Hypothyroidism is the most common endocrine disorder in dogs, causing weight gain, lethargy, and skin problems that significantly reduce quality of life when not properly diagnosed and treated.
Hypothyroidism causes a progressive decline in dog quality of life that is often mistaken for normal aging. A hypothyroid dog experiencing lethargy, weight gain, cold intolerance, and poor coat condition is not simply getting older — it is experiencing the effects of inadequate thyroid hormone on virtually every metabolic process. These dogs feel chronically unwell in ways that affect activity, play, and their ability to engage with their environment and family. Diagnosis is straightforward with blood testing, and treatment with daily levothyroxine is inexpensive and highly effective — making hypothyroidism one of the most completely and easily reversible welfare conditions in companion dogs.