Cannabidiol (CBD) for Dogs - The Basics

What is CBD? 

There’s a lot of buzz about CBD these days. Anecdotal evidence on the therapeutic benefits of CBD for dogs is booming,^1,2 making it a hot research topic in current clinical trials. 

But what is it, exactly? And how can it benefit your dog?

Cannabidiol (aka CBD) is one of the many naturally occurring chemical compounds (aka cannabinoids) found in cannabis plants like hemp and marijuana.³ CBD is not the same as Tetrahydrocannabinol (aka THC), another cannabinoid. THC is widely known for its psychoactive properties — and while it’s used by humans for both recreational and medical reasons, it has been found to be toxic to dogs at high doses.^1,4 While CBD does impact the nervous system,^5,6 it does not produce the “high” associated with THC.

 

Where does CBD come from?

CBD can be extracted from both hemp and marijuana sources, but only hemp-derived CBD is federally legal... sort of. We’ll talk more about legality in another post.⁷ 

Speaking of hemp and marijuana, what’s the difference? While they both can be varieties of the plant Cannabis sativa, their chemical compositions are quite different, and growing practices have led to differences in appearance and cultivation of the crops.⁸ The difference in chemical composition is what separates them legally. Hemp contains low levels of THC and higher levels of CBD⁸ and is legally defined as a cannabis plant containing no more than 0.3% THC on a dry weight basis.^4,9 Marijuana, as you might expect, has higher levels of THC, and varying levels of CBD.⁷ Unlike hemp, marijuana is currently federally illegal and considered a Schedule 1 drug.¹ Here’s a chart further explaining the plants’ differences. 

Comparison of Hemp vs. Marijuana

Hemp	Marijuana
A cannabis plant containing < 0.3% THC, with varying levels of CBD and other cannabinoids	Cannabis plant containing varying levels of THC, CBD, and other cannabinoids
When grown for fiber, plants are tall and densely planted, with few branches and leaves. When grown for cannabinoid content, high-CBD, low-THC seeds are grown to be bushy and encourage flowering.10	Mainly grown for medicinal purposes, to maximize THC content. Plants are grown to be bushy and short, with many flowers, and are well-spaced.10
Analysis of hemp plants found CBD to be the most prevalent cannabinoid.11	Study of marijuana samples in Northern Thailand revealed THC levels ranging from 0.41 - 3.05% by dry weight, and CBD levels ranging from 0.015 - 0.24% by dry weight in fresh marijuana plants.12
Analysis of modern hemp varieties revealed most plants to be in line with a non-drug type THC/CBD ratio of 1/20, and most had THC contents < 0.3%.13	Seized marijuana in California revealed an increase in THC levels from 4.56% (1996) to 11.75% (2008), and a decrease in CBD 0.24% (1996) to 0.08% (2008) levels.14

How does CBD work?

Like humans and other mammals, dogs have what’s called an endocannabinoid system (ECS).^1,4 This system contains activators and receptors that are thought to impact a variety of physiological processes, including immunity, pain, sleep, memory, and more.^4,15 

The ECS communicates with the body’s cannabinoid receptors, which are located throughout the body. CB1 receptor are located in the central nervous system (including the brain and the spinal cord) and CB2 receptors are located in the peripheral nervous system.^1,16 Exogenous cannabinoids such as CBD can interact with these receptors, and in the case of CBD appear to benefit the body’s homeostasis of the nervous system such as better sleep and less anxiety.¹⁷

At this point in time, researchers don’t know exactly how CBD works in the canine body. However, there are some theories. Unlike most pharmaceuticals, it is thought that CBD may have a dual property to either increase or decrease neural signaling in order to meet the body’s needs.¹⁷ CBD may also act on the immune system through the ECS. This is because cannabinoid receptors are also present on immune cells, and CBD has the ability to induce immune cell death.^18,19

CBD appears to take effect in just 30-60 minutes, before being eliminated by the liver via a metabolic process.^20,21 There is some variation in the time it takes CBD to leave the body, averaging around 4 hours. This suggests that multiple doses are required daily for prolonged effects.^22-24

The use of CBD in dogs is proving to be very promising in veterinary medicine, and, as a result, there has been a rapid increase in the availability of CBD pet products on the market.

