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10 Pros and Cons of Neutering Your Dog

Neutering your dog might be among the most important health decisions you’ll ever make for your dog.

First of all, what is neutering? Neutering is how dog owners commonly refer to the castration of the male dog. However, spaying a female can also be called neutering.

For the sake of this debate, we’ll take both into consideration but focus a bit more on the male procedure.

Even though the surgery itself is far easier for males, it’s sadly the procedure that’s most often falsely recommended by conventional vets.

There are pros and cons to everything, so we’ll look at both sides of the coin (playing devil’s advocate since I’m strongly against neutering when it happens too early – which is so incredibly often).

Sometimes neutering can make sense and sometimes it’s medically necessary.

However, before you rush any decision, read the full guide to avoid destroying your dog’s hormones and health for nothing but hope of changing a behavior that requires a training fix, not a medical fix.

5 Reasons Why You Shouldn’t Neuter Your Dog

Many dog owners don’t even know the health risks related to neutering.

If you ask your vet, he or she will probably say that it’s a safe procedure, that anaesthesia has advanced a lot, and if you have a male dog, they’ll tell you how easy that procedure really is and how often they perform it.


The procedure itself does carry risk (as any anesthesia does) but that may be minimal compared to the long-term risks.

Many of these risks are rooted in behavior, but some are related to growth issues or cancer.

If you have a behavioral issue, don’t fully rely on your vet. Get their opinion but just because they say your dog’s nasty humping will vanish once neutered, doesn’t mean that a) it’s a healthy choice to neuter and b) it doesn’t even mean that the behavior will really be fixed.

A vet is a vet, not a behaviorist.

Trainers or behaviorists can take care of many of the issues that plague dog owners. You can do it yourself, depending on the issue and its cause.

Let’s dive into the health risks related to neutering your dog.

1. No solution for behavior issues

Too many people think that it will magically solve all their dog’s behavior issues.

Neutering cannot completely erase testosterone from your dog and behavior mostly comes from training and genetics.

Humping, mounting, excessive sniffing, restlessness around females – all these have to be examined closer to really decide whether or not neutering could potentially help before the procedure is done.

However, some dog owners trace back unrelated behaviors and wrongly connect these behaviors to not being neutered. Among them is growling when petted or being “bad” around other dogs or whatnot as a factor that decides that the dog shall be neutered which is, quite frankly, ridiculous.

I have a whole section at the bottom dedicated to what exactly you can expect after neutering your dog.

2. They could become more aggressive

I know that this completely contradicts everything that you have heard about neutering.

But studies have shown that neutering your dog can possibly lead to more aggression, food guarding, and fear, especially when it comes to leash reactivity.

I’d recommend making sure to consult your vet about this topic because there is no one size fits all and it depends on your specific situation, but sadly this is exactly what vets recommend for behavioral issues.

Vets are incredible and they have many tools, but more often than not, their toolbox doesn’t contain something to work on behavioral issues so they resort to fiddling with the hormones.

Not all vets are properly educated on this topic which is why it’s important to form your own opinion and check the research behind all arguments. If you have a vet that’s open to this, that’s great!

Time and time again, dog owners had an issue, get their dog fixed and then come to me (and read this article too late) stating that they feel like the problem has worsened.

3. Increased risk of joint issues

If your puppy is neutered at an early age, he or she can develop joint issues and growth problems.

It can cause the leg bones to grow unevenly and may result in hip dysplasia or bone cancer.

Certain breeds like the Rottweiler or GSD are prone to joint issues, but no matter what breed you have, waiting until they’re fully grown is absolutely mandatory.

So when is it safe to neuter a dog? After their bone growth has finished. We’ll dive deeper into that below.

4. Increased risk for obesity

Neutering not only changes the dog’s hormones but also the metabolism.

If you continue feeding your dog the same sort and amount of food after neutering, he could be at high risk of getting overweight and therefore developing joint diseases.

As many things on this list, this is different for all dogs though and needs to be judged on a case-by-case basis.

Of course, one could argue that you can just lower the food intake but it’s not always that easy and depends on the distribution between fats, protein, and carbs (which usually shouldn’t make up much of a dog’s diet anyway).

5. Increased risk of hypothyroidism

This disease is caused by the sudden loss of reproductive hormones in a canine body. Low thyroid levels can result in lethargy and weight gain or even obesity.

