For a long time, Sophie’s changes were easy to overlook. She slowly gained weight, even though she didn’t eat more than the others. Her coat became greasy, dull, and flaky. And no matter how often we bathed her, the oiliness came back within days. She seemed more tired, more sluggish. I had a feeling something was off – and I’m glad I trusted that feeling.
What Is Hypothyroidism in Dogs?
Sophie has hypothyroidism, a condition where the thyroid gland doesn’t produce enough thyroid hormone (thyroxine). This hormone plays a key role in regulating a dog’s metabolism, skin health, energy levels, and weight. When there’s not enough of it, the entire system slows down.
In Sophie’s case, this hormone imbalance explains almost everything:
Her weight gain despite no change in diet
Her excessively oily coat
The flaky skin and occasional crusts
Her constant hair loss, especially after bathing
Her low energy and general “flatness”
These signs don’t appear all at once. They creep in slowly—and often get mistaken for aging or poor nutrition.
Blood Test Results: The Numbers Behind the Diagnosis
We ran a T4 (thyroxine) test and a cholesterol test. The results were clear:
T4: < 0.4 µg/dL (Normal range: 1.1 – 4.0 µg/dL)
Cholesterol (CHOL): 300 mg/dL (Normal range: 125 – 270 mg/dL)
A T4 value this low is a strong indicator of hypothyroidism. The high cholesterol reading supports it further, as thyroid problems often affect fat metabolism.
We didn’t run a TSH test (which would measure thyroid-stimulating hormone), because the symptoms and T4 results were already clear enough to begin treatment.
Treatment: Replacing What’s Missing
Sophie has now started daily synthetic thyroxine treatment. This medication simply replaces the hormone her body can’t make on its own. The dose will be adjusted over time, depending on how her body responds.
In addition to the medication, we started a skincare routine to help her coat recover:
Bathing twice a week with Sebazole shampoo (to reduce oil and yeast)
Gentle brushing daily to remove flakes and loose fur
Monitoring energy levels, weight, and appetite
What to Expect
Thyroid conditions don’t turn around overnight. It can take a few weeks before we start seeing real changes—but with the right care and consistency, dogs with hypothyroidism live full, happy lives.
If your dog is gaining weight, losing fur, or just seems “off” in ways you can’t explain, don’t ignore it. Sometimes it’s not the food. Sometimes it’s the hormones.
We’ll keep you updated on Sophie’s progress in the weeks ahead.