Back, foot, and knee aches are among the most common ailments people suffer from, especially once old age sets in. To manage chronic pain, patients have been historically limited to opioids and standard anti-inflammatory meds, each with their own downsides and side effects, including addiction.
Most recently, research suggests that creams and lotions containing cannabidiol (CBD) -- one of the many cannabinoids found in cannabis, which doesn't make you high and could relieve limb pain without the harmful side effects of traditional treatments.
CBD topicals on the rise
Cannabinoids trigger effects in the body by mimicking the endocannabinoids (cannabinoids produced by the body), which play a crucial role in both brain and bodily functions. These substances attach themselves to cannabinoid receptors that are present throughout the body and are associated with detecting pain, appetite, immune function, mood, and more.
The human body has two types of receptors for cannabinoids, called the CB1 receptors and CB2 receptors. Whether it's an annoying itch or a prick of pain, these two receptors on your skin cells will immediately start firing signals to dampen these unpleasant sensations.
CBD lotion and creams bypass CB1 and CB2 receptors and directly stimulate the production of anandamide and 2-AG, neurotransmitters that block signals for pain and itch. What's more, CBD mutes any signal sent to CB1, which is why researchers find the cannabidiol so appealing --this means that they could develop safer pain treatment that won't spark addiction and trigger euphoria like THC does (the other, more famous psychoactive ingredient produced by Cannabis sativa plants).
What's more, CBD interacts with an enzyme called fatty acid amide hydrolase (FAAH), which is responsible for flushing out excess anandamide (a factor in homeostasis) out of circulation. FAAH is known to break down and remove natural endocannabinoids, and CBD stops this breakdown, thereby increasing the endocannabinoids available in the body. Due to endocannabinoids' balancing and healing effects on the body, consuming CBD may produce therapeutic benefits.
Studies on mice suggest that CBD may indeed have therapeutic value against pain and inflammation, with other avenues of therapy still in exploration. For instance, a 2017 study published in the journal Pain found that CBD relieved pain and hindered the development of more pain in rats with osteoarthritis.
Concerning topicals, however, scientists are still working to nail down the proper dose. For instance, the same quantity of CBD topical that brings relief to achy joints may be ineffective for treating nerve damage in the feet.
Nevertheless, the high concentration of cannabinoid receptors in the skin makes CBD topicals highly appealing. Previously, studies found that CBD-infused creams can help manage pain in patients with arthritis and rheumatism. And, in 2019, a study published in the journal Clinical Therapeutics found that CBD ointments improved clinical outcomes for patients with psoriasis, atopic dermatitis, and scarring thanks to its anti-inflammatory properties.
Patients, in turn, seem to be enthralled with CBD. According to a 2019 report from the Arthritis Foundation, 79% of 2,600 respodents who suffer from arthritis said they had considered using CBD or had already used it. What's more, among those who used CBD in the past to treat their arthritis symptoms, 55% said they applied a topical product to their joints.
“I’ll put it on and walk away and think, ‘I don’t have any pain,’” said Eileen Donovan of Ayer, Massachusetts, speaking to U.S. News about how she uses CBD for her arthritis.
However, it's important to note that the effects of CBD on the body may vary from person to person.
The gap between science and anecdotal evidence
Besides dosage, scientists are looking to figure out how much coverage is most effective for rubbing CBD on the skin.
Meanwhile, consumers are purchasing CBD products in increasing numbers and volumes, attract by the prospect of pain and anxiety relief with little symptoms. The problem is that science hasn't had time to catch up to the hype as most studies on CBD haven't actually been carried on humans. Studies on animal models are famous for not always translating to humans, so this is another thing you should consider -- especially if you're taking other medications.
"There's a lot of studies that have been done in animals and those tend to show that it's anti-inflammatory and that it does have some analgesic effect," Kevin Boehnke, Ph.D., research investigator in the department of anesthesiology and the Chronic Pain and Fatigue Research Center at the University of Michigan, told CNET. "Unfortunately they haven't been well translated in humans."
Zynerba Pharmaceuticals performed the only phase two clinical trial that we know of, using a CBD transdermal gel that the company developed in-house. The study involved 320 patients with knee osteoarthritis who received either 250 mg of ZYN002 4.2% CBD gel daily, 500 mg of ZYN002 daily, or a placebo, over 12 weeks. Although the study found some evidence of a reduction in pain and improvements in physical function, scores for measures of pain were not statistically different from placebos.
While the effects of edibles and topical CBD on animals look positive, more scientific research is needed before definitive conclusions can be reached about its effects on humans.
According to Yasmin Hurd, an addiction specialist at the Icahn School of Medicine at Mount Sinai in New York, CBD creams get absorbed into the skin, and from there the product ends up in the bloodstream.
“These are sometimes things people don’t appreciate when they are putting cream ‘only on my knee,’” says Hurd. “We also have a lot of seniors using CBD creams for arthritic pain and we need to know sooner rather than later whether this chemical cream used by so many people can indeed be effective.”
In order to find out more about how effective CBD and other cannabis-derived products are for various ailments, more research definitely needs to be done. For now, CBD is unregulated by the United States' Food and Drug Administration (FDA) and the only CBD-containing product approved by the FDA is a drug for epileptic seizures for patients with Lennox-Gastaut syndrome or Dravet syndrome.