Although it can be treated by giving your dog certain supplements for the rest of his life, that’s not what dog owners strive for when they let their dogs get neutered.

Here’s also a helpful video resource by a vet who dives deeper into why neutering may not be the best choice for you.

As you can see, the benefits of not neutering a dog include less risk of developing joint issues, bone cancer as well as diseases contributing to hip dysplasia such as obesity and hypothyroidism.

What is the Best Age to Neuter a Dog?

If you have a good reason to neuter your dog, the general consensus is that the best age to neuter a small to medium-sized male dog is after they are at least 1 year old.

Large or giant dog breeds should be at least 2 years old.

Neutering a dog prior to this is associated with a variety of health problems.

Beyond waiting until your dog is at least a year old, the exact age that is best to neuter your dog may vary with your individual dog, including their size, breed, temperament, and health history.

There are still reasons why some dogs are neutered earlier, the most common being rescues and shelters seeing the results of irresponsible dog owners who breed rescues which can be avoided through neutering.

There are also some health concerns that would cause a dog to be better off neutered, including retained testicles. However, these are relatively rare. I’ll go into more detail below on why it may be in your dog’s best interest to leave them intact.

When to Neuter a Large Breed

If you have a large or giant breed dog, you may especially want to consider waiting longer to neuter your dog.

Many of the problems associated with early neutering occur because hormones are removed before the dog is finished growing, and a large or giant breed dog may still be growing until 18-24 months of age.

It’s safest to wait to neuter a large breed dog until they are fully grown, at a minimum.

Fully grown is considered to be when the dog’s growth plates have closed, which takes longer the larger the dog.

Many Golden Retrievers are considered fully grown at about 1 year of age, so for the purposes of this study, early neutering was considered anything that happened before 1 year, and late neutering was anything after that.

In some cases, neutering at any age caused an increase in musculoskeletal health problems.

However, it was always the case that neutering before 1 year drastically increased the risks!

What Happens if you Neuter a Dog Too Early?

First of all, what is considered early neutering?

Early neutering is usually considered neutering before physical maturity, which happens around 1 year of age for most dogs (although it can be up to 2 years for large and giant breeds).

Based on “studies” like this, they cite 3-4 months for females and 6 weeks of age for males which is absolutely ridiculous if you’re controlling for more than one health issue.

Many of the effects of neutering a dog too early affect the musculoskeletal system.

In this study on Golden Retrievers, dogs that were neutered early had a much higher risk of many diseases than dogs that were left intact until after a year or dogs that were never neutered at all.

  • In particular, lymphosarcoma was found in almost 10 percent of male Golden Retrievers neutered before 1 year old. This is 3 times more than what was found in intact males.
  • Early neutered males were also diagnosed with hip dysplasia in about 10 percent of the group, which is double the rate for the intact males.
  • The study also found that some diseases, such as cranial cruciate ligament tears, were not present at all in intact males but were found in early neutered males (about 5 percent of the group).

While the Golden Retriever study only looked at one breed, other studies have found similar results.

In addition, there have been some studies that have shown a negative effect on the dog’s behavior and confidence if they are neutered early.

For shy and fearful dogs, removing the testosterone before they have finished going through their fear periods can lead to more fear-related behaviors in the future.

A quick FAQ.

Q: Is it bad to neuter a dog early?

A: There are many health risks related with early neutering and it can be bad for your individual dog.

Q: What is the best age to neuter a male dog?

A: Same as with females. Some resources mention ages between 2 to 8 months of age as being safe, but many studies prove it’s not safe before they’re 1-2 years of age (if it could be considered safe at all).

Q: Does early neutering stunt growth in dogs?

A: Apart from the mentioned health risks, stunted growth is possible and may lead to joint issues or contribute to issues like bone cancer.

Q: Why is my dog more aggressive after being neutered?

A: As outlined above, neutering is a serious procedure and while it can be medically necessary, it’s rarely a behavioral fix.

Q: Does neutering a dog calm them down?

A: Generally speaking, neutering a dog definitely isn’t a sure way to calm your dog down. Most often, training is the way to go but it can possibly help with calming them down (albeit possibly at the cost of their general health).

5 Reasons Why You Should Neuter Your Dog

There are a few reasons why you should neuter your dog so let’s play devil’s advocate.

