Why Do Dogs Shed? The Reasons Dogs Lose Their Hair Throughout the Year

large chow chow dog laying on a deck

The age old question that all pet parents ask themselves as they vacuum up their dog's hair: Why do dogs shed? Well don't feel bad, scientists have been trying to figure it out for years. Here is a list of reasons why dogs might shed so much.

The question of why dogs shed puzzles even scientists -- why does their fur grow in and fall out in an endless cycle? Current science has broken down shedding into three phases: hair growth (anagen phase), a brief period of neither growth nor shedding (catagen phase), and, finally, the shedding period (telogen phase).

In some breeds, this cycle can take up to a year, whereas in other breeds, it can happen in as few as 30 days. The breeds whose cycles are longer shed less, and those whose cycles are shorter shed more. Poodles and some Terriers, for example, shed less than many other breeds due to their long shedding cycles. Labs and Huskies, on the other hand, have a shorter cycle of growth, making them heavy shedders (as any Lab owner can attest).


There are a variety of health problems for which shedding is an indicator. A healthy dog will generally shed less than a sick dog.


Strange hair loss or excessive shedding can point to:

  • Hormonal issues
  • Allergies
  • Fevers
  • Parasites
  • Chemical imbalances
  • Dietary deficiencies
  • Skin conditions
  • Stress
  • Spinal issues

Generally speaking, excessive shedding most often points to allergies or hormonal issues.


Hair loss can indicate that your dog is having an allergic reaction to something in their environment, an ingredient in their food, a new drug, or even the weather.

Just as with people, determining the source of an allergy can be tricky. Elimination is the favored method of deduction.


Excessive shedding can be a sign of hormone imbalance. An underactive thyroid, for example, will often result in dry, brittle hair that breaks and falls off. This condition can be resolved with medication.

Other hormonal issues involving the over- or under-production of testosterone, estrogen, and progesterone can cause a dog to shed more than usual.

Lactation & Pregnancy

Hormones are never in more flux than when a dog is pregnant or nursing. A nursing mother, low on energy and certain vitamins and minerals, will shed more than she typically does. Certain supplements can help, but discuss options with your vet, as some supplements can do more harm than good. Just know that some hair loss during this time is normal.


Some dog breeds will shed in response to the change of seasons -- usually once a year in spring, but sometimes in the fall as well -- by losing a whole bunch of fur all at once.

In the spring, sunlight, warmer weather, and longer days trigger a dog’s follicles to release the winter coat. Most dogs, even hardy working breeds, are now companion animals who live inside with their humans. For this reason, an extreme seasonal shedding response is less common than it used to be. Now, most dogs shed year-round.

Frequently Asked Questions

What causes a dog to shed?

Dogs shed for a variety of reasons, including natural hair growth cycles, changes in weather, stress, and underlying medical conditions. Like humans, dogs have a natural hair growth cycle. They shed old or damaged hair to make way for new, healthy hair growth. Many dogs shed more in the spring and fall as they adjust to changes in daylight and temperature. Dogs may also shed more when they are stressed or anxious, such as during a move or changes in routine. A poor diet lacking essential nutrients can lead to poor coat quality and increased shedding. Underlying medical conditions such as allergies, parasites, thyroid disorders, and hormonal imbalances can also cause excessive shedding.

How can you stop a dog from shedding?

It is important to note that shedding is a natural process for dogs and cannot be completely stopped. However, there are several ways to reduce shedding and keep your dog's coat healthy. Brushing your dog's coat regularly helps remove loose hair, distribute natural oils, and prevent matting. Regular bathing helps keep your dog's skin and coat clean and healthy. Use a mild dog shampoo and avoid over-bathing, which can dry out the skin. A balanced and high-quality diet rich in essential nutrients is important for maintaining a healthy coat. Omega-3 fatty acid supplements, such as fish oil, can help improve coat quality and reduce shedding. Dogs that are stressed or anxious may shed more, so managing their stress through exercise, play, and relaxation can help. Addressing any underlying medical conditions, such as allergies or hormonal imbalances, can help reduce shedding.

What months do dogs shed the most?

Dogs generally shed the most during seasonal changes, especially during the spring and fall months. During these times, dogs' coats adjust to changes in daylight and temperature, which triggers the shedding process. In the spring, dogs shed their heavy winter coats in preparation for warmer weather, while in the fall, they shed their lighter summer coats to make way for thicker winter coats. However, the amount of shedding can also depend on the individual dog's breed, age, health, and lifestyle. Some dogs may shed more or less than others, and some may shed year-round. It's important to monitor your dog's shedding patterns and consult with your veterinarian if you notice excessive shedding or any other changes in your dog's coat or skin.

Does brushing a dog reduce shedding?

Yes, regular brushing can help reduce shedding in dogs. Brushing your dog's coat helps to remove loose and dead hair, which would otherwise fall off around your home. By removing the loose hair from your dog's coat through brushing, you can also help to distribute natural oils throughout the coat, which helps keep the skin and coat healthy. There are many different types of brushes available for dogs, each designed to suit different coat types and grooming needs. A bristle brush is a versatile brush with short, tightly-packed bristles that work well for most coat types, especially short-haired breeds. It helps to distribute natural oils, remove loose hair and dirt, and promote a healthy coat shine. A pin brush has long, thin pins that are set further apart than a bristle brush. It works well for long-haired breeds and helps to detangle mats and remove loose hair without damaging the coat. The slicker brush is a flat brush with fine, tightly-packed wire bristles that work well for long-haired breeds with dense coats, such as Poodles or Collies. It helps to remove tangles and mats and can help to reduce shedding. Undercoat Rake has long, widely-spaced teeth and is designed to remove loose hair and undercoat from breeds with a thick undercoat, such as Huskies and Malamutes. The shedding blade has a metal or rubber blade with small teeth that are designed to pull out loose hair from the undercoat. It works well for breeds with a thick undercoat, like Retrievers and Shepherds. Furminator is a de-shedding tool that has a curved edge and a sharp metal blade that helps to remove loose hair from the undercoat. It works well for breeds that shed heavily and are especially useful during seasonal changes. Brushing is especially important for dogs that shed heavily or have long or thick coats. Depending on the breed and coat type, daily brushing or weekly brushing may be necessary to reduce shedding effectively. Regular grooming can also help you detect any skin or coat issues early, which can prevent further shedding or damage to your dog's coat.

More on Dog Shedding

Top Products to Stop Dog Shedding
Dogs That Don't Shed
Fluffy Dog Breeds

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