advocates tout a for humans -- but can it help our four-legged friends too? The answer is complicated.
When Colorado legalized recreational marijuana in 2012, it wasn't something veterinarian Stephanie McGrath thought much about day to day. But then the phone calls started coming. Pet owners and family veterinarians wanted to know what she thought about medical marijuana in relation to animals, and whether she was researching it.
This story discusses substances that are legal in some places but not in others and is for informational purposes only and not for the purpose of providing legal advice. You shouldn't do things that are illegal -- this story does not endorse or encourage illegal drug use.
At the time, McGrath had no interest in cannabis and didn't even know whatwas, so she mostly ignored the topic. But the combination of receiving phone calls and seeing CBD products already lining pet store shelves made her realize she needed to get up to speed.
"Around 2013 or 2014, I started looking into what research was already out there and I realized that there was essentially no real, good scientific literature in the human world, let alone the veterinary research world," says McGrath, assistant professor of neurology at Colorado State University College of Veterinary Medicine and Biomedical Sciences. "And so I started investigating whether it would even be plausible for me to conduct any research."
McGrath went on to become one of the pioneering researchers in the field of veterinary cannabis but even with her early efforts, research (and regulation) has struggled to keep pace with demand, as people increasingly turn to CBD products to treat their pet's pain, anxiety and seizure disorders.
Thanks in large part to the 2018 Farm Bill, which legalized hemp-derived CBD, analysts now predict the CBD pet care market will reach $125 million by 2022, making it one of the fastest-growing segments of the CBD market.
For such a rapidly growing industry, there are still a lot of unknowns. Below, what you need to know if you're considering CBD for your furry friend.
What is CBD?
Cannabidiol is part of the cannabinoid family, a class of chemical compounds naturally found in the cannabis plant. Cannabinoids interact with the human body's endocannabinoid system, which helps the body maintain homeostasis.
Unlike its cousin delta-9-tetrahydrocannabinol, or THC, CBD doesn't produce a "high," but it is psychoactive. In 2018, the US Food and Drug Administration approved Epidiolex, an oral CBD solution, to treat Lennox-Gastaut syndrome and Dravet syndrome, two rare and severe pediatric seizure disorders. CBD is also being investigated as a possible treatment for anxiety and schizophrenia symptoms in humans.,
How is CBD administered to animals?
CBD pet care products come in many of the same forms you're probably used to seeing for humans, including edibles (think: chewable treats and capsules), oils that can be added to food or placed under the tongue and topical creams or balms that are rubbed directly on the skin.
Like the CBD products meant for humans, each of these CBD pet care product types appears to have a different effect on the body -- in dogs, anyway.
When McGrath started studying CBD in 2016, one of her first studies analyzed how three different delivery methods -- a capsule, an oil and a cream -- affected the way CBD moved through the bodies of healthy dogs.
"We measured the pharmacokinetics, which basically means you give the dogs a single dose of all three delivery methods and then you measure a bunch of different blood levels over a 12-hour period," says McGrath. "So how quickly is the CBD absorbed, how high the blood concentration gets at that single dose, and then how fast the CBD is eliminated."
McGrath found that, out of the three specific formulations they tested, the oil had the best pharmacokinetic profile, meaning it reached the highest concentration in the blood, stayed in the bloodstream the longest, and performed the most consistently across different types of dogs. The capsule also performed well but the cream less so. It performed too inconsistently for McGrath and her team to draw any conclusions.
These results line up with what we know so far about CBD absorption in humans, but the research is too preliminary to be used to make any medical decisions.
How does CBD work in animals?
It's unclear -- and a puzzle researchers are still trying to solve in humans as well. For instance, dogs have an endocannabinoid system but whether CBD interacts with it in the same way experts think it does in humans remains to be seen. For now, all McGrath knows is that in dogs, like in humans, CBD appears to be metabolized by the liver.
Are there any health benefits to giving your pet CBD?
Research is promising, but it's still early. A randomized, double-blind, placebo-controlled study published in the journal Pain in 2020 found that "Cannabidiol possesses potent anti-inflammatory properties and significantly improved the mobility of large domestic canines afflicted with osteoarthritis."
This research follows a 2018 study found that CBD can help increase comfort and activity in dogs with osteoarthritis.
In 2019, McGrath published a study showing CBD may help reduce the number of seizures experienced by epileptic dogs. But although these studies were well-designed and peer-reviewed, they're still small and very preliminary.
"All we've basically done is give this drug to these dogs and said, OK, this is what we're seeing," says McGrath. "But whether or not the blood levels achieved are adequate enough to treat certain diseases, we don't yet know."
Still, McGrath is optimistic. Veterinarians don't have a wide variety of drugs available to treat these conditions and some of the ones that do exist often come with debilitating side effects, such as weight gain and lethargy. "If CBD works, then I think it would hit the mark of being both effective and not carrying a lot of side effects," says McGrath. "So that's kind of what we're hoping for."
McGrath and other researchers nationwide are currently conducting larger studies on CBD's effectiveness in treating osteoarthritis in dogs and cats, epilepsy in dogs and post-operative pain, but it will be a while before the results are published.
Until more is known, it's best to talk to your veterinarian before giving your animal CBD.
Is CBD safe for animals?
CBD, in its pure state, appears to be safe and well-tolerated by animals, according to a 2017 World Health Organization report. However, both subsequent 2018 canine studies mentioned above noted an increase in the liver enzyme alkaline phosphatase (ALP) during CBD treatment.
As part of her study, McGrath ran a simultaneous liver function test to make sure the dogs' livers weren't failing and everything came back normal, so it's unclear whether the elevated ALP levels were caused by something completely benign or could develop into a more serious problem long term.
"I would definitely be a little concerned about giving CBD to a dog that has known liver issues," says McGrath. Similarly, because CBD appears to be metabolized by the liver, McGrath says she'd also be wary about giving CBD to a dog who already takes a medication that's metabolized by the liver. "We don't really know how these things interact right now," she says.
The other big thing pet owners need to be aware of is quality control. Because the CBD market isn't well regulated yet, CBD products can contain ingredients that aren't listed on their labels -- including THC, which is known to be toxic to cats and dogs.
One way to avoid potentially harmful ingredients is to only use products that come with a certificate of analysis, or COA (the batch number on the COA should match the number on the product's label or packaging). A COA is issued when an independent lab tests the product to confirm its ingredients and potency, among other things.
Legally, CBD products must contain no more than 0.3% THC, which should be safe for animals. But there's no reason to take chances. Whenever possible, stick to CBD pet care products that contain 0.0% THC and be on the lookout for symptoms of THC poisoning such as vomiting, diarrhea, lethargy, restlessness and trouble standing.
Bottom line: "We haven't found anything that's super alarming about CBD," says McGrath. "But on the flip side, we still know very little about it, and it's really important for owners to know that and use it with caution until we have more information."
The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.