Dog symptom

Weight loss in dogs

See a vet today

Losing weight without trying — even while eating normally — is an important sign worth investigating. Many causes are treatable, especially when caught early.

Common causes of weight loss in dogs

  • Dental pain or trouble eating
  • Parasites or poor nutrient absorption
  • Overactive thyroid (cats), diabetes, kidney, liver, or heart disease
  • Cancer

Who's most at risk

  • Senior pets
  • Cats (hyperthyroidism, kidney disease)
  • Pets overdue for parasite prevention
  • Pets with dental disease

What you can do at home

  • Weigh your pet regularly and track the trend
  • Note appetite, energy, drinking, and stool changes
  • Don't just add more food — find out why first

When to see a vet

  • Steady or rapid weight loss, with or without a normal appetite
  • Weight loss plus increased thirst, vomiting, or diarrhea
  • Low energy, a poor coat, or muscle loss
  • An older cat eating well but losing weight (think thyroid or kidney)

When it's more serious

  • Weight loss with these signs points to a treatable disease — get bloodwork soon.
  • Significant or rapid weight loss needs a vet workup promptly.

What your vet may do

  • Full exam, weigh-in, and dental check
  • Bloodwork, urine test, and thyroid testing (cats)
  • Imaging or further tests based on results
  • Treat the underlying disease and support nutrition

Questions to ask your vet

  • What's the most likely cause given the bloodwork?
  • Should we test the thyroid and kidneys?
  • Is this manageable, and what's the plan?
  • What and how much should I be feeding?

Frequently asked questions

What causes weight loss in dogs?

Losing weight without trying — even while eating normally — is an important sign worth investigating. Many causes are treatable, especially when caught early. Common causes include: Dental pain or trouble eating; Parasites or poor nutrient absorption; Overactive thyroid (cats), diabetes, kidney, liver, or heart disease; Cancer.

Is weight loss in dogs an emergency?

See a vet today. See a vet right away if: Steady or rapid weight loss, with or without a normal appetite; Weight loss plus increased thirst, vomiting, or diarrhea; Low energy, a poor coat, or muscle loss; An older cat eating well but losing weight (think thyroid or kidney).

What can I do at home for a dog with weight loss?

Weigh your pet regularly and track the trend Note appetite, energy, drinking, and stool changes Don't just add more food — find out why first

Sources

Reviewed by the Webvet Veterinarian Team

This guide is general information, not a diagnosis, and does not replace an exam by your veterinarian. If your pet is in distress, contact your vet or an emergency clinic right away.

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