The Largest Dog CBD Study Yet: What 47,000 Dogs Tell Us About Aggression

The Largest Study Yet on CBD and Dog Behavior — and Why the Details Matter

If you've ever wondered whether the CBD you give your dog actually changes anything, a new study is the closest science has come to an answer at scale. Researchers analyzed data from 47,355 dogs and found that dogs receiving CBD over the long term showed lower aggression intensity over time compared to non-users. That's a genuinely interesting finding — and the honest, useful thing we can do for you as a pet owner is explain exactly how much weight it can carry.

What the Researchers Actually Found

The analysis, published in Frontiers in Veterinary Science, drew on the Dog Aging Project — a long-running study following tens of thousands of U.S. dogs. Dr. Maxwell Leung of Arizona State University and Dr. Julia Albright of the University of Tennessee College of Veterinary Medicine examined CBD use, health, and behavior data collected annually from 2019 through 2023.

Three findings stand out for pet owners:

• About 7.3% of dogs in the dataset were given CBD or hemp products — with higher use in states where cannabis is legal.
• Dogs on long-term CBD showed reduced aggression intensity over time, compared with dogs who didn't receive it.
• Other anxious behaviors — like general agitation — did not show the same improvement.

That last point is what makes the study honest rather than hype. As Dr. Albright put it, “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.” When researchers flag their own puzzle, that's a sign of careful science.

The Big Caveats (Because They Change What This Means for You)

The researchers were clear about the limits, and so are we:

• No dosing or product data. The study didn't capture how much CBD dogs got, what form, or from which brands — so it can't tell you what to give or how much.
• Owner-reported behavior. Behavior was reported by owners, which can introduce bias in either direction.
• Association, not proof. A controlled trial — where dogs are randomly assigned CBD or a placebo — is what's needed to confirm cause and effect.

None of that makes the finding worthless. A 47,000-dog signal is exactly the kind of result that should send researchers into the lab to run the controlled trials that come next.

Where This Sits Next to Stronger Evidence

Here's the honest picture of where dog CBD research stands. Most of what you'll read online sits near the bottom of the evidence ladder — single testimonials and anecdotes (Level 8). This new study is a meaningful step up to Level 4. And a smaller number of controlled clinical trials — higher still, at Level 2–3 — have looked at CBD for specific measures like joint comfort in dogs.

That's the ladder HempMy Pet holds itself to. Our own products were studied in a 90-day clinical trial of 30 dogs overseen by Dr. Robin Downing, DVM, with researchers at Colorado State University, looking at measures of joint comfort and owner-reported quality of life — a prospective clinical study (Level 3), a rung above the observational data above. We think you deserve to know where every claim sits, including ours. You can read the details and lab documentation on our clinical trials page and published certificates of analysis.

What a Pet Owner Should Take Away

If you already give your dog a quality CBD product for general calm and wellness, this study is a reason for cautious encouragement, not a green light to expect a personality change. If you're considering it, the smart path is the same as always: talk with your veterinarian, choose a product with published third-party lab results, and watch your own dog's response over time. The science is moving in an interesting direction — and we'll keep reporting it as honestly as it comes.

Frequently Asked Questions

Does this study prove CBD reduces aggression in dogs?

No. It's a large observational study of 47,355 dogs that found an association between long-term CBD use and lower aggression intensity. Observational studies can't prove cause and effect — that requires a controlled trial where dogs are randomly assigned CBD or a placebo. The finding is a strong reason to run those trials, not a substitute for them.

How many dogs were in the study?

47,355 dogs from the Dog Aging Project, with behavior and health data collected annually from 2019 to 2023 — making it the largest analysis of CBD and dog behavior to date.

Did the study say how much CBD to give a dog?

No. The researchers specifically noted they didn't have data on dosage, product formulation, or administration method. For dosing, work with your veterinarian and follow the guidance on a lab-tested product.

Why did aggression improve but not other anxious behaviors?

The researchers don't know, and they said so. Dr. Julia Albright noted it's unclear why aggression specifically — but not general agitation — appeared to improve, since both are usually tied to stress. It's one of the open questions the study leaves for future research.