CBD products for dogs have exploded in popularity in recent years, and the marketing has been bold: stress relief, pain management, calmer behaviour and better sleep have all been promised. Yet the science has lagged far behind the sales pitch for CBD in dogs, until now. A major new study drawing on data from over 47,000 dogs has produced the most detailed picture yet of how CBD is used by pet owners in the United States and the effects it appears to have. The results are nuanced, and every dog owner considering CBD should know them.
The largest study of its kind
The research was published in late 2025 and draws on data from the Dog Aging Project – a long-running community science initiative in which owners provide yearly updates on their pets’ diet, lifestyle, health, and living conditions. A total of 47,355 dogs were included, with information collected through annual surveys between 2019 and 2023.
Owners reported how often their dogs consumed CBD or hemp products, whether as a daily supplement or less frequently. This gave researchers something genuinely rare in veterinary science: a large, long-term, real-world dataset about a supplement that has largely evaded formal clinical scrutiny.
Who is actually using CBD?
One of the most revealing findings is the profile of dogs whose owners turn to CBD. The supplement was most commonly used in older pets dealing with chronic health issues like dogs with arthritis, anxiety disorders, or other age-related conditions. This aligns with the anecdotal experience of many owners, who tend to explore CBD when conventional treatments have fallen short or when they are looking for a gentler complementary option.
The surprising behaviour shift
On the question of behaviour, the study produced a striking finding. Dogs that received CBD over extended periods were described by their owners as having lower-than-average aggression levels compared to dogs with no CBD use. This pattern was consistent enough to suggest that CBD could play a meaningful role in reducing aggressive behaviours.
However, and this is an important caveat, other anxious or agitated behaviours did not show the same improvement. Dogs using CBD were not reported as being generally calmer or less fearful. Only aggression appeared to be affected. The researchers themselves noted the puzzle: “Most canine aggression is related to underlying stress or anxiety – a fight or flight response that kicks in. It is unclear why only aggression but not other types of anxious or agitated behaviors seemed to be improved with CBD treatment.”
What we still don’t know
The study is observational, which means it tracks patterns rather than establishing direct cause and effect. The researchers did not explore the biological reasons behind the behavioural shifts, and they acknowledge that controlled clinical trials will be necessary to confirm CBD’s potential as a therapy for canine aggression. It is also possible that owners who choose CBD are, for other reasons, more attentive to their dogs’ welfare, which could itself influence behaviour outcomes.
Safety data in the study was also limited. While CBD is generally considered well-tolerated in dogs at moderate doses, veterinary guidance varies, and the long-term effects of regular use are still not well understood.
What should owners take away?
The evidence suggests that CBD may have a real, measurable effect on aggression in dogs, but it is not a cure-all for anxiety, and it is certainly not a substitute for professional behavioural assessment or veterinary care. If your dog is displaying aggression, the root cause matters: pain, fear, resource guarding, and social stress all require different approaches, and CBD is unlikely to address these underlying issues on its own.
If you are considering CBD for your dog, discuss it with your vet first. Ask about dosing, product quality (the CBD market is poorly regulated), and how it fits alongside any existing treatment plan.
Source: Dog Aging Project, published in Frontiers, November 2025. Co-authored by Dr. Julia Albright, University of Tennessee College of Veterinary Medicine.
