Across nearly 50,000 American dogs, a subtle CBD story is taking shape, one woven from small daily choices owners make and the gradual behavioral shifts that follow.
The latest analysis from the Dog Aging Project, drawing on 47,355 dogs nationwide, traces who is receiving cannabidiol or hemp supplements and how those dogs change over time. Older animals and those living with chronic illness are far more likely to get CBD, and in a longitudinal slice of the dataset, dogs receiving these products for years showed something unexpected. They began as the more reactive, more aggressive animals in the population, yet their aggression softened as time passed, eventually becoming milder than average. The work appears in Frontiers in Veterinary Science.
Age, Ailments, And The Politics Of Place
Since the 2018 Farm Bill legalized hemp-derived CBD, the product has flooded into human wellness markets promising relief for pain, anxiety, sleep difficulties, and inflammation. That cultural wave extends to pet owners. Of the dogs surveyed, 3,470, or 7.3 percent, had received CBD at some point, and 2,759 were daily users. These long term users were older by roughly three years compared to dogs that had never received CBD, suggesting that many owners reach for supplements as animals age into arthritis, cognitive decline, cancer, or chronic discomfort.
Patterns of use mirrored human policy. CBD was more common in states where medical cannabis is legal, pointing to a straightforward idea: people accustomed to cannabis in their own lives may be more open to offering related products to their pets. Male dogs were somewhat more likely to receive CBD, though the reason for this gap remains unclear. Breed, weight, sterilization status, and activity level did not show meaningful differences between CBD users and nonusers.
Health status provided a sharper divide. Dogs with dementia had the highest CBD prevalence at 18.2 percent. Osteoarthritis followed at 12.5 percent, and cancer at 10 percent. Adjusting for dog demographics and owner income, education, and age, seven conditions still remained significantly associated with CBD use: dementia, osteoarthritis, epilepsy or seizures, hip dysplasia, cancer, chronic diarrhea, and broader gastrointestinal disorders. These reflect a mix of painful conditions, neurodegenerative disease, and perceived inflammation, echoing the conditions for which humans often experiment with CBD themselves.
“Behaviorally, dogs given CBD products for multiple years are initially more aggressive compared to dogs not receiving those products, but their aggression becomes less intense over time,” said senior author Dr Maxwell Leung, an assistant professor and the director of Cannabis Analytics, Safety and Health Initiative at Arizona State University.
When Aggression Slips Instead Of Settling In
To understand how behavior shifted, the team studied 17,730 dogs with at least two yearly surveys. Among them, 331 dogs had consistent CBD use and 17,399 had none. Owners filled out a modified Canine Behavioral Assessment and Research Questionnaire, scoring aggression, fear, and agitation on a five point scale, year after year. Because each dog effectively served as its own baseline, the researchers could track changes tied to aging and compare slopes between CBD users and nonusers.
The pattern was striking. Dogs on CBD began with more intense reactions to unfamiliar situations and other animals, and higher aggression generally. Over time, these scores declined at a noticeably steeper rate than those of dogs who never received supplements. Eventually, long term CBD users landed below average in their aggression scores. For other behaviors, including fear and general agitation, the teams found no reliable differences between groups. Physical activity was also similar regardless of CBD use.
“This long-term behavioral change highlights the potential of CBD as a therapy for canine behavioral issues,” added co-author Dr Julia Albright, an associate professor at the College of Veterinary Medicine at the University of Tennessee.
A Mirror Of Human Hopes, And The Questions Ahead
The authors are careful to note that this is observational research. Every data point comes from an owner report, not a veterinary clinic or controlled trial. Some owners may have overstated aggression or forgotten to log CBD use. The cohort itself skews older and wealthier than the national dog owning population, which shapes what kinds of supplements people can afford and how they interpret their pet’s needs. And without dosage information or standardized formulations, it is impossible to tease apart what CBD product or amount might matter.
There is also the question of motives. Many dogs receiving CBD started out more aggressive, which suggests owners may have turned to supplements in response to already challenging behavior. Training, other medications, or broader changes at home may have also contributed to improvements. The study cannot separate these threads.
But taken as a whole, the findings capture something real happening in American households. As CBD becomes normalized in human health and wellness, owners are extending the same logic to aging, uncomfortable, or reactive dogs. They are doing so in the absence of clear veterinary guidelines, relying instead on intuition, anecdote, and hope.
The next steps will need more precision. Placebo controlled trials that measure cortisol, track activity continuously, and document product composition could help clarify whether CBD is damping aggression directly, easing underlying pain, or simply coinciding with other interventions. For now, the population scale data suggest a simple truth: many people believe CBD helps their dogs feel and behave better, and in at least one measurable way, those dogs appear to be changing in kind.
Journal: Frontiers in Veterinary Science. DOI: 10.3389/fvets.2025.1666663.
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