Insulin dysregulation in horses: a new epidemic or a new perspective?

Lately, something has caught my attention.

When I look through recent research on equine nutrition, metabolism and laminitis, the same topic keeps appearing: insulin dysregulation.

One study follows another. Researchers are looking at new diagnostic tests, the insulin response to different sugars, the role of gut hormones, differences between breeds, sport horses, PPID, corticosteroids and potential medications.

In the autumn of 2026, an entire masterclass for veterinarians will even be devoted to the subject. Not just a single lecture, but a full series covering diagnostics, nutrition and exercise, acute and chronic laminitis, pharmacological treatment and owner compliance.

This raised the question: why is insulin dysregulation suddenly receiving so much attention? Are there suddenly many more horses with dysregulated insulin metabolism? Or are we looking at a problem that has always been there through a new lens?

The condition is not new. Our understanding of it is.

For a long time, the focus was mainly on insulin resistance. In this condition, the body becomes less sensitive to insulin. The pancreas compensates by producing more insulin, allowing glucose to still be taken up from the bloodstream.

The familiar picture went with it: the easy-keeping pony, overweight, with a hard cresty neck and recurrent laminitis. The horse had Equine Metabolic Syndrome, was insulin resistant and needed to lose weight.

That picture turned out not to be entirely wrong, but it was too limited. Not every overweight horse has insulin dysregulation, and not every horse with insulin dysregulation is overweight.

Moreover, after consuming sugar, a horse may show an extremely high insulin peak without there being clearly demonstrable insulin resistance at that time. Elevated basal insulin concentrations, an exaggerated insulin response after a meal, and delayed insulin clearance can also be part of the problem.

That is why the term now used is insulin dysregulation.It is not simply another term for insulin resistance, but a broader description of disturbed insulin regulation. This change in terminology has also shifted the direction of research.

The question is no longer simply why body tissues become less sensitive to insulin. Researchers are now also looking at how much insulin the pancreas produces, how quickly insulin is cleared from the bloodstream, and the signals from the gut that stimulate insulin secretion after food intake.

Insulin turned out to be more than just a measurement value.

Interest increased especially when it became clear that elevated insulin concentrations are not merely a harmless laboratory finding.

In experimental studies, laminitis could be induced by maintaining markedly elevated insulin concentrations over a prolonged period while blood glucose remained within normal limits. It was therefore not the high glucose that damaged the hoof lamellae. The hyperinsulinaemia itself was capable of triggering the process.

That fundamentally changed the role of insulin.

Insulin was no longer merely an indication that something was going wrong in metabolism. It became a central risk factor for endocrinopathic laminitis.

In the ECEIM-consensus over Equine Metabolic Syndrome In the 2019 ECEIM consensus statement on Equine Metabolic Syndrome, insulin dysregulation was therefore identified as the most important underlying risk factor.

Recent scientific reviews estimate that around 90% of laminitis cases are associated with an endocrine disorder and insulin dysregulation. This means that, when dealing with laminitis, we should not look only at grass, obesity or PPID, but also at the way the horse regulates insulin. This is not merely a semantic difference. It determines what we investigate, which horses we test, and what treatment and prevention are focused on.

We are probably missing horses.

A second reason for the growing interest is that insulin dysregulation appears to be less easy to recognise than previously thought.

A horse may have a normal basal insulin concentration yet still show an abnormally high insulin response after eating. If only a single fasting blood sample is taken, such a horse may therefore incorrectly be considered normal.

A study published in July 2026 involving 180 sport horses makes this strikingly clear. In this selected group, 41 horses — 22.8% — were diagnosed with insulin dysregulation using an oral sugar test.

Only 11 of those 41 horses had elevated insulin concentrations before the test. The other 30 were only identified once their insulin response following sugar administration was measured.

Appearance also proved to be an unreliable predictor of risk. The study was conducted in a selected group of sport horses that either presented to a university clinic for orthopaedic examination or were kept at participating yards. The figure of 22.8% therefore cannot simply be extrapolated to the wider sport horse population.