How can CBD benefit my dog? 

While evidence surrounding the benefits of CBD oil for dogs is mainly anecdotal, clinical trials are underway and results are encouraging. And emerging results from research studies are beginning to legitimize the reported benefits. 

This anecdotal evidence suggests that CBD can help with a long list of health problems in dogs, including seizures and epilepsy, a variety of cancers, digestive disorders, skin issues, cardiac conditions, anxiety and depression, and issues related to inflammation and pain, notably arthritis.^3,25,26

Studies have also been done confirming the connection between the endocannabinoid system and canine idiopathic epilepsy,²⁷ as well as osteoarthritis.²⁸ This supports the idea that CBD can influence and help with these conditions. It’s important to note, however, that some products labeled “CBD oil” are actually full-spectrum hemp oils and rich in other non-THC cannabinoids and terpenes. As a result, a product used in one study may not be the same as one used in another.

For more on the current anecdotal and clinical evidence for the use of CBD to help common health problems in dogs, see the table below.

 

Evidence supporting CBD use in dogs

Health Problem	Anecdotal Evidence	Scientific Evidence
Epilepsy	Strong evidence in humans to help control seizures, FDA approved drug EPIDIOLEX®.29 CBD has anticonvulsant properties. Dog owners report CBD as lessening the intensity, occurence rate, and duration of seizures in dogs.3 Epilepsy interferes with endocannabinoids and bodies homeostasis, and providing CBD is believed to help restore this balance.30 A survey on consumer’s perceptions of hemp products for animals found ~30% of respondents saw a moderate - great decrease in seizures/convulsions in dogs, the majority of respondents said NA or “don’t know”, and only ~2% said it helped very little or not at all.6	Yes:31 McGrath et al. (2019) Type: Randomized blinded controlled study. Treatment: Dogs with idiopathic epilepsy currently on anticonvulsant therapy additionally receive 2.5mg/kg CBD or placebo, 2x daily for 12 weeks. Results: 89% of dogs on CBD had significant reduction in seizure frequency.32 No adverse behavioral effects, but increased ALP levels (a liver enzyme measured on bloodwork) and 2 cases of ataxia (poor neurologic control of the limbs) seen while giving the supplement. ----------------------------------------------------------- Upcoming: AKC Canine Health Foundation is funding larger randomized, double-blind, placebo-controlled, crossover clinical trial under their Epilepsy Research Initiative looking at the effects of CBD on seizures in dogs at Colorado State University.5,33
Osteoarthritis (Joint Pain & Inflammation)	CBD interacts with the cannabinoid receptors in the dog, and can help reduce inflammation and associated pain.  A survey on consumer’s perceptions of hemp products for animals found ~65% and ~42% of respondents saw a moderate - great improvement in pain relief and reduced inflammation, respectively in dogs.6 An additional report found that 60.2% and 48.7% of dog owners using hemp/marijuana products were using them to treat pain and inflammation, respectively. Further, approximately 75% and 73% found them as effective or more effective than conventional treatment meds, for treating pain and inflammation, respectively.34	Yes:23 Gamble et al. (2018) Type:  Randomized placebo controlled, blinded crossover study. Treatment: Dogs with osteoarthritis (OA) provided 2mg/kg CBD oil or placebo, every 12hr for 4 weeks. Results: With CBD treatment, decreased pain and increased activity reported. No reported side effects, except increased ALP levels. ----------------------------------------------------------- Yes:35 Mejia et al. (2019) Type: Prospective, double-blind, crossover, placebo-controlled. Treatment: Dogs with OA on conventional treatment medication were given 5mg/kg CBD or placebo for 6-weeks. Results: Significant differences in some outcome measures suggest the efficacy of CBD for relieving pain in dogs with OA. However, some inconsistent results and an increase in liver enzymes seen in dogs taking CBD.
