This is a question the I get A LOT in appointments and I love that folks are asking it. There is one thing I should say before I go any further - anytime you want to give your dog any supplement you should ALWAYS check with a veterinarian to make sure it makes sense with your pet’s medical or behavior history and any current medications.

What does the research say?

Unfortunately, it is limited! While more studies have been done since I first started getting this question, there is still a lot we don’t know.

My Overview: Well-sourced and -produced CBD oil seems to be relatively safe and low risk short-term. But there is A LOT we don’t know about possible long-term effects, dosing for individuals or breeds, interactions with many health conditions and medicines, and actual effects on behavior or anxiety.

Pain Reduction

There are multiple studies that suggest CBD oil can reduce pain and increase activity in dogs suffering from osteoarthritis and inflammation (Brioschi 2020; Gamble 2018; Gugliandolo 2021; Yu 2021).

That sounds pretty promising, right? Yeah, that is awesome! But all of those studies also call for more research on long-term effects and appropriate dosing. We don’t know enough about how CBD oil might effect dogs and cats long-term, especially internally.

For cats - there are no studies about how CBD effects pain or inflammation in cats that I could find.

Long Term Use

I do appreciate a couple of studies that specifically looked at long-term administration and addressed some of the liver concerns raised by earlier studies. One study (Bradley 2022) suggested that healthy dogs given CBD oil over a 6-month period had normal livers and that increased levels of one chemical that can sometimes indicate liver damage was in fact coming from somewhere else in the body. This study ALSO noted how individual dogs and possibly different breeds might retain or build-up CBD and byproducts very differently. We don’t know how a build-up of CBD or CBD-related chemicals may effect dogs longer than about 6 months. (Bradley 2022; McGrath 2018)

In cats specifically, it also seems to be relatively safe short term but with some more concerning possible long-term effects that are even less studied than in dogs (Deabold 2019; Kulpa 2021; Wang 2022; Yu 2021).

Side Effects

“Safe” short-term means that side effects are considered mild or at least not dangerous. Many studies report gastrointestinal side effects and specifically diarrhea. If your cat or dog already has a sensitive stomach or gastrointestinal issues definitely keep this in mind. (Bradley 2022; Deabold 2019; McGrath 2018; Kulpa 2021).

Some studies do suggest that the exact type or quality/purity of CBD product can effect side effects as well as absorption (Bartner 2018; Kulpa 2021; Wang 2022).

All of the dogs and cats in studies are considered “healthy” animals and any animal with regular health issues would have been excluded from research - except for the studies specifically looking at particular issues like osteoarthritis or seizures.

Anxiety and Behavior

Studies on CBD’s actual effects on anxiety and behavior are even more limited than studies on the internal effects.

There is a single study I could find (Corsetti 2021) that suggested that CBD oil might reduce aggression towards humans in shelter dogs - but there is also a possibility that it was simply change over time since the difference was not significantly different from the control group of shelter dogs. (I also super appreciate any study or remedy that may help shelter dogs get any relief or relaxation.)

I found one study about CBD oil and sound sensitivity (Morris 2020); but unfortunately the results suggested that CBD oil did not give sound-sensitive dogs any additional anxiety relief with their trigger sounds.

The only other studies I could find on CBD and anxiety relied on owner opinions which is a tricky thing and many seemed to be funded by treat companies already selling CBD treats. Some people did feel like their dogs were more mellow, but there could be a lot of bias in these studies.

Talk to Your Vet! Consider Well-Proven, Well-Studied Supplements or Medications

Your vet may or may not recommend CBD oil. My 2 cents is that I don’t feel like I know enough to be comfortable giving CBD to my dog long term/regularly even when I do know the source and processing. Many commercial treats do not say where their CBD is from, how it is processed, or sometimes even the dosage of each treat.

These are the supplements and over-the-counter calming aids that I am familiar with, I know are well studied, and have been recommended by vets and vet behaviorists:

• L-Theanine - specificially Virbac Anxitane, VetriScience Composure, and NutraMax Solliquin

• Zylkene

• Purina Calming Care Probiotics

• DAP (dog appeasing phermone) - diffusers, collars, and sprays. I personally use an Adaptil diffuser.

• Thunder vests for some dogs - it depends! If your dog is skin sensitive or generally hates wearing clothes this probably isn’t the one for you.

