Does Spaying or Neutering a Dog Calm Them Down?

For many dog owners, behavioural issues can be one of the biggest challenges of pet ownership. From jumping up at visitors to excessive barking or mounting, it’s common to wonder whether these behaviours are linked to hormones — and, more importantly, whether spaying or neutering can help calm them down.

This question — “Does spaying or neutering a dog calm them down?” — doesn’t have a simple yes or no answer. The impact of these procedures on behaviour depends on several factors including your dog’s age, breed, temperament, and environment. However, understanding how spaying and neutering affect your dog’s hormones and development can help you make an informed decision.

In this article, we’ll look at what these procedures involve, how they influence behaviour, the potential benefits and drawbacks, and what to expect if you decide to go ahead.

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What Does Spaying or Neutering Mean?

Before discussing behavioural changes, it’s important to understand what these procedures actually involve.

Spaying (for females)

Spaying is the surgical removal of a female dog’s ovaries and usually her uterus. This prevents her from going into heat and eliminates the possibility of pregnancy. The procedure is typically done under general anaesthetic and is considered routine by most vets.

Neutering (for males)

Neutering, or castration, involves removing the testicles of a male dog. Like spaying, it’s performed under general anaesthetic. This stops the production of sperm and drastically reduces levels of the male sex hormone testosterone.

Both procedures are forms of sterilisation, but they also bring hormonal and behavioural changes that can affect your dog’s temperament and energy levels.

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Why People Think Spaying or Neutering Calms Dogs Down

Many dog owners report that their pets seem calmer and easier to manage after being spayed or neutered. There’s some truth to this — but it’s important to understand why.

Hormones, particularly testosterone and oestrogen, play a key role in influencing behaviour. When a dog is intact (not neutered or spayed), these hormones drive certain instinctive behaviours, such as:

• Roaming or escaping to find a mate

• Mounting or humping other dogs, people, or objects

• Territorial marking with urine

• Aggression towards other dogs (especially same-sex aggression)

• Restlessness or anxiety during heat cycles (in females)

When these hormones are reduced or eliminated through spaying or neutering, these instinctive drives can lessen over time. As a result, many owners notice their dogs are more relaxed and less reactive.

However, the procedures don’t automatically change a dog’s personality or fix all behavioural issues. Some behaviours are learned, not hormone-driven — and these require training and consistency, not surgery.

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How Hormones Affect Dog Behaviour

In Male Dogs

Testosterone is responsible for much of a male dog’s sexually driven behaviour. High levels of testosterone can make dogs more:

• Dominant or territorial

• Prone to roaming

• Likely to mount other dogs or objects

• Reactive or aggressive, especially around other unneutered males

After neutering, testosterone levels drop significantly — though not to zero, as small amounts are still produced by the adrenal glands. This hormonal change can reduce or eliminate these behaviours, but it can take a few weeks or months for hormone levels to stabilise.

However, neutering doesn’t necessarily make a dog less playful or affectionate. In fact, many owners report that their dogs become more focused and responsive once hormonal distractions subside.

In Female Dogs

Oestrogen and progesterone affect a female dog’s behaviour during her heat cycle. When she’s in season, she may:

• Become more restless or vocal

• Try to escape to find a mate

• Attract male dogs from the area

• Experience changes in appetite or mood

• Display nesting or mothering behaviours

Spaying stops the heat cycle entirely, which can significantly reduce these fluctuations in behaviour. It also removes the risk of false pregnancies, where a dog shows signs of pregnancy without being pregnant, which can cause anxiety or aggression.

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When Spaying or Neutering May Calm a Dog Down

While every dog is different, here are some cases where the procedures are most likely to help:

1. Roaming and Wandering

Unneutered males can travel long distances if they pick up the scent of a female in heat. Neutering typically reduces this drive, helping dogs stay closer to home and making them less likely to run away.

2. Marking and Territory Behaviour

Male dogs often mark their territory by urinating on objects, especially when other dogs are nearby. Neutering can reduce or eliminate this behaviour in most cases, though it’s best addressed early before it becomes a habit.

3. Aggression Related to Mating or Hormones

Some dogs, particularly males, show aggression towards other dogs or people when competing for mates. By reducing testosterone, neutering can lower these aggressive tendencies — though it won’t fix aggression caused by fear, poor socialisation, or trauma.

4. Restlessness or Anxiety During Heat Cycles

Female dogs often show restlessness or agitation during their heat cycles. Spaying removes these cycles entirely, which can make a female dog calmer and more stable in temperament year-round.

5. Mounting and Sexual Behaviour

Neutering reduces sexual motivation and behaviour, including excessive mounting. However, some dogs continue to mount due to excitement or dominance, which must be addressed through training.

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When Spaying or Neutering Might Not Change Behaviour

It’s a common misconception that neutering or spaying is a quick fix for behavioural problems. While it can help reduce hormonally driven behaviours, it won’t automatically make your dog calm or obedient.