But the study does show something important: insulin dysregulation is not necessarily limited to the overweight pony with a hard cresty neck. And a normal basal insulin concentration does not rule it out. That opens up a much broader field of research.

How many horses are currently being missed? Which horses should undergo dynamic testing? When is an oral sugar test indicated? How much sugar should be administered? When should the blood sample be taken? And which cut-off value should be used for the laboratory method employed?

Diagnostics are less straightforward than a single number.

Insulin is not a static value. Its concentration is influenced by what and when the horse has eaten, the composition of the forage, the season, exercise, stress, body condition, age, breed, PPID and certain medications.

In addition, different laboratory assays do not necessarily produce exactly the same results. A cut-off value established for one analytical method cannot automatically be applied to another.

Dynamic tests are also still evolving. Researchers are comparing different doses, sampling times and types of sugar. At the same time, work is underway to develop tests that can be performed more quickly and practically at the yard.

That is why continuing professional education is essential. The science has evolved too rapidly to keep relying on the old approach of a single fasting insulin measurement in a visibly overweight pony.

But there is something else at play.

Once a condition becomes treatable, interest in it changes.

For a long time, the treatment of insulin dysregulation consisted mainly of management. The ration was adjusted, sugar and starch intake were restricted, excess weight was addressed, and exercise was gradually introduced when the horse was physically able to tolerate it.

Medications such as metformin and levothyroxine were sometimes used, but results in horses have been inconsistent. There was no medication licensed for use in horses specifically to treat hyperinsulinaemia.

In recent years, this has begun to change with growing interest in SGLT2 inhibitors, also known as gliflozins. These drugs inhibit glucose reabsorption in the kidneys, causing more glucose to be excreted in the urine and reducing the amount of insulin required to regulate blood glucose.

This does not involve just a single drug.

Among others, ertugliflozin and dapagliflozin are already being used off-label in horses with severe or difficult-to-control hyperinsulinaemia. Bexagliflozin is now also being investigated. Early studies and clinical case series suggest that several drugs in this class can reduce insulin concentrations in horses.

However, this does not mean that all gliflozins are interchangeable, or that their efficacy and safety in horses have already been sufficiently established.

The available studies vary considerably in design, dosage, treatment duration and patient population. Some have been conducted in horses with naturally occurring insulin dysregulation, others in healthy horses or in horses that developed a temporarily increased insulin response following corticosteroid administration. Many studies also involve small sample sizes, retrospective data or compounded formulations.

In addition, there are important safety considerations.

Because glucose is lost through the urine, these drugs affect not only insulin regulation but also energy metabolism. Increases in triglyceride concentrations have been reported in treated horses. This requires particularly careful case selection and monitoring in horses that are eating less, losing weight rapidly or are prone to hyperlipaemia — a serious elevation of blood lipid concentrations.

Within this development, velagliflozin occupies a unique position because a veterinary product specifically for horses has been developed based on this drug.

In Great Britain, Scovella, an oral solution containing velagliflozin, received a limited marketing authorisation in April 2026 for the treatment of hyperinsulinaemia in horses and ponies that have responded inadequately to adjustments in housing, diet and exercise.

The UK product information emphasises that the drug does not replace good management. Insulin dysregulation should be confirmed before treatment, and appetite, body condition and triglyceride concentrations, among other parameters, should be monitored during treatment.

For the European Union, the assessment took a different course. On 18 June 2026, the European Medicines Agency issued a negative opinion on the authorisation of Scovella. According to the assessment committee, the submitted data did not provide sufficient evidence that the balance between efficacy and risk was favourable.

That does not automatically mean that velagliflozin is ineffective. It means that, according to the European assessors, the available dossier did not yet provide sufficient evidence to support a positive marketing authorisation.

And that is precisely where a strong incentive for further research emerges. Which gliflozin works best in horses? What dose is effective without unnecessarily disrupting energy metabolism? Which horses are suitable candidates for treatment? How long can or should treatment continue? And which blood parameters should be monitored during treatment?

