Can Cats Get EPI? Signs of EPI in Older Cats (And Why It’s Often Mistaken for Hyperthyroidism or Diabetes)

2026-01-13 Daniel O.

Quick Answer: Can Cats Get EPI?

Yes. Cats can absolutely get Exocrine Pancreatic Insufficiency (EPI)—and it’s likely under-diagnosed because the signs overlap with other common “older cat” conditions like hyperthyroidism and diabetes.

Most common signs of EPI in older cats include:

• Weight loss (sometimes severe)
• Chronic loose stools/diarrhea (often bulky, pale, foul-smelling)
• Sometimes increased appetite (polyphagia)—but not always
• Poor coat quality, gas, and “never quite thriving”

The gold-standard test is a blood test called serum feline trypsin-like immunoreactivity (fTLI).

Treatment follows the same logic as EPI in dogs — powdered enzymes with every meal, B12 support, and a low fiber, highly digestible diet — but the doses and the food are cat-specific.

Can Cats Get EPI? (Why This Niche Matters)

If you run an EPI education site, feline EPI is a perfect “niche within a niche” because:

1. Many owners don’t even know it exists
2. Cats are masters at hiding disease
3. The symptoms are easily blamed on “thyroid,” “diabetes,” “IBD,” or “just old age”
4. Once diagnosed, treatment can be very successful with the right plan (enzymes + B12 + diet)

And here’s the most important point:

What Is EPI in Cats?

Exocrine Pancreatic Insufficiency (EPI) means the pancreas is not producing enough digestive enzymes (and related secretions) to properly digest food. The result is maldigestion and malabsorption—your cat may eat, but nutrients don’t get broken down and absorbed well.

In cats, EPI is most commonly associated with chronic pancreatitis as an underlying cause (long-term pancreatic inflammation damaging the enzyme-producing tissue).

Why EPI in Cats Is Often Missed

1) Cats don’t always show “classic dog EPI”

Dog owners often report the classic trio:

• ravenous appetite
• weight loss
• voluminous pale stool

Cats can show this too—but feline cases can be subtle and complicated by other diseases. MSD Vet Manual notes that cats can be any age and may show weight loss and loose stools; vomiting/anorexia can occur and may reflect concurrent conditions.

2) EPI can mimic hyperthyroidism

Hyperthyroidism often looks like:

• weight loss
• increased appetite
• vomiting
• stool changes

So an older cat losing weight tends to get a thyroid test first (which is appropriate). But if thyroid is normal—or treatment doesn’t fully resolve GI signs—EPI can be overlooked.

3) EPI can mimic diabetes

Diabetes can look like:

• weight loss despite eating
• increased thirst/urination
• weakness
• sometimes stool changes due to other GI issues

Owners (and sometimes clinicians) can get pulled into a diabetes-only pathway when the real issue is maldigestion.

4) “Amylase/lipase” testing doesn’t diagnose EPI

This is a common misconception. A major feline EPI review notes that fTLI is the gold-standard and that other tests (like amylase/lipase activity) are much less sensitive/specific for diagnosing EPI.

Signs of EPI in Older Cats

Here are the most common signs—organized by what owners actually notice.

1) Weight loss (often the first red flag)

This is the most consistent theme in feline EPI discussions. Cats lose weight because they’re not absorbing calories and nutrients well.

Owner descriptions:

• “He eats but stays skinny.”
• “Her spine and hips feel sharp.”
• “He’s dropping weight even though we increased food.”

2) Chronic loose stool or diarrhea

Stool in EPI can be:

• loose, unformed
• pale or light brown
• bulky/large volume
• foul smelling

MSD Vet Manual describes feces in EPI as commonly pale, loose, voluminous, and malodorous.

3) Increased appetite (polyphagia) — but not guaranteed

Polyphagia is “classic,” but not universal in cats. Some cats show normal appetite, picky behavior, or appetite swings—especially if nausea or concurrent disease exists. EPI as a malabsorptive condition often produces weight loss with increased appetite, but presentation can vary.

4) Poor coat, dandruff, “unkempt” look

When digestion is poor, skin/coat can suffer:

• dull coat
• dry skin
• poor grooming (sometimes due to weakness or nausea)

Owners often notice the coat looks “older” fast.

5) Gas, rumbling belly, and litter box “events”

Some cats develop:

• gas
• loud GI sounds
• urgency
• messy stools

6) Vomiting or reduced appetite can happen (often due to concurrent disease)

Vomiting and anorexia can occur and may reflect other conditions present alongside EPI rather than EPI alone.

