Hypothyroidism is one of the most common endocrine disorders in dogs, causing lethargy, weight gain, skin problems, and mental dullness that significantly compromise quality of life when undiagnosed.
Hypothyroidism causes progressive, often subtle welfare compromise that is easily attributed to normal aging. Affected dogs experience lethargy and reduced activity, mental dullness affecting their interest and engagement with life, cold intolerance, and skin and coat changes including hair loss. Many dogs live with undiagnosed hypothyroidism for months or years, experiencing preventable chronic suffering. Treatment with oral levothyroxine is simple, affordable, and dramatically effective — most dogs show remarkable improvement within weeks. Regular thyroid screening in predisposed breeds at middle age enables early intervention.