As people continue to live longer and lead increasingly stressful lives, the number of people suffering from painful, chronic conditions increases. One of the most common chronic conditions is arthritis, affecting more than 50 million adults in the United States – that is 1 in 4 individuals over the age of 18. (5)
In recent times, the popularity of natural remedies and plant-based treatments for a wide variety of conditions has been increasing, as have studies to delve into the effectiveness of such remedies.
Cannabidiol, or CBD, is one such supplement that many arthritis patients claim helps them with their pain. The question that many of our readers ask is whether or not there is solid science out there to support these claims?
Does hemp oil help with arthritis pain? If so, how does cannabidiol work to reduce pain, and what side effects are associated with CBD?
In this article we will delve into what scientists have found thus far in their quest to understand how CBD products work and who may benefit from their use.
As the number one cause of disability in America, arthritis likely reaches you or someone close to you. The pain and stiffness caused by arthritis can have a dramatic impact on one’s mobility, limiting their ability to work, play, walk, or even sleep soundly.
There are numerous forms of arthritis, with over 100 types of arthritis and similar conditions. (5) With all of these conditions, joints and connective tissues are damaged, leading to chronic pain.
The two most common forms of arthritis are rheumatoid arthritis (RA) and osteoarthritis (OA), hence most of the studies on how CBD and other cannabinoids impacts arthritis symptoms has been focused on those suffering from these conditions.
In RA, a person’s body attacks their joints, which leads to inflammation and damage. Most commonly, RA leads to painful, stiff, and swollen joints in the hands and feet.
OA is a degenerative disease which affects cartilage, joint, and bones. Hip, knee, and thumb pain and stiffness are common symptoms of OA.
The pain in these diseases is largely thanks to the manifestation of inflammation, thus medications and supplements that are able to fight inflammation or reduce feelings of pain (anti-nociceptive abilities) are of crucial importance for those suffering from arthritis.
The Endocannabinoid System and Arthritis
The endocannabinoid system (ECS) is made up of three fundamental components: the endocannabinoid signaling molecules, cannabinoid receptors (CB1 and CB2 receptors), and the enzymes involved in ligand inactivation and biosynthesis. (4)
Mapping of these parts of the ECS has led to the discovery that they exist throughout peripheral nerve terminals and up to supraspinal centers – this is the pain pathway.
Studies have found that the endocannabinoids produced by our bodies are capable of attenuating and suppressing our perception of pain.
Arthritic pain results from both the irritation of sensory nociceptors (nociceptive pain) as well as the malfunctioning of the somatosensory nervous system (neuropathic pain). (4) Inflammation is largely responsible for the nociceptive pain.
CB1 receptors, CB2 receptors, and FAAH (fatty acid amide hydrolase, an enzyme involved in the ECS) have been found to be expressed in the synovial membrane in OA and RA patients. Evidence supports the hypothesis of these components of the ECS being involved in the pathophysiology of joint pain. (4)
With the ECS being intricately involved in the pain pathway, the possibility of targeting this natural system to reduce pain is of particular interest to many researchers.
What Exactly is CBD?
One possible way of targeting the ECS to reduce pain is through the use of phytocannabinoids, cannabinoids that occur in plants and are capable of acting on the ECS in a wide variety of ways.
CBD (cannabidiol) and THC (tetrahydrocannabinol) are two of the most well-researched and understood phytocannabinoids when it comes to therapeutic potential. They both come from the Cannabis sativa plant, which encompasses both hemp and marijuana plants, in which there exist 80 or more naturally occurring cannabinoids.
THC traditionally comes from marijuana plants, which have been bred to increase the percentage of THC, while CBD traditionally comes from hemp plants, some of which are currently being bred to increase the percentage of CBD.
THC and CBD appear to exert their effects on the body through their interaction with the ECS.
While the most widely known component of the cannabis plant is THC, which is known for its psychoactive properties, CBD is capable of interacting with our ECS without causing any mental alterations.
The effects of THC can range from very mild in some to severe in others, which leads some to desire cannabinoid products that do not contain any THC. THC is also illegal in many states, making THC-free products easier to acquire.
The lack of psychoactive effect is one of the biggest reasons that CBD only products are of such high interest to researchers and to individuals who suffer from a variety of ailments and are looking for help from nature.
Cannabidiol and Arthritis
Animal studies have supported the idea that the immunosuppressive and anti-inflammatory role of CBD may be useful in treating rheumatoid arthritis and the pain that comes with it. (6)
Oral and Injectable CBD in Mice with Collagen-Induced Arthritis, a Model of RA
In a 2000 study published in the Proceedings of the National Academy of Sciences of the U.S.A., the effect of oral and injectable cannabidiol in mice with collagen-induced arthritis (CIA) was examined. (3)
CIA was elicited in mice as a model of rheumatoid arthritis in two different ways, one leading to classical acute CIA and the other chronic relapsing CIA.
