What are the symptoms of hypothyroidism in dogs?

What are the symptoms of hypothyroidism in dogs?

Health & Safety

The thyroid glands are located either side of your dog’s neck, and are responsible for moderating your dog’s metabolism, regulating their hormones, and keeping your dog’s digestive system running smoothly. They also help to dictate how much your dog need to eats, their healthy weight, and how effectively they are able to process food and get the appropriate nutrients from it.

However, if your dog’s thyroid glands aren’t working properly, this can cause all manner of upsets and anomalies to develop, and which can make your dog quite ill. This can in its turn be caused by a range of different things from tumours and cancers to hormone imbalances and much more, and may develop as a secondary complication of another underlying health condition too.

Many thyroid problems in dogs can be managed or treated successfully once diagnosed and in some cases, even reversed and cured fully – but before this can happen, your vet needs to be able to diagnose the problem, and this itself relies upon you as the dog’s owner spotting that something is up and seeking help.

Overactive or underactive thyroid glands respectively can cause a range of symptoms in dogs, and an underactive thyroid gland is a much more common canine health issue than an overactive one.

An underactive thyroid gland is called hypothyroidism, in contrast to an overactive thyroid gland, which is called hyperthyroidism.

Hypothyroidism is the name given to a health condition in which the thyroid gland doesn’t work as efficiently as it should do, and this can lead to a range of systemic problems for your dog that can cause a number of wide-ranging changes throughout their bodies.

These can be quite variable in presentation from dog to dog depending on a number of factors, but in this article, we will share the most common symptoms of hypothyroidism in dogs, to help you to identify the issue if your own dog should develop an underactive thyroid gland for any reason.

Read on to find out the most common symptoms of hypothyroidism in dogs.


Dogs that have an underactive thyroid gland won’t have an awful lot of energy, as hypothyroidism means that the body cannot process the calories it gets from food into fuel to power your dog’s day to day life.

This means that a dog with hypothyroidism will tend to be lazy and lethargic, and this change will tend to develop over a moderate period of time rather than happening overnight. Your dog might have a lower than normal tolerance for and interest in play and exercise, get tired more quickly, and not be able to walk as far as normal.

They will also probably spend more time asleep, and appear slower to respond to you and less interested in the things they used to enjoy.

Increased thirst

Any health condition that affects the hormones like hypothyroidism does can have a knock-on effect on all manner of other bodily processes, and dogs with an underactive thyroid gland will potentially begin to drink more water than normal.

Increased urine output

Because your dog’s body is signalling to them that they need more water than they really do, that excessive water intake will also result in your dog needing to pee more than normal, which may manifest as needing to go out to the toilet more often, producing more urine each time they go, or inappropriately urinating in the house if they are unable to go out when they need to.

Unexplained weight gain

If your dog is piling on the pounds but isn’t eating any more than usual, hypothyroidism might be the culprit. This is because of the connection between the thyroid hormones and how your dog’s body processes food, and sends signals back and forth about the amount of food it needs and has available to use.

Hypothyroidism or an underactive thyroid gland means that the thyroid isn’t working as efficiently as it should be to process the food the body gets, which results in weight gain without a correlating increase in food intake.

Changes to the texture of the skin

Hormone conditions can cause a broad and varied range of symptoms in your dog, and hypothyroidism usually results in some type of changes to the texture and tone of the skin once it has progressed to a certain stage.

Often this results in your dog’s skin feeling dry, papery and fragile, and more prone to injury and breaking, but it can also cause the skin to feel dirty, tacky or greasy even when it is clean and freshly bathed, or be prone to developing unexplained infections or irritations.

Loss of fur

Just as hypothyroidism can affect your dog’s skin, so too can it affect the coat. This commonly causes fur loss in patches, particularly around the flanks and base of the tail, and it may also change the texture and quality of your dog’s fur, making them look unkempt and generally in poor condition.

Advanced symptoms

In many cases, hypothyroidism in dogs needs to be presenting with a lot of symptoms before it becomes evident to the dog’s owner that something is amiss, because the symptoms of hypothyroidism in dogs tend to be progressive and take time to become obvious, particularly to people who see the dog every day.

However, generally most owners will pick up on several such symptoms and contact the vet before the condition becomes so acute as to cause more obvious and dramatic issues, but if this is not the case, hypothyroidism can lead to more acute symptoms. These can include nerve problems that alter your dog’s temperament and behaviour, and can even lead to them having problems walking and getting around.

At its most acute, hypothyroidism in its final stages can result in coma and ultimately, death – but if identified and intercepted early enough and the appropriate treatment or management protocol begun, the condition can usually be managed or treated effectively to restore the dog’s quality of life.

Newsletter icon
Get free tips and resources delivered directly to your inbox.


Pets for StudWanted Pets

Accessories & services


Knowledge Hub


Support & Safety Portal
All Pets for Sale