31/05/2026
What does the science actually say about chemical castration and behaviour?
As behaviourists, we often work with clients who believe castration will resolve a specific behaviour problem. In practice, disentangling the myths around this is a regular part of the job.
When a client is fixed on exploring castration as an option, one approach is to suggest they first discuss chemical castration with their vet. If it proves ineffective or makes things worse the effects are at least reversible.
A recent study by Roulaux and van Herwijnen (2025) offers some interesting insight into exactly this.
The highest-scoring reason owners gave for chemical castration was to test what surgical castration might do to behaviour. Chemical castration was most commonly recommended by vets, but also in some cases by trainers or behaviourists and owners who received the recommendation from both reported the strongest positive outcomes.
Interestingly, many owners chose to keep their dog intact after chemical castration which may suggest that the reversible nature of the procedure proved genuinely useful in assessing its effects.
It is worth noting that this study relies on owner-reported outcomes, and perceptions of what counts as a positive or negative effect are inherently subjective. Even so, it offers a useful window into how owners think and make decisions around castration.
Written by Daniel Shaw
Brain and Behaviour Academy
Roulaux, P. E., & van Herwijnen, I. R. (2025). Chemical castration of male dogs: Owner-reported effects on behaviour and health, reasons for chemical castration, and similarities with subsequent surgical castration. Journal of Veterinary Behaviour.