A word on neutering rescues. It’s sad that shelters and animal rescues have to make neutering mandatory but it makes sense. What we want to absolutely avoid is backyard breeders using rescue dogs.

However, it’d be best to wait until they’re fully grown and establish some system where future dog owners vouch to have the procedure done when the right time comes. Sometimes this is not up to you though.

Similarly, we’re not talking about whether or not you should neuter your dog when it’s absolutely medically necessary as is the case with life-threatening situations.

A false belief that’s sometimes used against neutering is that the dog will lose his masculinity.

Your dog won’t lose his masculinity. But that alone is hardly a reason to decide for neutering.

You may giggle about that one but this is quite a common excuse especially from worried male dog owners.

Oh, while he may not lose the masculinity, it can definitely be that he’ll be picked on after the surgery in the dog park. His own behavior changes and other dogs notice the change too, albeit not assuming that he’s a “wimp”.

1. Offspring control

The last thing you would want from your dog is unwanted offspring.

If you ever compare the neutering costs to caring for pups, paying health check-ups, etc. you may want to go with neutering, especially since it can happen so quickly with females in heat, but do you know what you can do instead?

Look out for your dog.

Don’t let him off-leash if he isn’t reliable with in-heat females around and always be close enough to step in.

Dogs don’t magically tie and start reproducing, the process takes longer than most people think.

It’s a real risk though but I can’t think of a valid reason to let your dog roam and out of your sight anyway. However, if you have a free-ranging dog with plenty of females around, you may have to consider that or changing his lifestyle.

If you’re thinking about accepting breeding as fate, please don’t. It’s not an option. Random breeding most often results in poor temperament and little preparation to raise the puppies.

Breeding two dogs is very costly and needs a lot of time and energy. The female requires veterinary care during pregnancy, after giving birth and the puppies need a lot of attention.

Breeding should only be done by professional breeders with proper breeding programs and plans for socialization, health check-ups, and so on.

2. Stop mounting and roaming

Every male dog’s hormones are strong and if there is a female in heat in their neighborhood, they will smell it from miles away and it can be very stressful for them.

Many male dogs tend to mount anything and everything and it can get really awkward in certain situations.

You might argue that this increases the stress level in the dog and hence neutering is actually good for him.

Well, that’s kinda true.

Most dogs can very well handle that stress though and as long as it doesn’t result in dangerous neurotic behavior, you should be fine.

If you would like to bring home an unspayed female (or get a male while you currently own a female), it might be mandatory to neuter your male dog.

However, it’s beyond me why one would invite that situation into his home unless the adult male was already spayed or you have plans to do so only when the male has reached the proper age.

3. Prevent cancer

In this surgery, the testicles of the male dog will be removed, therefore there is no risk left for testicular cancer or tumors.

The actual treatment for diseases like prostate cancer can include neutering.

Prostate diseases cannot be prevented but the risk after neutering is way lower which also minimizes the risk for infections.

4. Prevent aggression

On one hand, people say it’s not natural to neuter a dog which is definitely right. But on the other hand, not reproducing and going through the cycles time again is also not what nature intended.

“Aggression” is a reason for many owners to get their dog neutered.

Neutered male dogs tend to be less aggressive and less “dominant” (despite it being an outdated term) and show less territorial aggression which could be important if you have other pets or children.

They also tend to get along better with other male dogs. As stated above, it can happen that issues only surface after neutering if there were none before so be careful.

As mentioned, neutering (castration as well as spaying) is not an instant fix for behavioral issues.

5. Pseudopregnancy

If your dog is struggling with pseudopregnancy, other steps can be taken before neutering.

That being said, sometimes the pseudopregnancy symptoms are so strongly expressed and stressful for the dog that your vet may discuss neutering.

Inform yourself about the health risks and evaluate whether or not the stress your dog feels outweighs these risks.

What To Expect After Neutering A Dog?

Immediately after neutering your dog, you’ll need to keep them calm and quiet as they recover from the surgery.

While your dog’s veterinarian will give you exact recovery instructions, the majority of dogs will need 10-14 days of limited activity to allow time for their stitches to heal.

It will also take some time for your dog’s body to get rid of the testosterone that was present when they were intact.

Because of this, you won’t see the full effect on any behavior due to the reduced testosterone levels for up to 6 weeks.

