A growing number of pet owners are using cannabis-derived products with high doses of CBD (cannabidiol) and low or negligible doses of THC to alleviate pain, seizures, and other conditions. But what is known about the science of cannabinoid medicine and pets?

Unfortunately, not a lot. The question of using medical cannabis to improve the health of a dog or cat is a complicated one, and there isn’t a lot of solid, peer-reviewed research examining its safety or effectiveness. But that’s slowly changing.

In July 2018, the first clinical study examining the effects of hemp-based CBD on arthritic dogs was published in Frontiers in Veterinary Science, a leading international journal. The results were extremely encouraging.

In the study, Dr. Joseph Wakshlag of Cornell University and colleagues measured the effects of a particular hemp-based CBD product—ElleVet Sciences’ proprietary hemp oil blend—on pain and arthritis in a small sample of dogs.

The results were remarkable: More than 80% of dogs in the study saw a significant decrease in pain and improved mobility.

That’s only one study, though, and as promising as it is, nobody should rely on a single study to decide the right path for their dog or cat. It’s important to understand the political, ethical, and scientific implications of using medical cannabis in animals.

Most vets can’t touch CBD

You should know this up front: In many states, a veterinarian is not allowed to prescribe or recommend a cannabis product for your pet, regardless of the vet’s personal or professional opinion. Each state has its own veterinary board, and that board adheres to federal law concerning medical cannabis, so even if a state has legal recreational cannabis laws, your vet still may not be able to advise you.

“Vets have been restricted from getting involved,” said Dr. Gary Richter, a veterinarian based in Oakland, CA, who has advocated to allow the use of medical cannabis. “It was crazy that the 16-year-old kid at PetSmart could give you that advice, but I couldn’t.”

“Almost anything that cannabis would be used for in a human, from a medical standpoint, has the potential to be equally as valuable in dogs or cats,” said Richter. “Pain, inflammation, arthritis, gastro-intestinal related things, stress, anxiety, seizures, cancer, you name it. We’ve seen the benefits in all of these areas.”

Illegal states are tough

It’s even worse in states where cannabis is illegal for any purpose. For instance, contributing her own data to cannabis research has been almost impossible for Dr. Dawn Boothe, an internist and clinical pharmacologist at Auburn University in Alabama, according to an article published in VINNews, the website of the Veterinary Information Network.

“At Auburn University in Alabama, Boothe, the clinical pharmacologist, has had difficulty getting her clinical work off the ground, owing to the legal morass,” wrote reporter Edie Lau. “Alabama is one of 20 states where marijuana remains illegal for any purpose, although the state in 2016 created an industrial hemp research program overseen by its agriculture department.”

Only a handful of published studies on CBD and pets

As difficult as it is to research cannabis, a number of scientists have persevered and published solid peer-reviewed work. Their surprising results have piqued the interest of vets and pet owners alike.

In April 2017, American Veterinarian stated, “Concerning to many veterinarians is the lack of peer-reviewed clinical studies proving the efficacy of cannabis products for animals, yet another consequence of marijuana’s status as a controlled substance.”

The angle that has gotten the most vetting is that of marijuana’s toxicity to animals—in other words, dogs or cats accidentally eating their owner’s supply. Indeed, as far back as 2004, a study found that marijuana poisoning was possible in dogs, based on a milligram per kilogram, or weight proportionate, dosage.

That 2004 study found that “From January 1998 to January 2002, 213 incidences were recorded of dogs that developed clinical signs following oral exposure to marijuana, with 99% having neurologic signs, and 30% exhibiting gastrointestinal signs.”

The study in particular gauged what “poisoning” looked like in the animals. Researchers cited gastrointestinal signs as primarily vomiting, and neurological signs as depression, tremors, seizures, disorientation, hyperactivity, or stupor. Prior to that study, there were only a few surveys of cannabis-smoking teenagers who’d exposed their pets to secondhand THC.

Through the 2000s, there were only a few studies done on cannabis and dogs, all mostly corroborating the plant’s mild toxicity. The authors of a 2013 study conducted by a veterinary hospital in Denver observed that “Although the drug has a high margin of safety, deaths have been seen after ingestion of food products containing the more concentrated medical-grade THC butter.”

Dogs absorb CBD differently

The 2018 Cornell study on CBD and arthritis in dogs has given scientists an even deeper understanding of how cannabis works in the body of animals and by extension, humans, especially when it comes to absorption and dosage.

Previous to the Cornell study, cannabis pills were given to dogs on a fasted stomach in a 1988 study. It found that the form of CBD administered was poorly absorbed and did little to help the dog.

Study author Wakshlag said the oil base of the pill in their study accounted for the difference in results, whereas previous studies administered CBD intravenously or as a powder in a gelatin capsule.

What about CBD dosage in pets?

Another big challenge when it comes to cannabis and pets is finding the right dose for each animal. For CBD-only products, like the hemp oil from ElleVet Sciences, if they don’t offer a sufficient amount of CBD or if the CBD isn’t well-absorbed by the animal, you won’t see any change in the pet.

Thus, for Wakshlag, dosage was a prime concern, especially because there is little scientific evidence regarding how to safely and effectively dose a pet orally.

“The dosing [in our study] was basically modeled off of other doses that seem to have worked in a handful of studies in humans—somewhere between 1-5 mg per kg body weight,” said Wakshlag. “We chose 2[mg] because that would be a pharmacologically effective dose, and it wouldn’t be so expensive that it would preclude people from actually using it or buying it.”

