Intact male dog and in-heat female dog – Can pheromones help?

Biological Basics

How male dogs perceive oestrus: sense of smell, pheromones, hormones

An intact male dog smells things that we can hardly imagine. Its sense of smell is finely calibrated – and quite particularly the vomeronasal organ (Jacobson’s organ) in the palate, which reacts almost exclusively to pheromones. Female dogs in heat release scent substances via urine, vaginal secretions and skin glands, which are simply irresistible for a male dog.

One of the main actors here is methyl p-hydroxybenzoate – a substance that is excreted during standing heat (oestrus). The message: “I am fertile now.” If a male dog perceives this smell, it often shows the typical flehmen response: It pulls up its upper lip, as if tasting the air. Behind this is not a tic, but function – it directs the scent substances specifically to the vomeronasal organ.

From there, it goes directly into the limbic system, specifically to the amygdala and hypothalamus. These areas control emotions, drives, and hormone release. For the male dog, this means concretely: the sexual drive kicks in – and without conscious filtering.

What happens in the brain and body of the male dog (dopamine, testosterone, cortisol)

With the first sniff, a hormonal cascade starts. Dopamine – known as the neurotransmitter of the reward system – ensures that the dog remains focused and highly motivated to pursue its goal. Testosterone intensifies the reproductive drive, increases aggression towards rival male dogs, and boosts sexual stamina. Cortisol, the stress hormone, rises when the dog is running at peak arousal but never reaches its goal. Restlessness, refusal of food, howling, endless marking – these are typical signs.

These three hormones together create something like a biological tunnel vision. For the male dog, hardly anything else exists in this moment – only the female dog in heat counts.

Why sexual motivation is so strong

This is not disobedience. Not defiance. The extreme motivation of an intact male dog is deeply rooted in evolution. In wolves, in stray dogs – everywhere in free-living canid populations, the rule applies: those who did not reproduce did not pass on their genes. Only animals with sufficiently strong drive survived.

From a biological perspective, the sexual drive is stronger than hunger or play drive. This is not theory, but measurable behaviour. As a dog owner, one thing helps above all: understanding. The dog truly cannot simply act differently in this moment. Training and management can support – the basic need remains.

Pheromones in use

Which pheromones play a role in dogs

In dogs, there are essentially two relevant groups: sex pheromones and calming pheromones. Sex pheromones come mainly from female dogs in heat and attract male dogs – they are the trigger for mating behaviour. Calming pheromones – known as DAP (Dog Appeasing Pheromone) – are produced by female dogs shortly after birth in the area of the milk line. They convey security and calm to puppies.

In everyday training, almost exclusively synthetically produced calming pheromones are used. Products such as Adaptil® are available as collars, diffusers, or sprays – they attempt to synthetically imitate this mother pheromone.

Research: Adaptil and Co.

Several studies have looked at the question of whether synthetic pheromones can really reduce stress and tension in dogs. Mills et al., 2006 showed that DAP measurably reduced stress signals such as panting, barking, and restlessness in animal shelters. Sheppard & Mills, 2003 observed that dogs with noise phobia relaxed significantly better with DAP. And Gaultier et al., 2008 found that puppies in the socialisation phase were calmer and more trainable in training groups with DAP.

For the specific case – male dog in the presence of a female dog in heat – there is, however, no direct clinical study that clearly proves effectiveness. What circulates are deductions from stress research and anxiety applications. This should be known before relying on pheromones as a solution.

Limits and misunderstandings

One thing first: Pheromones are not a sexual brake. A highly motivated male dog will not suddenly become uninterested in a female dog in heat due to DAP. What pheromones can alleviate are secondary stress symptoms – restlessness, panting, excessive howling. But: The effect is not the same for every dog. Some respond well, with others hardly anything is noticeable. The individual differences are considerable.

Pheromones are always only used meaningfully as a supplement to training and management – never as a standalone solution.

Training and management

Desensitisation and counter-conditioning

A male dog that reacts extremely strongly to female dogs in heat needs more than just distance. It also needs training. In desensitisation, the dog is gradually exposed to the smell or presence of a female dog in small doses – always starting at a distance where it remains responsive. Counter-conditioning builds on this: At exactly these moments, positive stimuli come into play – high-quality rewards, play, a calm exercise. In this way, the dog associates the signal from the female dog not only with sexual arousal but also with calm behaviour.

Important: Training must never take place in full heat phase or with direct contact. Otherwise, the risk of frustration or incorrect association is too great.

Signal control and impulse training

Even if a male dog is biologically overwhelmed, practised standard signals help in everyday life. “Look” or “come to me” actively redirects attention. Loose-leash walking under high distraction is practised deliberately with increasing difficulty. Impulse control games such as “Sit – wait – Okay”, mat training, or controlled door opening train the prefrontal cortex – the part of the brain responsible for steering and self-control. A counterweight to the drive-controlled limbic system, so to speak.