You will also still need to take care of making sure your dog doesn’t breed with any intact females during the 6 weeks after their neuter surgery because they can still remain fertile during this time.

Your dog’s metabolism will also often slow down. This means that while neutering doesn’t make your dog fat by itself, they may need fewer calories.

Do Male Dogs Change Their Behavior After Being Neutered?

Whether or not neutering changes your dog behavior depends on the age at which your dog was neutered as well as your individual dog.

For some dogs, they can be less obsessive about humping or searching for females.

While humping in dogs happens for many reasons, including stress and excitement, intact males are sometimes more persistent about it.

They also will have less of a reason to roam and search for intact females.

Not all dogs forget their desire to hump immediately after neutering, however. Since the presence of testosterone isn’t the only reason dogs hump, you may or may not see a reduction in this behavior.

Neutering before social maturity can lead to increased fears and anxieties in your dog.

If you have a dog prone to anxiety, it’s best to wait until they are mature to neuter them so they can establish a more stable temperament.

While it’s a common thought that neutering decreases the risk of aggression, it can also increase it in some cases.

A more important consideration if you are dealing with an aggression problem is to work with a qualified dog trainer, instead of relying on surgery to stop any problems.

Finally, you may see less urine marking in a neutered male. It’s not guaranteed that neutering will have any effect on urine marking, but it has been noted to decrease in neutered male dogs.

Disclaimer: This blog post does not substitute veterinary attention and does not intend to do so. I am not a veterinarian or pet nutritionist. If your dog shows any sign of illness, call your vet.

About Danielle

Equipped with 5+ years of expertise as a Rottweiler owner, I partner with licensed veterinarians and trainers to share research-backed and actionable advice for you and your furry friend.

Jack Simpson

Thursday 20th of April 2023

Hi Danielle. I have a 20 month old male Mini Aussie named Beau, and this article helped my decision to have him neutered. His nature is active, sweet, and loving, and your article helped me realize he is at a better age to neuter, and another big reason is we're getting a baby female Mini Aussie in a few months, and also will not spade her until she's over a old thanks to this article. I have a 10 1/2 year old male Mini Aussie named Boogie, neutered when he was 4 months, but he can still chase down Beau, and had some of the cleanest 10 year old X-rays our Vet has seen, and he is very active. So I realize that I'm fortunate after neutering Boogie way too early. Thanks for great writing, information, and a good website.


Thursday 27th of April 2023

Hi Jack, I'm glad you found the content helpful. It always pays off to check out the current research to form an opinion, but please also make sure to find a vet you trust and discuss health choices with them. Ultimately, you decide but it's great if you have a vet you can trust.

Glad it went well for your older Aussie! Wish you and your pups the best.


Monday 2nd of January 2023

Hi, I have a 2.5 year old male border collie called Finn. He has an amazing temprament and anybody can approach him, with no aggression at all, including other dogs, but he’s a sniffer - straight for the crotch or bums in other dogs - embarrassing, but really he’s harmless. I don’t want to get him neutered, but wondered if I can buy something to stop him doing the sniffing please?


Monday 2nd of January 2023

Hi Marcia, there's no tool to get your dog to stop sniffing but you may try redirecting your dog and asking a different behavior which is then positively reinforced with a treat, toy, praise, etc.


Wednesday 17th of March 2021

Help my standard poodle's hormones (age 13 mo.) are so annoying. he has congestive heart failure so no surgery is possible. Also your article states his metabolism would slow down, probably not helpful to his heart. What can I do to chill him of this, other than distraction/exercise? ty wendy


Wednesday 17th of March 2021

Hi Wendy, what you can do depends on the exact problem. If I understand correctly, you've planned to neuter your dog because he's too active/overexcited and since that's not an option, due to congestive heart failure, you're seeking alternatives? (As mentioned neutering is not a behavior fix anyway and early neutering can be quite dangerous).

If you're dog needs activity, the only way to get him to calm down is by providing him with exercise.

It's normal for a 13mo dog to be active and you can introduce obedience training to get him to lay down on his place when it's really inconvenient plus house manners in general (when to initiate play and when not to like bedtime for example).

Mental exercise is a really big thing. If your dog like sniffing stuff, get him a snuffle mat or just scatter treats around the house and make it a game. Puzzle games are also great. Anything that tires out the mind, not only the body :).

Cheers, Danielle