Cancer	Positive impacts seen with CBD treatment on dogs with cancer include increased immune strength, decreased dependance and side effects of medication, cancer cell death, reductions in tumor size, and overall improvements to quality of life.4,25 CBD is thought to help with pain associated with cancer in dogs by interacting with cannabinoid receptors.26 A survey on consumer’s perceptions of hemp products for animals found ~10% of respondents saw a moderate to great decrease in tumors/cancer cells in dogs, but the majority of respondents (87%) replied “not applicable” or “don’t know”, and only ~3% said it helped a little or not at all.6	None ----------------------------------------------------------- Upcoming: The University of Florida College of Veterinary Medicine is preparing a pilot study looking at the use of CBD oil on dogs with lymphoma undergoing chemotherapy.36 Inclusion: Any dog (>15 kg) that has a lymphoma diagnosis and is currently being treated with conventional chemotherapy methods. Treatment:  Dogs will be randomized to receive CBD oil (dose based on size) or placebo every 12hrs, starting at week 4 or 5 of chemotherapy treatment and continuing for 5 weeks. ----------------------------------------------------------- Upcoming:37 Colorado State University is studying the effects of CBD oil on canine gliomas, a cancerous brain tumor. CBD therapy alone and in conjunction with chemotherapy is being assessed.  ----------------------------------------------------------- Expert Opinion: Stephanie McGrath, MS, DVM, DACVIM (Neurology) of Colorado State University has made statements of interest in studying the effects of CBD on various cancers in dogs.4
Anxiety	CBD is believed to help produce a more relaxing state, through its interaction with cannabinoid receptors.3,26 Further serves to release serotonin and dopamine, which can boost mood and sleep quality.3,4 A survey on consumer’s perceptions of hemp products for animals found that dog owners listed anxiety as one of the main reasons for using cannabis products. Further, dog owners noted cannabis products as benefiting noise phobia, produced during occasions like thunderstorms.6 Owners have also noted CBD as benefiting separation anxiety.6,25 Further, 47.1% and 17.8% of dog owners reported using cannabis products for relief from anxiety and thunderstorm phobia, respectively. And ~70% found it more effective or as effective as traditional medications.34	None ----------------------------------------------------------- Expert Opinion: Stephanie McGrath, MS, DVM, DACVIM (Neurology) of Colorado State University has made statements of interest in studying the effects of CBD on anxiety in dogs.4 ----------------------------------------------------------- In Humans:38 Crippa et al. (2011) Type: Double-blind placebo controlled study Treatment: Subjects with social anxiety disorder (SAD) were enrolled and provided 400mg CBD or placebo. Results: Subjects receiving CBD showed significantly reduced anxiety. ----------------------------------------------------------- Review of Animal Models:39 de Mello Scier et al. (2014) Results: A review of 15 studies, mainly in rat and mouse models, for the use of CBD on depression or anxiety confirmed the anti-anxiety effects of CBD in animal models.
Irritable Bowel Disease & Digestive Disorders	CBD is believed to help reduce the inflammation present in the intestine and well as modulate immune system.3,25 A survey of consumer’s perceptions towards canine hemp products reported that ~17% of respondents saw a moderate to great impact on digestive problems, the majority of respondents said “not applicable” or “don’t know”, and ~7% said it helped very little or not at all.6	None ----------------------------------------------------------- Emerging studies in humans and animal models are demonstrating the potential therapeutic benefits of CBD on the digestive tract. Human studies are displaying its benefit on inflammation and “leaky-gut”.40 Additionally, CBD in conjunction with other cannabinoids was demonstrated to protect against intestinal damage from colitis in mice.41 There are a number of other animal and human studies emerging demonstrating similar effects. However, studies in dogs currently do not exist.
Skin and Coat Conditions - including allergies	Anecdotal evidence supports the use of CBD oil to improve canine skin and coat conditions but the effect could be from the oil alone.25  A survey on consumer’s perceptions of hemp products for dogs reported that ~13% of respondents saw a moderate - great impact on skin problems, the majority of respondents said “not applicable” or “don’t know”, and ~8% said it helped very little or not at all.6 Another report indicated that allergies was one of the most common “other” responses listed, when dog owners were asked which conditions they were using cannabis products to treat.34	None ----------------------------------------------------------- Cannabinoids and Skin:42 Campora et al. (2012) Implications: While this study did not look at CBD on skin disorders in dogs. It did however display that cannabinoid receptors, CB1 and CB2 were immunoreactivity was found to be higher in the skin of dogs with atopic dermatitis (allergic inflammatory skin condition) than healthy controls, indicating the potential of CBD and a therapy for allergic skin diseases in dogs.

