Do Supplements Help Horse Stomach Ulcers?

By Dr Duncan Houston

Horse ulcer supplements are everywhere. Powders, pellets, buffers, pectin-lecithin blends, sea buckthorn, aloe, probiotics, beta-glucans, hyaluronan, herbs, “gut health” formulas, and enough confident label claims to make the feed room look like a small pharmacy.

The reason owners reach for them is understandable. Gastric ulcers are common in performance horses, they can affect appetite, behaviour, body condition, and performance, and proper treatment can be expensive.

But the key question is simple: do supplements actually treat ulcers, or do they only support the stomach after proper treatment?

The honest veterinary answer is that some supplements may help in specific situations, especially as maintenance support after medical treatment. But they should not replace diagnosis, omeprazole, or good management when a horse has active gastric ulcers.

Quick Answer

Some horse ulcer supplements may help support stomach health or reduce recurrence after treatment, but they are not a substitute for veterinary diagnosis or proven ulcer medication. Omeprazole remains the main acid-suppressing treatment for equine gastric ulcers, and gastroscopy is the only way to confirm whether a horse has squamous ulcers, glandular ulcers, or both. (cehhorsereport.vetmed.ucdavis.edu)

Supplements are best thought of as supportive tools, not primary treatment for active ulcers.

What Are Equine Gastric Ulcers?

Equine gastric ulcer syndrome, often shortened to EGUS, refers to ulceration in the horse’s stomach.

The important part is that not all ulcers are the same. The horse’s stomach has two main regions, and ulcers in each region behave differently.

UC Davis explains that gastroscopy is the gold standard for diagnosis because it allows the vet to confirm whether ulcers are present and determine whether they are squamous, glandular, or both. (cehhorsereport.vetmed.ucdavis.edu)

That distinction matters because squamous ulcers often respond more predictably to acid suppression, while glandular ulcers can be harder to treat and may need a more tailored plan.

Why Horses Get Stomach Ulcers So Easily

Horses are designed to graze for much of the day. Their stomach produces acid continuously, even when they are not eating.

Modern management often works against that natural rhythm. Many horses are stabled, fed in meals, worked hard, travelled frequently, and exposed to long gaps without forage. That can leave the stomach more exposed to acid.

Exercise can also contribute. MSD Veterinary Manual notes that exercise may increase abdominal pressure and push acidic stomach contents into the more acid-sensitive upper stomach. (MSD Veterinary Manual)

Common risk factors include:

• Long periods without hay or pasture

• High-starch or high-grain diets

• Intense training

• Travel and competition stress

• Stall confinement

• Social stress

• Limited turnout

• NSAID use, especially when excessive or prolonged

• Previous ulcer history

The issue is rarely one single cause. In practice, ulcers usually develop when several risk factors stack together.

What Actually Treats Horse Stomach Ulcers?

The main proven medical treatment for equine gastric ulcers is acid suppression, most commonly with omeprazole.

GastroGard® is an FDA-approved omeprazole oral paste labelled for treatment of gastric ulcers in horses and foals 4 weeks of age and older. The labelled treatment course is once daily for 4 weeks at 4 mg/kg, with a lower maintenance dose used for prevention of recurrence when indicated. (DailyMed)

A current update is important here. Older articles often state that GastroGard® is the only FDA-approved omeprazole oral paste for horses. That changed on April 6, 2026, when the FDA approved Gastrobim as the first generic omeprazole oral paste for treatment and prevention of gastric ulcer recurrence in horses and foals 4 weeks of age and older. (U.S. Food and Drug Administration)

That does not make supplements irrelevant. It simply puts them in the right place.

Medication treats active ulcers. Management reduces recurrence risk. Supplements may support the plan.

Do Supplements Heal Active Ulcers?

Usually, no.

A supplement should not be relied on as the main treatment for confirmed gastric ulcers, especially if the horse has moderate to severe ulcers, glandular disease, weight loss, recurrent colic signs, or marked behaviour change.

A better way to think about supplements is this:

The mistake I see most often is owners trying supplement after supplement while the horse is still painful, losing condition, or showing persistent signs. That can waste time and money, and the horse still has a sore stomach at the end of it.

What Does the Research Say About Ulcer Supplements?

The research is mixed. Some products have early or limited evidence. Many have little more than testimonials.

SmartGut® Ultra

One study looked at a pelleted supplement, SmartGut® Ultra, in horses after omeprazole treatment. The study found that supplementation may help protect the non-glandular stomach from recurrence of ulcers after omeprazole treatment in stall-confined horses undergoing intermittent feeding. (beva.onlinelibrary.wiley.com)

That is useful, but it needs to be interpreted carefully.