Once an entire class of drugs appears clinically useful, and one compound is also moving towards veterinary registration, accurate diagnosis becomes increasingly important — both clinically and commercially. This creates a need for standardised testing protocols, clear treatment criteria, safety monitoring and veterinarians who can correctly recognise and treat insulin dysregulation. It would therefore be naïve to assume that pharmaceutical development is completely separate from the current wave of research and continuing professional education.

That does not make the scientific interest suspect. The link between hyperinsulinaemia and laminitis had already been demonstrated before gliflozins came into use in horses. It is therefore entirely plausible that the possibility of pharmacological treatment is now further fuelling scientific and clinical interest.

So, are we dealing with a new epidemic?

We do not know.

There are indications that insulin dysregulation is more common than previously thought. However, an increase in diagnoses does not automatically mean that the condition itself has suddenly become much more prevalent.

When we start testing different groups of horses, use more sensitive tests and apply a broader definition, we will naturally identify more cases.

At the same time, modern horse management may make a predisposition to insulin dysregulation more apparent. Many horses are consistently offered more energy and non-structural carbohydrates than they need, while getting less exercise. Horses are also living longer, which means that PPID - and the combination of PPID and insulin dysregulation - may play a role more often. The two explanations are therefore unlikely to be mutually exclusive.

We are dealing with horses that genuinely develop a metabolic problem as a result of predisposition and management. But we are also looking through a new lens, allowing us to recognise cases that might previously have been described as “sensitive to grass”, “an easy keeper” or “unexplained laminitis”.

What does this mean for nutrition?

The arrival of potential medication does not change the fundamentals.

The official product information also makes it clear that medication comes only after management measures. Scovella is intended for horses that respond inadequately to changes in management and exercise, and it explicitly does not replace an appropriate ration, suitable housing or sufficient exercise.

The intake of sugar and starch can trigger a strong insulin response. If we only try to lower insulin with medication without looking at the amount and type of carbohydrates the horse is consuming, we may be treating a number rather than necessarily addressing the daily trigger.

A label stating “low in sugar” or “low in starch” is not enough. What matters is the total intake, the amount consumed per meal, the forage, the overall energy balance, body condition, opportunities for exercise and the individual horse’s response. A diagnosis therefore does not automatically lead to one standard ration.

The ration of an obese pony with little exercise requires a different approach from that of a lean sport horse with an exaggerated insulin response after eating. Likewise, an older horse with PPID, dental problems and loss of muscle mass cannot simply be placed on a strict weight-loss ration because insulin concentrations are elevated.

Diagnostics and nutritional analysis should complement one another. A ration analysis cannot diagnose insulin dysregulation. But a blood test cannot explain why the current ration is causing problems for this particular horse, nor how it can be adjusted safely.

A new lens should bring things into sharper focus.

The growing attention to insulin dysregulation is therefore no coincidence. Scientific research has identified hyperinsulinaemia as a central factor in the development of endocrinopathic laminitis. New studies show that horses may be missed when we rely solely on appearance or a basal insulin concentration. At the same time, dynamic testing is being further refined, several gliflozins are being investigated or used off-label in horses, and in Great Britain the first product specifically licensed for horses is now available.

As a result, insulin dysregulation is becoming increasingly important scientifically, clinically and commercially. That makes the subject rightly relevant. But it also carries a risk: that after years of underdiagnosis, we swing too far the other way and start looking for insulin dysregulation behind every fat deposit, every stiff step or every abnormal blood result.

A new lens is only useful if it brings the picture into sharper focus.

The challenge, therefore, is not to suddenly regard every horse as a metabolic patient. The challenge is to recognise insulin dysregulation where it is genuinely present, investigate correctly what is maintaining it, and then look beyond the laboratory value alone.

Because even with a drug available as part of treatment, the day-to-day approach still begins with what is in the feed bucket and out in the pasture.