 

What have other dog owners experienced?

Two surveys reported in the Journal of the American Holistic Veterinary Medical Association looked at dog owners’ perceptions and use of hemp and cannabis products.^6,34 The 2016 survey found that 58.8% of respondents were currently using a hemp product for their dog, and of those that had discontinued use, only 4.6% cited negative side effects as the reason.⁶ The most common conditions survey respondents listed as their reason for trying canine hemp products: seizures, cancer, anxiety, and arthritis, as diagnosed by a veterinarian.⁶ Additionally, dog owners reported moderate to great improvements in issues related to pain, sleep, and anxiety, and the most noted side effects were sedation and increased appetite.⁶

The 2018 study reported that dog owners used canine cannabis products most commonly to treat pain, inflammation, and anxiety-related conditions, as well as cancer, arthritis, and seizures. Dog owners found the cannabis products to be more than or just as effective as traditional treatment methods, for all conditions, with minimal side effects.³⁴ 

These studies demonstrate that, despite the limited clinical evidence supporting the therapeutic use of CBD, dog owners value anecdotal evidence and testimonials in support of these products, and are further perceiving and experiencing cannabis products as safe and superior to conventional treatments. The vast number of positive testimonials from pet owners is powerful and and helps encourage continued scientific experiments and studies.⁴

 

What do vets think? 

While many dog owners support the use of canine cannabis products, legal complications unfortunately often hamper veterinarians’ ability to freely discuss the use of CBD with pet owners.⁴ This leaves pet owners on their own to seek information, which can be dangerous. It was reported that despite dog owners indicating that they felt comfortable discussing cannabis with their vet, they still relied mainly on CBD product websites for information, as current laws limit vets’ ability to openly share their perspectives on canine CBD products.³⁴ 

A 2018 survey looking at veterinarians’ knowledge, experience, and perception of canine CBD products found that only 45.5% of vets felt comfortable discussing CBD use with pet owners. 85% said they never or rarely initiated the conversation, and this often depended on the legalization status of cannabis in the state.⁴³ The majority (91%) reported that they rarely or never prescribe CBD products, and 83% and 73%, respectively, stated that they rarely or never recommend or advise CBD use. Reasons cited included lack of research, lack of knowledge, and legality concerns.⁴³ 

Still, there are many vets that advocate for CBD’s efficacy. The 2018 survey on veterinarian views towards cannabis and CBD products found that vets with clinical experience using CBD products in dogs found CBD to be very helpful for ailments associated with pain, anxiety, seizures, fear, and vomiting. CBD use was not perceived as harmful by the majority of vets, who also reported no effect for conditions such as diarrhea, diabetes, and bacterial infections.⁴³ As with pet owners, sedation and increased appetite were some of the primary side effects vets noted.⁴³

 

What’s the bottom line?

Despite the ever-changing legal status of CBD products for dogs, many pet owners and veterinarians see the therapeutic potential they have to offer.

And even with limited clinical studies, sales of cannabis pet products are skyrocketing. One report indicated a 1000% increase in sales between September 2016 and 2017.³⁴

The need for more clinical studies is apparent, but current legality concerns can pose an issue for researchers. While side effects of CBD can be a concern for pet owners and veterinarians, the reports of positive effects are encouraging. Additionally, the significant negative impacts of conventional medications (such as nonsteroidal anti-inflammatory drugs’ (NSAIDs) impact on the kidneys and liver) are pushing pet owners to seek more natural therapies like CBD.^3,23

The bottom line is that CBD products are generally perceived as safe and effective.⁶ Dog owners are starting to give CBD products to their healthy dogs, due to the anecdotal evidence supporting its impact on quality of life and overall wellbeing.²⁵ This not only further drives the need for more clinical studies, but also requires information on product quality standards to be reliable and accessible to pet owners, so consumers can purchase products that are safe for their dogs.

Please don't forget to check out our articles on important things to consider before giving CBD to your dogs, as well as the legality of CBD use in the US.

References:

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