The Confusing Part: EPI vs Hyperthyroidism vs Diabetes

This is where your niche article shines. Here’s a simple comparison owners can use before they even know what tests to ask for.

Important reality: Cats can have more than one condition at once. Chronic pancreatitis, diabetes, and EPI are related pancreatic “neighbors,” and older cats commonly have overlapping issues.

So the practical goal is not guessing—it’s testing.

Video: EPI in Pets (Dogs and Cats)

This podcast episode covers the essentials of EPI, confirming that it affects both dogs and cats and explaining why lifelong therapy is necessary.

How Feline EPI Is Diagnosed (The Test to Ask For)

The gold-standard: Serum feline TLI (fTLI)

Multiple veterinary references emphasize serum fTLI as the most reliable test for diagnosing EPI in cats.

MSD Vet Manual provides a diagnostic cutoff: TLI ≤ 8.0 mcg/L in cats is considered diagnostic for EPI.

Texas A&M’s GI Lab (a major reference laboratory for GI testing) similarly shows that 0–8 µg/L is diagnostic for feline EPI and highlights that fasting is important for accuracy.

Fasting matters

Texas A&M notes the animal should be fasted 8–12 hours before the TLI sample is taken.

What about fecal tests or “digestive markers”?

They’re not the same. Fecal elastase testing has limitations, and routine fecal tests don’t diagnose EPI. Blood fTLI is the key test most commonly cited.

The “Hidden Problem” in Cats With EPI: B12 Deficiency

This is huge for feline EPI.

In cats, most intrinsic factor (needed for B12 absorption) is produced by the pancreas. MSD Vet Manual states that almost all cats with EPI are cobalamin (B12) deficient.

That means:

• even if you start enzymes,
• your cat may not fully improve without B12 support.

Treatment: What Helps Cats With EPI Feel Normal Again?

1) Pancreatic Enzyme Replacement Therapy (PERT)

This is the foundation.

MSD Vet Manual notes treatment includes pancreatic enzyme replacement therapy, and it also states that powders are more effective than tablets/capsules (especially enteric-coated products).

Powder vs pills matters in cats too

If you’re building a content cluster, this ties nicely to your “powder vs pills” dog article:

• powders mix with food
• better enzyme-food contact
• more reliable digestion support

2) Cobalamin (B12) supplementation

Because B12 deficiency is so common in feline EPI, B12 treatment is often part of standard management. MSD Vet Manual lists cobalamin supplementation as a component of EPI treatment.

Your veterinarian will choose:

• injection vs oral approach
• dosing schedule
• recheck timing

3) Diet strategy (digestibility first)

There isn’t one “magic” diet for every EPI cat, but most successful approaches prioritize:

• highly digestible food
• consistency (avoid constant switching)
• appropriate fat for that cat’s history (especially if pancreatitis is present)

What Improvement Looks Like (And How Fast)

Many owners expect overnight change. Realistic timeline:

First 1–2 weeks

• stool begins to improve (less volume, better form)
• appetite may become less frantic (if it was high)
• energy may improve slightly

Weeks 3–8

• weight gain becomes noticeable
• coat begins to look healthier
• litter box pattern stabilizes

If your cat doesn’t improve, the usual reasons are:

• enzymes not mixed/dosed correctly
• inconsistent feeding (too many changes)
• B12 deficiency not addressed
• concurrent disease (IBD, diabetes, hyperthyroidism, chronic pancreatitis)

A Simple “Should I Ask My Vet About EPI?” Checklist for Older Cats

Consider testing for EPI if your older cat has:

• ✅ Weight loss for more than 2–3 weeks
• ✅ Chronic loose stool/diarrhea
• ✅ Pale, bulky, foul-smelling stool
• ✅ Increased appetite OR appetite swings
• ✅ Poor coat / “not thriving”
• ✅ Thyroid/diabetes tests don’t fully explain the GI signs
• ✅ Known chronic pancreatitis history (common feline cause)

Then ask about:

• fTLI (fasted 8–12 hours)
• cobalamin (B12)

Trusted Resources

1. Texas A&M GI Lab — TLI Testing (Canine & Feline) Read Article

2. MSD Vet Manual — Disorders of the Pancreas in Cats (EPI) Read Article

3. Veterinary Partner (VIN) — Exocrine Pancreatic Insufficiency Read Article

4. WSAVA — Exocrine Pancreatic Insufficiency in Cats Read Article

Written by the EPI Pet Support Team — helping owners connect symptoms to the right testing and treatment, faster.