It does not prove that SmartGut® Ultra replaces omeprazole. It does not prove that all ulcer supplements work. It does not prove the same effect for every horse, every management system, or every ulcer type.

It suggests a possible role as post-treatment support, especially for recurrence risk in non-glandular ulcers.

Other supplement ingredients

Some supplements use ingredients such as pectin, lecithin, beta-glucans, hyaluronan, antacids, sea buckthorn, aloe, probiotics, or buffering agents.

Some of these ingredients are biologically plausible. A few have small studies or early evidence. But that is not the same as proving they heal active ulcers in real-world performance horses.

MSD Veterinary Manual notes that antacids have not yet been proven effective for healing or preventing gastric ulcers in horses, and that omeprazole remains the treatment of choice for acid suppression. (MSD Veterinary Manual)

So the practical conclusion is simple: supplements may help some horses in some situations, but they are not equivalent to prescription ulcer therapy.

Why Supplement Claims Need Caution

Animal supplements are not regulated like prescription medications.

In the United States, the FDA does not recognize animal dietary supplements as a special category under the same framework used for human dietary supplements. Products marketed for animals are regulated as either animal food or animal drugs depending on their ingredients and intended use. (U.S. Food and Drug Administration)

That matters because a label can sound impressive without proving the product treats disease.

Be especially cautious of claims like:

• “Heals ulcers naturally”

• “Replaces omeprazole”

• “Stops ulcers permanently”

• “Clinically proven” without a clear study reference

• “Vet recommended” without explaining evidence

• “Works for glandular and squamous ulcers” without proper data

A good supplement company should be able to explain what is in the product, why it is there, what evidence supports it, and what the product is not designed to do.

How Worried Should You Be?

Ulcers are not always an emergency, but they should not be ignored.

The real concern is not just whether the horse has ulcers. It is whether you are treating the right type of ulcer with the right plan.

What Else Can Look Like Ulcers?

This is where veterinary reasoning matters.

Many horses with ulcers are described as girthy, grumpy, reluctant under saddle, picky with feed, poor doers, or not quite right. But those signs are not specific.

Possible rule-outs include:

• Hindgut disease

• Dental disease

• Back pain

• Saddle fit problems

• Lameness

• Ovarian pain

• Parasites

• Chronic pain elsewhere

• Poor training fit

• Stress or social conflict

• Low-grade colic

• Liver or systemic illness

• Feed intolerance or diet imbalance

This is why gastroscopy is so valuable. It stops the guessing. It tells you whether ulcers are present, where they are, and how severe they are.

When Is This an Emergency?

Most adult horses with suspected ulcers do not need emergency treatment if they are still eating, bright, passing manure, and comfortable.

But call a vet urgently if your horse has:

• Colic signs

• Repeated lying down or rolling

• Severe depression

• Complete refusal to eat

• Black, tarry, or bloody manure

• Rapid weight loss

• Fever

• Signs of dehydration

• Severe abdominal pain

• Worsening signs despite treatment

• Any concerning ulcer signs in a foal

Foals are a special concern. MSD Veterinary Manual notes that ulcer complications are most frequent and severe in foals, and that clinical signs in foals can indicate severe disease requiring immediate evaluation and treatment. (MSD Veterinary Manual)

What Should You Do Next?

1. Do not diagnose ulcers from behaviour alone

Behaviour can give clues, but it cannot confirm ulcers.

A horse that pins its ears when girthed may have ulcers. It may also have back pain, poor saddle fit, lameness, ovarian pain, learned anxiety, or another medical issue.

If signs persist, get the horse assessed.

2. Use gastroscopy when possible

Gastroscopy is the best way to know what you are treating. It also helps separate squamous disease from glandular disease, which changes expectations and treatment planning. (cehhorsereport.vetmed.ucdavis.edu)

3. Treat active ulcers properly

If ulcers are confirmed or strongly suspected, follow your vet’s treatment plan. For many horses, that means omeprazole. For glandular disease, the plan may include additional medications or a longer course.

Do not try to “supplement your way through” a horse that needs medical treatment.

4. Use supplements strategically

Supplements may make the most sense:

• After omeprazole treatment

• During high-risk travel or competition periods

• In horses with a history of recurrence

• When management risk factors cannot be fully removed

• As part of a broader stomach support plan

• When the product has actual evidence behind it

5. Fix the management problem

This is the boring part, which is exactly why it matters.

