Last updated: October 8, 2026
Walk down the supplement aisle at any feed store, and you’d think every horse needs a scoop of something. There are tubs for hooves, joints, coats, guts, and nerves, and most of them aren’t cheap. So what supplements do horses need, and which ones are just making expensive manure?
Here’s how to check what your horse’s diet is missing, which supplements may help, and which claims deserve a closer look.
Table of Contents
What Supplements Do Horses Need?
A healthy horse on a balanced ration may not need anything beyond salt. The catch is that good-looking hay and a small scoop of feed don’t necessarily make a balanced ration. Many forages come up short on some vitamins and trace minerals, and a fortified feed only covers those gaps when it’s fed at the amount on the bag. Rutgers Cooperative Extension’s fact sheet Does My Horse Need Supplements? starts from the same place: look at the hay, the feed, and the horse before you buy anything.
For most horses, the supplements that matter are the simple ones:
- Salt: Every horse needs it every day, so keep a salt block or loose salt available.
- A ration balancer or vitamin-mineral supplement: For horses that live mostly on hay or pasture and get little or no fortified feed.
- Vitamin E: Fresh green forage is a rich source, but levels drop as hay is stored. Horses with little or no fresh grazing may need extra, depending on the rest of the diet.
- Electrolytes: Sweat carries sodium, chloride, and potassium out of the body, so horses that sweat heavily in hard work or heat may need them replaced.
A ration balancer is a concentrated feed that supplies vitamins and minerals, and often some protein, in a small daily serving. It isn’t the same as feeding a handful of regular grain. If you’re not sure what your horse’s ration covers, start with the vitamins and minerals horses need and compare that with what’s on your feed tag.
Hay is usually the biggest part of the diet, so choosing good hay and knowing how much your horse eats come before any tub on the shelf.
Which Horses May Need a Supplement?
Use this table to match your horse’s setup before you talk it over with your vet or an equine nutritionist:
| Situation | What may help | Keep in mind |
|---|---|---|
| Mostly hay or pasture, little or no fortified feed | Ration balancer or vitamin-mineral supplement | Choose one that complements your forage and feed it at its recommended rate |
| Little or no fresh grazing | Vitamin E | Ask your vet whether testing makes sense |
| Heavy sweating in hard work or heat | Electrolytes | Always offer plain water, too |
| Growing horses and broodmares | A feed or balancer formulated for their stage of life | Their needs differ from a mature riding horse |
| Trouble chewing hay or holding weight | A suitable senior feed or forage replacement | This is a feeding change first, so have the teeth and weight loss checked |
| Poor hoof quality | Check the ration and hoof care first | A biotin supplement may be worth trying if the problem continues |
| Diagnosed deficiency or medical condition | Whatever your vet recommends | Follow the vet’s dose and plan |
Older horses often need a different feed before they need a supplement, and feeding old horses starts with their teeth and body condition. Horses in hard training have higher energy and electrolyte needs, which ties into feeding performance horses. For a horse with equine metabolic syndrome, the diet itself matters far more than any add-on.
Types of Horse Supplements
Some supplements fill a known nutritional gap. Others are sold for results such as stronger hooves, better joint comfort, or a calmer horse. Those uses can overlap, so ask two questions: does your horse need what’s in the product, and is there evidence it will help?
These are the main categories you’ll see on the shelf. Being sold for a problem doesn’t mean a product has been shown to solve it.
| Type | Common ingredients | Commonly marketed for |
|---|---|---|
| Vitamin and mineral | Vitamins A and E, selenium, zinc, copper | Filling gaps in forage-based diets |
| Electrolytes | Sodium, chloride, potassium | Replacing what’s lost in sweat |
| Hoof | Biotin, methionine, zinc | Hoof quality and growth |
| Joint | Glucosamine, chondroitin, MSM, hyaluronic acid | Joint comfort and mobility |
| Digestive | Probiotics, prebiotics, yeast | Gut health |
| Weight and coat | Omega-3 fats, flaxseed, rice bran | Weight gain and coat shine |
| Calming | Magnesium, herbs, amino acids | Nervous or reactive horses |
If your horse sweats heavily, keep plenty of plain water available and watch for signs of dehydration. Before buying a digestive supplement, review the forage and feeding routine. Understanding how a horse digests feed helps explain why those basics matter.