Both sets of mice were split into groups for CBD treatment that included: injections of CBD ranging from 2.5 mg/kg to 20 mg/kg, control group receiving injections without CBD, oral CBD dissolved in olive oil ranging from 10 mg/kg to 50 mg/kg, or oral olive oil without CBD.
Based on a large number of measurements intended to measure protection against severe joint damage, the researchers concluded that CBD was effective at blocking the progression of arthritis, both orally and through injection. The dose dependency showed a bell-shaped curve, meaning that doses below and above the optimal dose were less effective.
For mice with CIA, the optimal dose for injection was found to be 5 mg/kg per day and the optimal dose for oral CBD was 25 mg/kg per day.
The researchers further concluded that this data suggests that this anti-arthritic effect of CBD against CIA in mice was due to its anti-inflammatory and immunosuppressive actions.
CBD Prevents Pain and Nerve Damage in Rats with Osteoarthritis
In a December 2017 study published in Pain, researchers evaluated the impact of cannabidiol on pain and nerve damage caused by the inflammation due to osteoarthritis in rats. (2)
This study looked at both CBD given early in the progression of OA in the hopes of preventing future arthritis symptoms as well as local CBD treatment once joint inflammation from OA was already underway.
The researchers concluded that local administration of CBD blocked osteoarthritis pain, and that prophylactic treatment with CBD prevented the development of nerve damage and nerve pain in the joints. Their finding suggest that CBD may be a safe and effective treatment for the pain and damage caused to joints by OA in rats.
Topical Cannabidiol Reduces Pain-Related Behaviors and Inflammation in Arthritic Rats
CBD can be taken in many forms, with one application strategy being topical administration applied directly to the skin where individuals are suffering from pain or stiffness. (9)
With topical CBD, the hope is that serum CBD levels may raise more than if consumed orally due to avoidance of digestion, where first pass metabolism removes much of the CBD from the body.
In a 2016 study published in the European Journal of Pain, the effectiveness of transdermal CBD in the reduction of inflammation and pain-related behaviors in rats with arthritis was evaluated.
Topical CBD gels of 0.6, 3.1, 6.2 or 62.3 mg/day were applied for 4 days following the introduction of arthritis in rats.
Levels of inflammation for each group were evaluated using immune cell invasion and joint circumference measures. Exploratory behavior was used to determine activity level, and paw withdrawal latency in response to heat was used to determine nociceptive sensitization. Additional measures were also taken to measure pro-inflammatory biomarkers.
It was found that absorption increased linearly with the 0.6 mg/day to the 6.2 mg/day. Only the 6.2 and 62.3 mg/day were found to be effective doses for reducing joint swelling, pain ratings, and pro-inflammatory biomarkers. No side effects were found.
This study demonstrates that topical application of CBD has the potential to reduce pain and inflammation associated with arthritis in rats without evident side effects.
The human studies thus far have concentrated on the impact of a combination of CBD and THC on pain relief, so further human studies on the impact of CBD without THC are needed.
CBD+THC and Arthritis
A 2005 study published in Rheumatology investigated the effectiveness of an Sativex, an oromucosal spray with a THC:CBD ratio of roughly 1:1, on reducing pain in rheumatoid arthritis patients. (7,8)
58 patients were selected for a 5 week parallel group, randomized, double-blind study where they either used Sativex spray or a placebo spray daily. The researchers concluded that Sativex, in comparison to placebo, resulted in significant improvements in pain during rest and movement, pain at present, and quality of sleep. Between the placebo group and the Sativex group there was no significant difference in morning stiffness.
Even though this product contains THC, the psychoactive component of cannabis, the side effects ranged from mild to moderate, and no serious adverse effects or withdrawal symptoms were found.
CBD Oil for Arthritis Summary
Studies examining the effectiveness of pure CBD oil against arthritis pain are almost all animal studies, with more research needed before it is possible to have a definitive answer as to how CBD products impact arthritis pain in humans.
These studies that have been conducted show positive results when CBD is administered to rats and mice in the pain and progression of a variety of forms of arthritis.
As human studies on arthritis pain relief have been for a combination of THC and CBD, we do not have studies to help inform us on specific efficacy and dosage for humans. That said, this does not mean that CBD would not be effective on its own, however further studies need to be conducted to determine its effectiveness and ideal dosage.
Are CBD Products Safe?
With the addition of any new supplement it is recommended to speak with your physician. One of the more common side effects of CBD is the possible interaction with other drugs.
Studies examining the side effects of CBD tend to come up with no noticeable side effects up to mild side effects, such as mental sedation. (10)
It appears that doses of CBD up to 1,500 mg/day and chronic use of cannabidiol is well tolerated, however there are limited studies and further research is needed to fully understand the side effects of CBD. (11)