If the horse goes back to long fasting periods, high-starch meals, hard work on an empty stomach, limited turnout, stress, and repeated travel, ulcers are more likely to return.

A supplement cannot outwork bad management. That is asking a scoop of powder to do a veterinarian’s job and a stable manager’s job at the same time.

Common Mistakes Owners Make With Ulcer Supplements

Using supplements instead of diagnosis

If the horse has persistent signs, guessing with supplements can delay proper care.

Treating all ulcers as the same

Squamous and glandular ulcers are different. A product that may support one situation may not solve another.

Stopping omeprazole too early

A horse may look better before ulcers have fully healed. Stopping early can increase recurrence risk.

Ignoring dosing timing

Omeprazole works best when given correctly. Giving it with feed or at the wrong time can reduce effectiveness.

Believing testimonials over evidence

A glowing review is not the same as a controlled study.

Forgetting the forage

Forage access, meal timing, turnout, stress reduction, and workload changes often matter more than the supplement.

How To Reduce Ulcer Recurrence

The strongest prevention plan is not glamorous. It is consistent.

Useful steps include:

• Provide forage for as much of the day as possible

• Avoid long periods without hay or pasture

• Reduce large high-starch concentrate meals

• Feed smaller, more frequent meals where practical

• Avoid intense exercise on an empty stomach

• Consider alfalfa before work if appropriate for the horse

• Increase turnout where possible

• Reduce unnecessary travel stress

• Keep routines consistent

• Review NSAID use with your vet

• Build rest days into hard training programs

• Recheck horses that relapse quickly

UC Davis lists management changes such as frequent forage, reduced grain and concentrates, reduced stress, turnout, and careful anti-inflammatory use as part of ulcer prevention and management. (cehhorsereport.vetmed.ucdavis.edu)

Are Supplements Ever Worth Using?

Yes, but only when the role is realistic.

A supplement is more worth considering when it has:

• Published research in horses

• Clear ingredients and doses

• A realistic claim

• Good palatability

• No obvious interaction with the horse’s medications

• A role alongside treatment, not instead of it

• A vet who agrees it fits the case

For example, SmartGut® Ultra has some evidence for reducing recurrence of non-glandular ulcers after omeprazole treatment in a small study. That makes it more interesting than products with only marketing claims. But it still belongs in the “supportive maintenance” category, not the “primary treatment for active ulcers” category. (beva.onlinelibrary.wiley.com)

FAQs About Horse Ulcer Supplements

Can supplements cure horse ulcers?

Usually, no. Supplements may support stomach health or help reduce recurrence risk, but active gastric ulcers should be managed with veterinary diagnosis, appropriate medication, and management changes.

Is omeprazole better than supplements?

For active squamous gastric ulcers, yes. Omeprazole is much better supported as a treatment. Supplements may have a role after treatment or during high-risk periods.

Should I use SmartGut® Ultra after omeprazole?

It may be worth discussing with your vet, especially for horses with recurrent non-glandular ulcers. A small study suggests it may help reduce recurrence after omeprazole treatment, but it should not replace medical therapy. (beva.onlinelibrary.wiley.com)

Can a horse have ulcers and still eat normally?

Yes. Some horses with ulcers continue eating, especially if signs are mild or intermittent. Poor performance, girthiness, weight loss, dullness, mild colic signs, or behaviour change can still justify investigation.

Are glandular ulcers harder to treat?

Often, yes. Glandular ulcers can involve problems with the stomach’s protective mechanisms, not just acid exposure. They may need a more tailored veterinary plan than squamous ulcers.

Final Thoughts

Horse ulcer supplements are not useless, but they are often oversold.

The safest way to use them is strategically: after diagnosis, alongside proper treatment, and as part of a management plan that reduces the reasons ulcers developed in the first place.

If your horse has active signs, start with the bigger questions. Does this horse actually have ulcers? Are they squamous, glandular, or both? Is omeprazole needed? Is the medication being given correctly? Are feeding, training, travel, turnout, NSAID use, or stress keeping the problem alive?

Supplements can support the answer. They should not be the whole answer.

The best ulcer plan is still built on the basics: confirm the problem, treat it properly, feed the horse like a grazing animal, reduce unnecessary stress, and use supplements only when they genuinely strengthen the plan.

If you are unsure whether your horse’s signs fit gastric ulcers, or you want help deciding whether a supplement belongs in the plan, ASK A VET™ can help you work through the safest next step.