Practical tips for everyday life

Alongside training, management measures are crucial to lower the stress level for both dog and owner. Regarding route selection during walks: avoid known hotspots where many female dogs in heat are typically found. Maintain physical distance – no direct dog encounters while in heat. At home, set up a fixed, stimulus-reduced retreat where the dog can truly switch off. And: enrichment alternatives such as scent work, search games or cognitive tasks provide balance when social contacts must be restricted.

Risks and side effects

When training turns into pressure

A common mistake: owners force their male dog to stay calm near a female dog in heat. Punishments, physical pressure or aversive aids – such as a choke chain – do not strengthen control. They create frustration and stress. And from suppressed sexual drive, displacement behaviour can develop: excessive licking, restlessness, and in the worst case aggression towards other dogs or people.

Overwhelm due to training without breaks

Even well-intentioned training can backfire – if the dog is confronted for too long or too intensely. A highly aroused male dog simply cannot learn anymore. The limbic system then blocks cognitive processing. In this state, only management and distance help. Further exercises bring nothing but more stress.

Side effects of aids

Pheromones show no effect in some dogs, and mild sedation in others. Scientifically proven is only a possible stress reduction – drive control is not included. Chemical castration (Suprelorin®) is often used as an alternative to surgical castration. It lowers testosterone but can have unwanted side effects: from weight gain and coat changes to increased anxiety or insecurity tendencies. Phytoproducts such as valerian or passionflower have little evidence – they may act supportively at best, not specifically against sexual drive.

Risk of chronic frustration

A male dog that regularly smells female dogs in heat but never gets relief can become chronically frustrated. Constant howling, marking, sleep problems, permanent restlessness – that is one aspect. The risk of stress-associated diseases – such as skin problems or gastrointestinal irritation – also increases.

FAQ: Intact male dog and female dog in heat

Why does my male dog get so restless around female dogs in heat?

Because he perceives the sex pheromones (e.g. methyl p-hydroxybenzoate) via his extremely sensitive olfactory organ (vomeronasal organ). These scents activate the reward centre in the brain and increase dopamine, testosterone and cortisol – a biologically strong motivation system that is hardly consciously controllable.

Can pheromone products calm my male dog?

To some extent. Synthetic calming pheromones (e.g. DAP) can reduce stress. However, they do not switch off the sexual drive – they act supportively, within the framework of training and management.

Does training help against fixation on female dogs in heat?

Yes. Impulse control exercises, frustration tolerance and clear signals can contribute to the male dog remaining more responsive. Important: train in small steps and consistently avoid overwhelm.

Should intact male dogs be castrated if they suffer greatly?

Castration can bring relief in individual cases, but also carries health risks (e.g. higher cancer risk, orthopaedic problems). Try behaviour therapy, management and possibly chemical castration first.

How long does the critical phase last for a female dog in heat?

The male dog reacts particularly intensely during standing heat – that is approx. 3–5 days. However, many dogs show clear restlessness before and after this period as well.

Why does my male dog not eat when a female dog is in heat?

The reward system is completely oriented towards the sex pheromones. Food loses value during this phase. Additionally, stress hormones such as cortisol further suppress appetite.

Can it become dangerous if two intact male dogs encounter a female dog in heat?

Yes, conflicts are common – both strive for the same resource. Distance management is not an option here, but mandatory.

Are there natural aids against restlessness?

Alongside pheromones, calming routines, scent work, chew items or herbal preparations can have a supportive effect. However, the effect is individual and usually not pronounced.

What should I do if my male dog howls at night because of a female dog in heat?

Block scent sources (close windows, change location), ensure sufficient enrichment during the day and use pheromones if needed. Stay calm – and under no circumstances punish.

Is it unfair to restrain the male dog with pheromones or management?

No. It is not about switching off the drive. It is about reducing stress – so that the dog can relax better and lead a fulfilling life without being permanently overwhelmed.

Conclusion and recommendations

Realistic expectations

An intact male dog will react to female dogs in heat. Always. This is biologically hardwired and cannot be trained away. The goal is therefore not switching off the drive, but rather management that relieves both dog and human equally.

Role of pheromones

Pheromone products – DAP or synthetic analogues of calming pheromones – can act supportively by lowering the general stress level. Neither training nor management replaces them. Their use only makes sense if they are understood as a component in an overall concept – not as a standalone solution.

Recommendations for owners

Decide individually: Not every male dog reacts with the same intensity. Focus on quality over quantity in training – short, positive sessions, no overloading. Distance remains the best immediate measure: avoid female dogs in heat, especially during standing heat. Seek professional advice – consult dog trainers or vets with experience handling intact male dogs. Consider medical options: In cases of severe stress, chemical castration can be discussed – always weighing the pros and cons.

Key message

Pheromones can reduce stress – but they are not a miracle cure. What really matters: understanding owners, clear management, stress-free training and unambiguous rules. Then daily life with an intact male dog becomes more relaxed for everyone involved.