But again - ask a vet or veterinay behaviorist. Sometimes this discussion also leads into pros/cons/thoughts about medication versus over-the-counter options AND medication in combination with over-the-counter.

I particularly love Dr. Jen’s blog if you are considering supplements and medications or don’t even know where to start: Behavior Medication: First-Line Therapy Or Last Resort?

Feel free to reach out with questions, comments, or corrections. I acknowledge that my research is not exhaustive and there might be more out there that I haven’t found or understood!

References

Bartner LR; McGrath S; Rao S; Hyatt LK; Wittenburg LA. Pharmacokinetics of cannabidiol administered by 3 delivery methods at 2 different dosages to healthy dogs. Canadian Journal of Veterinary Reasearch. 2018, 82(3):178-183(6).

Bradley S; Young S; Bakke AM; Holcombe L; Waller D; Hunt A; Pinfold K; Watson P and Logan DW. Long-term daily feeding of cannabidiol is well-tolerated by healthy dogs. Front. Vet. Sci. 2022, 9:977457. doi: 10.3389/fvets.2022.977457

Brioschi FA; Di Cesare F; Gioeni D; Rabbogliatti V; Ferrari F; D’Urso ES; Amari M; Ravasio G. Oral Transmucosal Cannabidiol Oil Formulation as Part of a Multimodal Analgesic Regimen: Effects on Pain Relief and Quality of Life Improvement in Dogs Affected by Spontaneous Osteoarthritis. Animals 2020, 10:1505. https://doi.org/10.3390/ani10091505

Corsetti S; Borruso S; Malandrucco L. et al. Cannabis sativa L. may reduce aggressive behaviour towards humans in shelter dogs. Sci Rep 2021, 11:2773 https://doi.org/10.1038/s41598-021-82439-2

Deabold KA; Schwark WS; Wolf L; Wakshlag JJ. Single-Dose Pharmacokinetics and Preliminary Safety Assessment with Use of CBD-Rich Hemp Nutraceutical in Healthy Dogs and Cats. Animals 2019, 9:832. https://doi.org/10.3390/ani9100832

Gamble L-J; Boesch JM; Frye CW; Schwark WS; Mann S; Wolfe L; Brown H; Berthelsen ES and Wakshlag JJ. Pharmacokinetics, Safety, and Clinical Efficacy of Cannabidiol Treatment in Osteoarthritic Dogs. Front. Vet. Sci. 2018, 5:165. doi: 10.3389/fvets.2018.00165

Gugliandolo E; Licata P; Peritore AF; Siracusa R; D’Amico R; Cordaro M; Fusco R; Impellizzeri D; Di Paola R; Cuzzocrea S; Crupi R; Interlandi CD. Effect of Cannabidiol (CBD) on Canine Inflammatory Response: An Ex Vivo Study on LPS Stimulated Whole Blood. Vet. Sci. 2021, 8:185. https://doi.org/10.3390/vetsci8090185

Kulpa JE; Paulionis LJ; Eglit GM; Vaughn DM. Safety and tolerability of escalating cannabinoid doses in healthy cats. Journal of Feline Medicine and Surgery. 2021, 23(12):1162-1175. doi:10.1177/1098612X211004215

McGrath S; Bartner LR; Rao R; Kogan LR; Hellyer PW. A report of the adverse effects associated with the administration of cannabidiol in healthy dogs. Journal of the American Holistic Veterinary Medical Association. 2018, 52:34-38.

Morris EM; Kitts-Morgan SE; Spangler DM; McLeod KR; Costa JHC and Harmon DL The Impact of Feeding Cannabidiol (CBD) Containing Treats on Canine Response to a Noise-Induced Fear Response Test. Front. Vet. Sci. 2020, 7:569565. doi: 10.3389/fvets.2020.569565

Wang T; Zakharov A; Gomez B; Lyubimov A; Trottier NL; Schwark WS; Wakshlag JJ. Serum Cannabinoid 24 h and 1 Week Steady State Pharmacokinetic Assessment in Cats Using a CBD/CBDA Rich Hemp Paste. Front Vet Sci. 2022, Jul 22;9:895368. doi: 10.3389/fvets.2022.895368.

Yu CHJ and Rupasinghe HPV. Cannabidiol-based natural health products for companion animals: Recent advances in the management of anxiety, pain, and inflammation. Res. Vet. Sci. 2021, 140:38–46. https://doi.org/10.1016/j.rvsc.2021.08.001.