Ask Seth: Hypothyroidism in Dogs

I have a 10-year old Lab that is overweight and has become depressed. His hair has thinned, and he just wants to nap. Friends have said it may be thyroid. Is that true?



I have a 10-year old Labrador Retriever that is overweight and has become depressed. I have noticed that his hair is thinning and he has a lot more dandruff. All he wants to do is nap. When I take him for his walks he can barely make it half the distance he used to. Some people have said that he may have a thyroid problem. Does this sound right?


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I would first recommend seeing your veterinarian for a full physical, and even having some blood work done. Blood work can help determine if your dog has a condition called hypothyroidism. Signs of this disorder include:

  • lethargy
  • lack of interest in play
  • napping
  • weight gain
  • dry skin
  • hair loss
  • depression

Hypothyroidism usually occurs between 4 and 12 years of age. If your dog has a positive diagnosis for hypothyroidism, the treatment is simply a daily dose of a synthetic thyroid pill called levothyroxine. A sample of blood for an analysis will assess effective doses and may need adjustment periodically. This treatment is relatively inexpensive and will be life long. The signs usually clear up with proper treatment. If your vet determines a negative diagnosis for hypothyroidism, your vet will have a good start in determining what is causing this behavior.


Seth Mayersohn, CVT


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