How Long After Neutering Dog Is Testosterone Gone?

Zack Keithy, our author, is a certified veterinarian technician (UC Blue Ash) for over 6 years (contact him here). The articles written here are based on his expertise and experience, combined with a review by our expert vet reviewers including Dr M. Tarantino. Learn more about us here.

Remember that bittersweet day when you dropped off your beloved pup at the vet’s for “the snip”? You know, neutering, the ultimate doggy dude makeover?

You may be wondering, “How long after neutering dog is testosterone gone?”

Well, it’s not an answer that can be given directly, but I’m here to guide you through this hormone rollercoaster.

In this post, let’s learn a bit more about this hormone, how it affects our dogs, and what changes you can expect to see moving forward.

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What Dog Bodily Functions Does Testosterone Affect?

What Dog Bodily Functions Does Testosterone Affect?

Sexual behavior

Testosterone affects your dog’s sexual behavior in a way that makes your dog more active and persistent to mate.

If you notice your dog trying to hump another dog or even an inanimate object, it’s surely due to his testosterone.

Testosterone drives your doggy to mount a female dog too whenever he senses that the female dog is in heat.

Dog’s aggression or temperament

I know you’ve already noticed your male dog becoming more aggressive when he hits adulthood.

Your dog’s testosterone isn’t only pushing your dog to engage in mating. 

It also activates a certain area in your dog’s brain, which makes him more competitive towards other male dogs.

Your dog’s testosterone makes him think that he competes with another male dog to mate with a female dog.

Marking behaviors

The high levels of testosterone your male dog has increases the production of his pheromones.

You gotta know that a pheromone is a chemical that your dog releases to communicate with other dogs and mark his territory.

When the production of pheromones increases, your dog will also increase his marking behaviors.

He’ll be able to release more pheromones thanks to his testosterone that’s why he can mark his territory more frequently.

How Long Does It Take for Testosterone to Leave a Dog’s System?

How Long Does It Take for Testosterone to Leave a Dog's System

If you had your dog neutered, it’s necessary to know that his testosterone won’t leave his system right away.

Neutering’s effects on a dog’s system aren’t immediately observed, so it’s only usual for the testosterone to leave the system several weeks after, most typically 4-6 weeks.

While the testosterone is slowly leaving your dog’s body, you’ll observe that he’ll be less energetic.

He won’t be as playful or affectionate as usual.

However, your dog will go back to his normal mood a few weeks after being neutered.

When your dog gets back to his normal behavior, it’s understandable that the testosterone has already left his system. 

I need to emphasize that your dog’s testosterone doesn’t completely leave his system, that’s why some of his masculine behavior will still be observed.

These masculine behaviors won’t be as frequent and pronounced though. They’ll look more like just the remnants of the masculinity your dog had.

Doggy says, you might wanna read this too: Can you board a dog in heat?

What Changes You Can Expect in Your Dog After Testosterone Leaves His System

You should expect several changes in your dog after testosterone leaves his system.

These changes will mostly be observed in terms of their sexual and aggressive behaviors.

  1. Decrease in sexual engagement.
  2. Decrease in finding potential mates.
  3. Decline in urine marking frequency.
  4. Less aggression towards male dogs.

How Does Neutering Affect Testosterone?

Neutering means that your dog’s testicles will be surgically removed.

Testicles, if you haven’t heard them before, are the main source of your dog’s testosterone.

They are located in your dog’s scrotum, and they produce not just testosterone but also sperm.

Once these testicles are gone after neutering, your dog will have so little amount of testosterone in his system. 

Some dog owners opt for neutering when they wanna lessen the testosterone of their dogs as they’ll be less aggressive to mate.

How Does Testosterone Impact My Dog’s Behavior?

Testosterone impacts your dog’s behavior when it comes to roaming, mounting, and aggression.

When your dog is unneutered, he’s more sexually active so his tendency to roam around to look for potential mates is more frequent.

Because your dog wants to mate, he’ll be mounting and humping other dogs more often.

This may be embarrassing but testosterone makes your dog mount people as well when he can’t find any female dog.

The hormone also makes male dogs more aggressive too.

They tend to get into fights with other dogs, especially if there are more male dogs compared to female dogs in the area.

Testosterone pushes your male dog to constantly get out of your house to find a mate.

You and I both know the danger of roaming the streets though.

Your dog might be hit by a passing vehicle while he’s roaming the streets, or get into a serious brawl with other male dogs.

Will neutering my dog calm it down?

Neutering reduces your dog’s sexual motivation, hence calming him down in that sense.

Since your dog will have lesser sexual motivation after neutering, he’ll be less excited to roam and mount other dogs.

Of course, your dog will still want to mate from time to time but he won’t be as aggressive.

You’ll also observe a decrease in fight engagement with other male dogs since your dog won’t any longer feel in competition to mate.

Neutering doesn’t totally eliminate a dog’s sex drive, but it’s ideal to keep your doggy calmer and more friendly.

What You Should Consider When Deciding to Neuter Your Dog

I’ve actually written quite a fair bit about the pros and cons of neutering breeds like huskies, boxers, and more. Be sure to check them out if you’re keen to learn more.