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THC in pets is trickier

Wakshlag and his colleagues were able to find a good dose of a specific CBD-only product. The stakes change, though, when you add THC into the mix. In fact, many vets and researchers suggest people refrain from giving pets any amount of THC at all.

“THC is actually toxic for dogs. So, of course we wouldn’t want to give dogs THC at all,” said ElleVet’s founder Amanda Howland. For that reason, ElleVet’s products, including the oil used in the Cornell study, are all hemp-based—hemp is defined as cannabis containing less than 0.3% THC content.

The THC issue isn’t a settled question, though. Oakland veterinarian Gary Richter believes in the efficacy of THC as medicine for animals. He’s seen its benefits in his own dog, Leo. Richter also works to educate vets and pet owners about cannabinoid medicine through webinars, lectures, and online continuing education courses.

“The research is very, very clear from the human literature standpoint that there’s medical benefits to THC,” Richter told Leafly during a phone interview. “And while certainly the relative sensitivities are different for people versus animals, we all have a very similar endocannabinoid system. There is no reason to think that THC is beneficial in people when it’s somehow poison to dogs and cats.”

“The thing that troubles me is that you’ve got animals out there that could be benefiting from products with THC in them, and not only are pet owners shying away because of this information but you’ve got veterinarians that are believing this and saying that you should never give an animal something with THC in it,” said Richter.

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The right cannabinoid combo

Instead of abstaining from THC altogether, Dr. Richter advises doing research into whether THC might help your pet’s particular ailment—and if so, start with a very small dose.

“The two big players are THC and CBD, but there are so many other compounds within cannabis,” said Richter. “There are other cannabinoids and terpenes and there are things in the product that are going to vastly change its behavior as a medicine. Depending on what’s being treated, the first question is: ‘What is the most ideal combination of these various compounds that will benefit an animal?’”

Overall, Richter says the best way to keep your pet from getting sick from cannabis is to consult with a veterinarian as you dose.

Amazing pet turnarounds with CBD

The results of medical cannabis in dogs and cats with a variety of ailments has been very promising.

The Cornell study showed that once the right dosage is determined for your pet, CBD can improve arthritis pain. The study involved a small sample size, only 16 dogs, all with a lot of pain from chronic arthritis, and each dog saw significant improvement.

“We had one that the owner was really ready to euthanize the dog and this trial was a last-ditch effort,” said ElleVet founder Howland. “Once she was in the test group, the dog did so well and completely turned around. It’s almost two years later and she’s still alive and doing well.”

“I believe we really scratched the surface in regard to how this could be used from an overall pain perspective,” said Joseph Wakshlag, leader of the Cornell study. “If my dog ever has chronic arthritis, this would be one of the things I’d definitely use.”

Gary Richter’s own dog, Leo, suffers from seizures that are the result of brain damage that occurred during a dog attack. After trying multiple pharmaceutical medications, the Oakland veterinarian put Leo on a cannabis preparation. Richter observed a marked change: “He went from having multiple seizures per week to having one or two per month.”

In addition to the research at CSU and other institutions, there are more and more anecdotal accounts of cannabis-based medicine helping dogs with behavioral and gastrointestinal issues as well.

“It really does have a great anti-anxiety affect,” said ElleVet company founder Howland. “We’ve had a number of vets in Florida try it with some of their patients who really freak out during thunderstorms. We had amazing reports about dogs who’d [previously] hurt themselves or throw themselves through windows during thunderstorms; it’s really calmed them.”

The company has also seen results with irritable bowel syndrome and autoimmune disorders like Crohn’s disease.

What about cats and CBD?

Unfortunately, there isn’t much data when it comes to cannabinoids and cats. ElleVet did find their propriety hemp blend to be helpful to cats, but Howland stressed that cats respond much differently to cannabis than dogs.

“Cats are absolutely not small dogs and they metabolize things very differently,” said Howland. “Cats can’t take any of the drugs that dogs take for pain. Their livers just don’t tolerate it.”

If a human tries to help an ailing cat by giving it a canine pain reliever, “They can get very sick. There are very few pain options for cats that are safe.”

ElleVet did a long-term safety study to determine if their products are safe for cats and found that for the treatment of anxiety, cats responded better to cannabinoid medicine than dogs. Cats also saw decreases in pain from arthritis and other problems, like dogs. But their hemp oil left a cat’s body after only two hours in cats, meaning they need a much higher dose more frequently than a dog of the same size.

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Curious about CBD for your pet? Do your research

Many pet owners are curious about cannabis-based treatments for their ailing companions. The market for CBD products for dogs and cats is booming. But Richter acknowledges that changing the attitude of medical professionals toward the use of medical cannabis with pets is slow, hard work, and will continue to be for the foreseeable future.

“We’ve seen the benefits in all of these products,” said Richter. “The science is here, but as is typical with the medical community, you’re going to have a pretty sizeable group in the medical community that will refuse to accept any of it until it’s documented in research.”

Still, he trusts that the research will continue to show cannabis as a positive medical option for the treatment of dogs and cats. Because of that, Richter and many others who’ve seen the firsthand effects of cannabis medicine in animals, don’t see a point in waiting to start helping pets.

“While I am certainly a person who’s a proponent of the research,” he said, “Just because the research isn’t there doesn’t mean you can or should ignore something that’s completely obvious and right in front of your face.”