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Horse Supplements: Do Horses Need Them? Which Are the Best?

Last updated: March 11, 2024

By: Miles HenryFact Checked

My granddaughter noticed that I was top-dressing my horse’s feed with Healthy Coat, a mineral supplement. She wanted to try it out on hers, but I explained that her horse was doing fine and that horse supplements aren’t always needed.

Some horses need supplements because they have a vitamin deficiency or they aren’t getting the necessary nutrients from their food. In these cases, supplements can help a horse stay healthy by adding the extra vitamins and nutrients it needs.

Horse owners often give their horses supplements that they don’t need. Most horses get all they need to stay healthy by simply providing them quality hay (or grass), access to fresh water, and ensuring they get plenty of exercise.

Picture of a thoroughbred stallion.

Horses. We love them. We more than love them. They nourish us –  the way they neigh when they hear us coming, the warmth of their breath, the countless times they make us laugh.

And that is precisely why you’re here. You love your horse, and you care about its well-being. The best way to show our love and respect for these majestic animals is by learning to care for them properly and knowing what nutrients they need to stay healthy.

Are Supplements Necessary for Horses?

One of the more important aspects to take note of when working with horses is their diet. I find that many horse owners don’t realize they are feeding an animal, not a machine!

Horses need minerals and vitamins just as much as humans do – in fact, some horses may require them even more than others based on their activity level and genetics.

One thing you can do is to provide your horse with a steady supply of hay or grass all day long. And since not all horses are the same sometimes, we need to fill nutritional gaps with supplements.

But not all horses need supplements. There have been reports of horse owners injecting mineral supplements into their horses, causing serious harm and even killing them. In addition, some horse owners get inject their horses with Ace they get from friends.

You should not use injectable supplements without discussing them with a vet first. Your vet is the best person to guide you in this regard. To determine if your horse needs a supplement, consider its feed and the individual horse’s nutritional requirements.

Generally, a horse’s supplement and feed requirements depend on its age and activity. Older horses may need extra supplements to keep them healthy since their digestive system isn’t as efficient anymore. A broodmare may need supplements to help her deal with the added stress of pregnancy and lactation.

Remember: no two horses are the same. The number of supplements or feed additives that keep one horse fit and healthy could be too much for another horse.

Every horse has different nutritional requirements, even if it does the exact amount of work as another horse. In fact, there is an estimated 20-30% difference in horses’ energy needs.

Take the example of endurance horses. Some stay fit and healthy on pasture and grass alone; others might need nearly 6-12% grain and supplements added to their grass and hay to maintain the same fitness levels.

Picture of healthy coat supplements.

What nutrients do horses need?

All horses need a balanced daily ratio consisting of six things: water, carbohydrates, proteins, fats, vitamins, and minerals. It is important for horses to get the right amount of nutrients.

If they are not getting enough, it could lead to serious health problems. The supplement we use the most often is Red Cell.

It is a vitamin-iron-mineral supplement designed to provide vitamins and minerals that may be lacking or insufficient in a horse’s regular diet. We’ve been using it for years and haven’t found another that is as reliable.

Protein and carbohydrates

Horses have a unique ability to convert grass and hay into protein to build their large muscles. But to do this, they have to eat a lot. Even at a light level of work, horses should eat about 1.5 to 2 % of their body weight in forage.

Thus, a 1000 lb. horse will need to eat 20 lb. of forage per day. These 20 lbs. can come from different sources like hay, grass, legume, or fodder. If your horse is in training, it typically needs to eat more calories and increase its protein intake; one way you could do this would be with a supplement.


Horses get very little fat from their diets. So speak to your veterinarian about supplementing with flaxseed oil, vegetable oil, or other sources of omega-essential fatty acids. Older horses seem to need fat supplements more than younger horses.

 You can generally feed ½ a cup of flaxseed per 400 lbs. of body weight per day. If you opt for a commercial supplement, choose one that contains calcium to correct the inverted calcium-to-phosphorus ratio found in flaxseeds.

Vitamins and minerals

Horses also need vitamins and minerals, and deficiencies in these can lead to several health issues ranging from colic to lameness.  A daily dose of an equine multivitamin can help prevent these issues. Your vet will tell you about a horse’s individual vitamin needs.

You can also provide your horse with a mineral block or give it a mineral supplement based on its diet. For example, if your horse is on a grass-hay-only diet, its mineral and vitamin needs will differ from that of a horse getting both legumes and grass.

Here are some vitamins your horse might need if it is on a grass-hay-only diet.

  • Vitamin E – A horse needs 1 IU of vitamin E per pound of body weight. For an 1100 lb. horse, that translates to 1100 IU of vitamin E.
  • Beta carotene – Add a daily dose of 72 mg of beta carotene per kg of body weight or 30 IU of Vitamin A. Do not feed this to horses on alfalfa diets.
  • Biotin – This helps keep hooves and tail, and mane strong. It also promotes shiny coats.
  • Vitamins B and C – Horses generally do not need these separately unless they are ill or anemic.
  • Vitamin D – In excess, it can cause bruise calcification. So speak to your vet before supplementing.

Psyllium supplement

If your horse grazes in a pasture, it might end up eating dirt and sand along with grass. This isn’t bad because it could help their teeth and give them needed iron. However, the sand can build up in the animal’s intestine over time, causing colic.

To reduce the amount of sand buildup in your horse’s hindgut, feed it a psyllium supplement once a week or daily for several consecutive days, at least once a month. This can improve digestion and intestinal motility.

Pre and Probiotic supplements

These supplements maintain your horse’s digestive health and also boost its immunity. They also heal the horse’s gut, add beneficial micro-flora, and help the horse get the most out of its feed.