Your dog’s age should be considered when you wanna neuter your dog.

Most dog owners are advised to neuter their dogs at 6 months old, but this is not 100% accurate information. I recommend you check out this study and talk to your vet first before making that decision.

The thing is, most dogs exhibit active sexual behavior around this time, and to lessen their aggression caused by this, dog owners opt to neuter.

The problem is, fixing your dog too early can lead to long term problems down the line, so be sure to check this out properly before doing so.

Dog breeds

There are dog breeds that are more prone to aggression, so you’ll also need to consider the breed of the dog when neutering.

Many studies prove that American Pit Bull Terriers, Akita, and Doberman Pinschers are among dog breeds that exhibit aggression especially when it comes to mating.

Hence, you’ll also need to assess whether or not the breed your dog has is more prone to aggressive behavior.

As I’ve said before, neutering can make dogs calmer, so particular breeds may need it to be less aggressive.

Dog owners preference

Some dog owners prefer having lesser pups to take care of.

If you’re the kind of fur parent who doesn’t wanna get your hands full with pup-related responsibility, you may opt for neutering.

Neutering will stop your male dog from siring puppies. 

It’s a wise decision to make to cut expenses and to give more attention to the dogs you already have.

Myths Often Associated With Neutering a Dog

Neutering a dog is expensive

There are many animal organizations out there that offer free neutering from time to time. 

Plus, having more puppies to take care of is more expensive than one-time neutering.

You’ll have to spend more on food, vitamins, and vet visits when your dog sire more litter, won’t you?

So I think we should agree that neutering a dog makes your duty as a dog owner less expensive.

Neutered dogs will be overweight

The only thing that will make your dog overweight is overfeeding them, neutering him won’t cause that.

In fact, neutered dogs don’t have to be fed with a full bowl all the time.

Neutered dogs can be fed with only 3/4 of the servings they once have been fed with.

Neutered dogs will be sad over the loss of their testicles

To assume that dogs become sad because they can no longer reproduce is absolutely false.

Dogs can’t register the fact that they have been neutered and that they can no longer sire puppies.

Dog reproduction is only by instinct, it doesn’t have any personal or emotional reason behind that.

A dog is purely nonchalant whether or not he reproduced a litter of puppies.

How to Care for Your Dog After Neutering?

How to Care for Your Dog After Neutering

Care upon coming back home

Upon coming home after neutering your dog, your dog will be less energetic.

He’ll even appear stressed and not in the mood to interact. In fact, it’s not uncommon to see a dog keep sitting after getting neutered or spayed.

Place him in a quiet and dim-lit room where his crate or comfortable bed is set up so as to not stimulate it unnecessarily. It wouldn’t be good to have a dog jump after being fixed.

The anesthesia that’s making him lethargic and out of focus will eventually wear off after 24 hours.

Feed him his normal servings as per schedule, but don’t be surprised if he has no appetite.

The surgery can be so uncomfortable and stressful for your dog that he’ll have no appetite to eat.

2 weeks aftercare 

Your dog shouldn’t engage in a lot of physical activities within 2 weeks after being neutered.

Physical activities like playing, running, and jumping can cause swelling around your dog’s wound, which can lead to infection.

You shouldn’t also wet the incision, so when can you shower or groom your dog after neutering?

Again, give it at least 2 weeks.

It’s also important to prevent your dog from scratching or licking his incision as it can irritate and may open the wound.

You can put an E-collar to make sure your dog can’t reach to lick his incision.

During this time, it might also have problems holding its pee, so a dog diaper after neutering might be useful too.

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Frequently Asked Questions (FAQs)

Do neutered dogs have low testosterone?

Yes, neutered dogs have low testosterone because their testicles are removed in the process of such surgery. 

Why is my dog more aggressive after being neutered?

Since your dog has a lesser amount of testosterone in his system after neutering, he’ll experience an imbalance in hormones. This is the reason why he might be more aggressive after neutering. However, this is only temporary, and 2 weeks later he’ll return to his normal behavior.

At what age should I neuter my dog?

There is not fixed age as to when to neuter a dog. Different breeds have different optimal times to be fixed, so a check with your vet and doing sufficient research is your best resource for understanding this.

Can neutered dogs still mate?

Neuter dogs can still mate since it is only the testicles being removed, not his penis. However, mating will no longer result in a litter of puppies.

In Conclusion: How Long After Neutering Dog Is Testosterone Gone?

As you now know, it takes approximately 4-6 weeks for a dog’s testosterone levels to drop post-neutering.

However, remember that every dog is unique and different, so don’t take that number as something absolute.

Rest assured though that this procedure benefits your furry friend’s health and behavior, making your bond even stronger.

Happy tails to you and your pup!

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Zack Keithy
Zack Keithy

Hey, I'm Zack, the Chief Editor here. I was formerly a Certified Veterinary Technician (CVT) for a good 6 years before moving on to greener pastures. Right now, I am still heavily involved in dog parenting duties, and it is my desire to share all our knowledge with fellow dog owners out there! Connect with me on LinkedIn, or read more about Canine Care Central!

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