days or during traveling and hard-working days in warm weather, use a formula like Vetpro Performance Electrolytes or Quicklyte, which is fast-absorbing and gets a rapid result.


Vitamin and mineral supplements for horses are scientifically tested and licensed for horses.  It is unnecessary and unsafe to use human vitamins for horses.  Commercial Equine supplements already contain the correct dosage and composition formulated.  Instead, invest in a product that you know is tested and safe for your horse to use. 

There are no shortcuts when it comes to your horse’s health.  Don’t risk your horse’s health by using a product on your horse that is not intended for your horse and could cause your horse harm.


Anrie Diedericks

I've been around horses since I was 6 years old and started competing at the age of 9. Horses are my greatest passion and I am thrilled to be able to share my 23 (and counting) years of experience and knowledge with you.

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