Types of supplements for horses

The most common types of supplements for horses are:

  • Dietary horse supplements: Dietary supplements provide vitamins and minerals your horse needs to maintain their health.
  • Digestive supplements: These supplements can contain probiotics, yeast cultures, and prebiotics, which help the bacteria in horses’ hindguts work better and improve digestion.
  • Calming horse supplements: Calming supplements can alleviate anxiety and tension. They are especially helpful for horses that get nervous during transport.
  • Joint supplements: These supplements may provide relief by decreasing inflammation associated with degenerative joint conditions like arthritis, enabling them to continue an active lifestyle without pain.
  • Hoof & Coat supplements: Provide minerals and vitamins for hoof conditioning and support healthy skin and shiny coats.
  • Weight gain supplements: Some horses have trouble maintaining weight and muscle and need a weight gain supplement. There are many different types on the market that can help, and these typically contain high amounts of fat, amino acids, vitamins, minerals, and other nutrients.

Note: You should only give your horse joint supplements after consulting with your vet. Some owners preemptively feed their horses equine joint supplements containing hyaluronic acid, yucca, chondroitin, and glucosamine to prevent degenerative joint disease and arthritis. I discussed this in detail in an article about joint supplements’ benefits and drawbacks.

Registered supplements vs. unregistered horse supplements

The market for horse supplements is huge. You can find a supplement to fix just about any problem your horse has, but be careful because many of them are worthless and won’t work.

If a product claims to prevent or treat an ailment,- it is subject to strict regulations and has to go through a registration process with the Agricultural and Veterinary Medicines Authority before being sold in stores.

Once registered, they will have a label that includes full disclosure of active ingredients, quantities, and often the mode of action. so potential buyers can make informed decisions about what their animal needs. You should only buy horse supplements that are registered!

Below is a YouTube video that addresses what supplements all horses should have.

YouTube video

The Best Vitamin Supplements for Horses

Horse supplements can help with a variety of issues, such as joint pain relief and calming nerves. Here are some favorite products: for full disclosure, I haven’t tried the calming supplement yet, but it was highly recommended to me by a couple of horse trainers.

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Top choices for supplements

1.      Best Overall: Horse Guard Equine Vitamin/Mineral Supplement


  • It contains biotin, 1500 IU of vitamin E, zinc, pre and probiotics, and essential trace minerals, minerals, and vitamins missing in hay.
  • Uses high-quality pharmaceutical-grade ingredients.


  • Formulated by certified equine nutritionists – so you don’t need to guess how much to feed. Feed just 2 oz. per day per 1000 lb. body weight
  • Promotes strong hooves and shiny coats.
  • Great flavor, which horses love.


  • Great product but a small bag.

2.      Best Budget: Farnam Vita Balanced Vitamin/Mineral Supplement


  • It contains proteins, vitamins, and essential bio-available minerals to support health and performance. It also contains antioxidants – vitamins E and selenium.
  • For horses of all ages and disciplines.
  • Easy-to-feed pellet form


  • Unlike other supplements, most horses loved it and did not leave any behind in their feed bucket.
  • Encourages horses to drink more water too.


  • A few picky eaters did not like its taste.

3.      Best NASC Certified: Manna Pro SHO-GLO Supplement

NASC is National Animal Supplement Council. This non-profit organization regulates and monitors animal feed and supplements to ensure their well-being.


  • Manna Pro supplement is specially formulated for show horses. It promotes shiny and healthy coats.
  • This NASC-certified supplement contains balanced vitamins, minerals, and yeast. This optimizes the animal’s digestive health.
  • Many vets and horse breeders recommend this supplement for show and performance horses.
  • Its anti-oxidant content boosts immunity.


  • Easy to feed pellets
  • Healed cracked hooves.


  • Did not improve coat condition in a small percentage of horses.

Can you give a horse too many supplements?

Do you ever wonder if your horse can get too much of a good thing? When it comes to supplements, you can feed them too many and too much.

It is possible to overfeed horses with supplements. When you feed your horse too many supplements, it can cause harm to its digestive system and even lead to death in some cases.

If you think your horse needs more than the recommended amount of supplements, please consult with a professional before feeding, increasing what’s recommended!

Horses that eat a balanced diet will need minimal quantities of supplements. Some horses may not need supplements at all, depending on their diet, age, and activity.

It is possible for a horse owner to accidentally over-feed a horse fat-soluble vitamins like A, E, D, and K. These are stored in the horse’s tissues and, in excess, they can be very dangerous.

For example, too much vitamin D could cause bruises to calcify. Likewise, in excess, vitamin A could cause bone deterioration.

If your horse is eating green alfalfa, it does not need extra Vitamin A because green alfalfa already contains almost 70 times the vitamin A that most horses need.

A lactating mare needs about 27500 IU of vitamin A while a non-reproductive horse needs only 12500 IU of vitamin A. That is why it is essential to check with a veterinarian expert before feeding horse supplements.

Key Takeaways – Horse Supplements

Horses may or may not need vitamin and mineral supplements depending on their diet, activity, overall health, and age. If a horse’s diet does not provide all the necessary vitamins and minerals, you should consider supplements but only after speaking to a vet first.

Horses need antioxidant vitamins like vitamins A, E, and K. They may also need Vitamin C and D as well as biotin to maintain hoof health. A horse also needs balanced minerals like iron, calcium, phosphorus, selenium, and other trace minerals.


Can you give horses human vitamins?

No. Just like humans cannot and should not take horse supplements, you mustn’t feed your horse-human vitamins. Both have different anatomical structures, metabolisms, and nutritional needs. Some human vitamins can be downright damaging or toxic for a horse.

How much biotin do horses need?

Horses need about 20 mg of biotin per 1100 lb. You need to feed biotin supplements for nearly six months to see results in the coat, mane, and hooves.