Since the Canadian legalization of medical cannabis in 2001, cannabis-based products designed for treating osteoarthritis (OA) have been on the rise.
OA is the most common form of arthritis and occurs when the protective cartilage that caps the ends of your bones begins to wear down over time. As the cartilage disappears, the bones at the joints eventually begin rubbing together, leading to the deterioration of not only the bones themselves but also the muscle and connective tissue that holds the joint together.
While OA typically affects those over the age of 50, genetics, joint injuries, and bone fractures can influence who develops OA and when.
Typical symptoms include joint pain, stiffness, and a loss of flexibility. Once OA develops, there’s typically no going back, with symptoms worsening over time, eventually resulting in chronic pain.
But while there is no cure for OA, many report success in using cannabis-based products to treat joint pain and reduce inflammation. In a North American self-selected survey of 1,483 medical cannabis users, over 95% claimed that cannabis products – either taken orally, applied to the skin, or inhaled – helped in treating their medical conditions including OA. And only one out of three users reported a non-serious side effect.
While there’s plenty of anecdotal evidence and testimonials suggesting that cannabis could be a promising approach for treating OA, the research community is still waiting for medical and clinical studies to back up those claims.
CBD Improves Arthritis Symptoms in Animals
The active ingredient in cannabis most studied for pain management is cannabidiol (CBD). It’s the second most prevalent active ingredient in cannabis, and unlike the more prevalent compound, THC, it does not trigger psychoactive effects. Most laboratory work so far has focused on testing the efficacy and safety of different CBD formulas for treating arthritis in animals.
An international study in 2000, found that CBD blocked the progression of arthritis in mice. On average, mice that received CBD treatments orally had less bone and cartilage damage in their foot joints. The effect was also dose-dependent, meaning higher doses of CBD lead to a more pronounced effect when compared to untreated mice.
In a 2017 study conducted at Dalhousie University, researchers investigated if local injections of CBD could be used to treat rats with advanced end-stage OA. Only 8 rats were examined but when compared to rats who weren’t treated with CBD, both blood work and movement tests showed that CBD reduced inflammation and pain behavior in the animals within 3 hours of treatment.
Researchers also found reduced nerve damage 14 days after the initial CBD dose was administered, suggesting that CBD might be useful in not only managing OA pain and inflammation but also in preventing further joint deterioration.
Researchers at Baylor University found a similar result in dogs. Like humans, dogs can develop OA as they age and experience similar symptoms such as pain and reduced mobility.
Out of the 20 dogs with OA recruited to the study, 9 of the 10 that were fed CBD daily for 4 weeks returned to the clinic with improved mobility and a healthier running gait. Blood work, liver, and kidney tests also came back normal suggesting that the treatment was safe. The improvements lasted for two weeks after their owners stopped administering the CBD medication.
Can CBD Also Improve OA Symptoms in Humans?
Most of the animal studies have been relatively small, looking at cohorts of just 5-20 animals per study. But the evidence that CBD could be a powerful OA treatment option has been mounting.
Current research using human cells and animal tissue suggests that CBD can interact with different types of signal receptors on the neurons in the nervous system. The theory is that when CBD stimulates these neurons, it suppresses the feeling of pain and blocks inflammation. But the drug’s effectiveness and long-term safety in humans are just starting to be studied.
In one randomized placebo-controlled trial, 106 OA patients were asked to apply a CBD gel on their knees twice a day for 12 weeks to see whether the treatment could reduce knee pain. Participants ranked their average daily pain before and after using the CBD gel on a numeric scale from 1 to 10. Researchers also asked patients to report their “worst pain score” and perform a weekly physical function test.
At the end of the 12-week trial, researchers didn’t find a difference in the patients who reported average daily pain between those using the CBD gel and those who weren’t. But they did find that patients reported lower “worst pain scores” and showed improved physical function each week.
Part of the difficulty in assessing the efficacy of CBD in treating OA symptoms in humans is that pain is difficult to measure. Each person’s perception of pain differs and the way pain is remembered and recalled is unreliable. Not to mention an individual’s diet, genetic makeup, and exercise routine can all influence how they respond to treatment.
More rigorously controlled long-term studies are now in the works but until they’re complete, CBD remains a controversial OA treatment option in the scientific community.
A guideline developed by the Arthritis Foundation suggests that all patients consult with the health care provider who treats their OA before trying CBD. CBD has the potential to interact with other common drugs taken by people with OA. Likewise, there are also many types of CBD products and it’s important to choose one that’s safe and of high quality.
So while there are many convincing testimonials advocating for the use of CBD, it’s always best to work with a health care provider to figure out what works best for you.