Do Horse Supplements Really Work?
Some do, and some don’t. A supplement category can be useful without every product in it being useful. It helps to think about them in three groups:
- Clear nutritional purpose: Salt, vitamins and minerals where the diet falls short, electrolytes when heavy sweating increases losses, and specific nutrients for a deficiency your vet has identified. If the horse is short on a nutrient, supplying it helps.
- Mixed or product-dependent evidence: Joint supplements, probiotics, calming products, and many herbal blends. Some horses may benefit, but results vary by product and by horse.
- Marketing ahead of the evidence: Products that promise a lot for a problem that isn’t nutritional in the first place.
Hoof supplements sit somewhere in the middle. Biotin can help some horses with weak hooves, but Kentucky Equine Research notes that biotin takes at least 6 to 9 months to show results, since it only affects new hoof growth. Poor hooves aren’t automatically a biotin deficiency, either, and hoof nutrition involves more than one nutrient.
For joint supplements, the research deserves a closer look. Mississippi State University Extension’s review of equine joint supplementation found research on oral joint supplements in horses has been inconclusive and advises owners to proceed with caution. Whether joint supplements are worth the money depends on the horse and the product, so look for research on the actual formula, not just one ingredient in it.
Keep in mind that supplements don’t have to prove they work before they’re sold. The University of Florida’s overview of equine supplements makes that point and warns that safety and effectiveness in people don’t guarantee the same in horses. A label tells you what a product claims to contain, not whether it’ll help your horse.
How to Choose a Supplement for Your Horse
The best supplement for your horse is the one that solves a problem your horse has. Before you buy one, ask yourself these questions:
- What problem am I trying to solve? If you can’t answer that, don’t buy it yet.
- What’s my horse already getting? Add up the hay, pasture, feed, balancer, salt, and anything else in the feed room. A hay test helps if you’re feeding mostly hay.
- Is the problem nutritional? Weight loss, a dull coat, bad hooves, stiffness, or a nervous horse can have causes no supplement will fix, so get your vet’s opinion first.
- Is there evidence the ingredient helps? Look past testimonials to the ingredient, the amount per serving, and any research on the product.
- Am I doubling up? Check whether another product already supplies the same nutrients.
Quality controls matter, too. The NASC Quality Seal means the company passed an independent quality audit and takes part in ongoing compliance requirements, including random independent product testing. It gives you more confidence in how a product is made and labeled, but it doesn’t tell you whether it’ll work for your horse.
If your horse competes, check the current rules of your racing commission or governing organization before you feed any supplement, especially herbal or calming products. The University of Florida overview notes that some common herbs are prohibited in competition. Don’t assume a product is allowed just because it’s sold over the counter, and ask your vet about it if you’re not sure.
Once you start a supplement, agree with your vet on what improvement to look for and how long to give it. Some benefits show up in a few weeks, some take months, and a needed vitamin or mineral doesn’t always show a visible change at all.
Can You Give a Horse Too Many Supplements?
Yes. Several products can supply the same nutrients, and none of them may look excessive on its own. A hoof supplement may contain zinc and copper. Your ration balancer already supplies both, and then a coat or joint product adds another dose. What matters is the total your horse eats each day.
Selenium is a good example of why that matters. Horses need it, but too much can be toxic. Before adding a selenium supplement, have your vet or an equine nutritionist check what the full ration already supplies. Calcium and phosphorus need to stay in balance, too, especially for growing horses. Count nutrients from every feed and supplement, not just the newest scoop.
Most horses do best on good forage, the right feed for their workload, salt, and clean water. If your horse needs more than that, find the gap first, then pick the supplement that fills it.
About Miles Henry
Racehorse Owner & Author | 30+ Years in Thoroughbred Racing
Miles Henry (legal name: William Bradley) is a professional horseman based in Folsom, Louisiana. He holds Louisiana Racing License #67012 and has spent over three decades managing Thoroughbreds at premier tracks including Fair Grounds, Delta Downs, and Evangeline Downs.
Expertise & Hands-On Experience: Beyond the track, Miles has decades of experience in specialized equine care, covering everything from hoof health and nutrition to training protocols for Quarter Horses, Friesians, and Paints. Every guide on Horse Racing Sense is rooted in this “boots-on-the-ground” perspective.
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