Here are situations where you might not see a noticeable difference:

1. Learned or Reinforced Behaviour

If a behaviour (like jumping up or barking) has been learned and reinforced over time, removing hormones won’t change it. Training, routine, and structure are still key to improving these behaviours.

2. Anxiety or Fear-Based Issues

Neutering doesn’t treat anxiety, fear, or reactivity. In some cases, if performed too early, it can even worsen these issues because hormones play a role in emotional development.

3. Overexcitement or Lack of Exercise

A high-energy dog will still need regular exercise, mental stimulation, and boundaries. Surgery won’t turn a hyperactive dog into a calm one overnight.

4. Age and Timing

The timing of spaying or neutering matters. If done too young, it can interfere with physical and mental development. If done too late, certain behaviours may already be ingrained.

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What Age Should You Spay or Neuter Your Dog?

Veterinarians generally recommend waiting until a dog has reached physical maturity before performing the procedure, though this depends on breed and size.

• Small breeds often reach maturity around 6–9 months.

• Medium breeds mature around 9–12 months.

• Large or giant breeds may benefit from waiting until 12–18 months or later.

Early neutering can reduce some unwanted behaviours sooner, but delaying it can allow bones and muscles to develop fully, potentially reducing the risk of joint problems in large breeds.

Always consult your vet for advice tailored to your dog’s breed, size, and lifestyle.

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Benefits Beyond Behaviour

Even if the behavioural benefits vary, there are clear health and practical advantages to spaying or neutering your dog.

Health Benefits

• Prevents certain cancers: Neutering removes the risk of testicular cancer and reduces prostate disease in males. Spaying eliminates the risk of uterine infections (pyometra) and significantly lowers the risk of mammary (breast) cancer in females.

• Avoids pregnancy complications: Spaying removes the risk of unwanted litters and potential birthing complications.

• Reduces hormone-driven illnesses: Both procedures can help prevent hormone-related issues, such as false pregnancies or testicular enlargement.

Practical Benefits

• No more heat cycles or bleeding around the house

• Fewer dogs roaming and causing problems in neighbourhoods

• Reduced risk of accidental litters and abandoned puppies

• Fewer hormone-related behavioural issues to manage

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Possible Drawbacks or Side Effects

While there are many benefits, it’s also important to be aware of potential drawbacks.

1. Weight Gain

Spayed and neutered dogs tend to gain weight more easily due to lower metabolism. This can be managed with proper diet and regular exercise.

2. Risk of Early Neutering

Neutering too early may slightly increase the risk of joint disorders, particularly in large breeds, as growth plates close later. Always discuss timing with your vet.

3. Behavioural Shifts

While some dogs become calmer, others might become slightly more fearful or anxious if neutered before full maturity. Hormones play a role in confidence and emotional stability.

4. Irreversibility

Once done, the surgery can’t be reversed. It’s a lifelong decision, so it’s best made after careful consideration and veterinary advice.

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How to Support Behaviour After Spaying or Neutering

If your goal is to help your dog become calmer, surgery should be one part of a broader approach to behaviour and training. Here’s how to support your dog post-surgery:

1. Give them time to recover.
   After the operation, your dog will need rest and restricted activity for around 10–14 days. Avoid walks or play that could strain stitches.

2. Reinforce calm behaviour.
   Reward your dog when they are calm or relaxed. Use positive reinforcement rather than punishment to encourage the behaviour you want.

3. Provide structure and exercise.
   Regular walks, mental stimulation, and routines help reduce anxiety and restlessness.

4. Be patient.
   Hormone levels take time to adjust — it may take several weeks or even months to notice behavioural changes.

5. Consider professional training.
   If unwanted behaviours continue, a qualified trainer or behaviourist can help identify underlying causes and develop a plan.

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Myths About Spaying and Neutering

Let’s clear up a few common misconceptions:

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Final Thoughts: Does It Really Calm Them Down?

Spaying or neutering can help calm your dog down, particularly if their behaviour is driven by hormones — such as roaming, marking, or sexual behaviour. However, it’s not a guaranteed solution for hyperactivity, aggression, or anxiety.

The best approach combines good timing (based on your vet’s advice), consistent training, mental stimulation, and a balanced lifestyle. Think of the surgery as one part of a long-term plan for your dog’s wellbeing, not a magic fix.

When done thoughtfully, spaying or neutering can lead to a happier, healthier, and often more relaxed companion — both for your dog and for you.

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Key Takeaways

• Spaying and neutering reduce hormone-driven behaviours like marking, roaming, and mounting.

• They do not automatically “calm” every dog — training and structure are still essential.

• The timing of the procedure matters, especially for large breeds.

• Health benefits include reduced risk of cancers and infections.

• Always consult your vet for breed-specific advice before making a decision.