Will My Dog Lose Muscle if Neutered? (The Facts)

It is commonly believed that castration (the removal of the testicles) or spaying will cause a dog’s muscles to shrink and its bones to become brittle.

This is at least partially true.

Hormones produced in the testicles play a role in both muscle growth and bone density. However, the effects of neutering on muscle and bone are generally not as dramatic as many believe.

An animal’s diet plays a major role in how its muscles and bones respond to hormonal changes.

Muscle Loss After Neutering – The facts

There is no evidence that castrating or spaying a dog will greatly reduce muscle mass.

However, there have been instances where full-blooded male dogs who were neutered at a very young age began to exhibit less muscle mass than other intact males who reached the same age.

There are multiple theories for why this occurs, but the truth remains unknown.

It is not unheard of for dogs to show a modest reduction in muscle mass if neutered at a young age, but this is rare and the effect is usually temporary.

Neutering will not greatly reduce a dog’s muscle mass unless it is done at an unusually early age.

The fact that neutering alone will not greatly reduce the size of a dog’s muscles does not mean it should be viewed as an acceptable practice for individual dogs with naturally large muscles.

Some muscle-bound dogs are prone to various joint problems and other health issues associated with increased body weight, regardless of whether they are neutered.

Surgical removal of a dog’s testicles will not solve many of these issues in these cases.

There is no evidence for the popular claims that neutering will make a dog weak, wimpy or unhealthy.

The truth is that variable blends of genetics, environment and diet can lead to different levels of lean muscle and bone mass.

Only a pound or two difference in body weight doesn’t usually cause great changes in mass if all other factors don’t change much too.

Which types of dog breed are more likely to lose muscle if neutered?

There are a few breeds that are singled out as having a predisposition to bone and muscle problems and so could lose muscle if neutered, but the reality is that these problems are found in all breeds of dogs.

Dogs with a propensity to develop joint problems or other health issues are prone to these conditions regardless of breed.

Some dogs whose owners choose to have them neutered at a young age may start to show less muscle mass as they reach adulthood.

This is thought by some to be because the testicles produce hormones that affect muscle mass in both males and females.

On the other hand, others theorize that this result follows from an increased tendency for these breeds to develop osteosarcoma. The truth, however, remains unknown.

The same dog will lose muscle if neutered or not?

Yes and no. There are some breeds, usually purebreds, whose cross-breeds have what is known as a “low testosterone” gene.

These dogs often develop muscle and bone problems similar to those found in other breeds.

While this dog is the same type, all other factors being equal it will have less potential for health problems than an equivalent dog that lacks the low-testosterone gene.

How can I tell if my dog will lose muscle if neutered?

Define “loss of muscle” based on your own experience and expectations

It is impossible to accurately predict what will happen to a dog’s muscles if it is neutered.

What may be a significant loss in certain breeds, such as Greyhounds or German Shepherds (whose owners may be looking for a specific look), may not even be noticeable in another, say a Chihuahua.

You will need to define the effects you want in your particular words and sincerely expect that this is what you are going to get.

Some men and women who have had dogs for long enough may have seen a dog whose muscles fail rapidly after being neutered . You must decide if you are willing to accept this risk or not.

Which dogs are more at risk for muscle loss?

Like humans, all dogs have some degree of muscle tone and some degree of fat.

Fat density is not a good predictor of muscle density. A fat-free dog’s muscles will lose little if anything, whereas a heavily muscled purebred dog, may still retain some muscle mass even after being neutered.

If an owner is wanting to remove the dog’s reproductive hormones, it seems sensible that the owner should be prepared to accept any consequences of doing this.

What are the effects of neutering on a dog?

The effect of neutering on a dog’s health depends on a lot of factors.

The animal’s overall weight, whether it is an adult or a young puppy (up to 4 months old), and the type of neutering procedure performed.

Neutered dogs do not have the same potential for health problems that they would if they were intact.

This does not mean that neutered dogs are free of all risks, but there are fewer worries for owners as long as they do not subject their dogs to unnecessary trauma or other negative circumstances.

How long does it take for a dog to get back to normal after being neutered?

The recovery time after neutering is minimal for dogs if they are healthy before the surgery.

Dogs that are in good condition tend to heal quickly. If the dog is neutered at an unusually young age, it may take longer for it to return to its previous state of health.

Young pups that have been neutered should be monitored closely over the next few months, especially if there are any other dogs in the house with them.

What would cause a loss of muscle after neutering?

Neutering may affect your dog in one or more of these ways:

If your dog has lost muscle after being neutered, contact your veterinary clinic immediately.

Can neutering cause health problems?

The most basic answer is yes, your pet can get sick or develop a problem due to the neutering surgery.

Always consult your vet immediately if you suspect anything is wrong after the procedure.

Final Thoughts

Neutering a dog does not always result in a loss of muscle.

There is no way to accurately predict if your dog will lose muscle if neutered, and you must decide for yourself what is best for your pet.

If you do want to have your dog neutered, make sure it has been thoroughly researched and that the decision has been made by the entire family, not just the individual who will be paying for it.

You should also be prepared to accept any potential risks associated with it before deciding whether or not to have the surgery performed on your pet.

The important thing to remember is that there are still health benefits associated with neutering, even if you elect not to have your male dog neutered at all.

As always, speak to your veterinarian or a qualified dog trainer if you have any questions regarding neutering.




American Kennel Club


Important Note: The information provided in this article is not intended for the diagnosis/treatment of any medical conditions.

Please consult a licensed, qualified veterinarian before acting on any information provided herein.

References herein are for educational purposes only and do not necessarily constitute endorsements of the author’s opinions or recommendations.

This article does not constitute medical advice and should not be taken as such.

Always consult your veterinarian before embarking on any medical-related decisions.


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