As marijuana is legalized in more and more states, the wellness world has whipped itself into a frenzy over a non-intoxicating cannabis derivative called cannabidiol. CBD products can be found on the internet and in health-food stores, wellness catalogs and even bookstores. (A bookstore in downtown Boulder, Colorado, displays a case of CBD products between the cash register and the stacks of new releases.) Celebrities like Gwyneth Paltrow, disgraced cyclist1 Floyd Landis and former Denver Broncos quarterback Jake Plummer are all touting CBD products, and according to Bon Appétit, CBD-infused lattes have become “the wellness world’s new favorite drink.”
But, uh, what is it that CBD is supposed to do? I visited a cannabis dispensary in Boulder to find out what the hype was all about. After passing an ID check, I was introduced to a “budtender” who pointed me to an impressive array of CBD products — tinctures, skin patches, drink powders, candies, salves, massage oil, lotions, “sexy time personal intimacy oil” and even vaginal suppositories to treat menstrual cramps.
Most of these products promised to relieve pain or otherwise enhance well-being, and none of it was cheap. (Prices started at about $30.) But I wanted to know: Does any of this stuff really work? After a deep dive into the scientific research, I learned that the answer was a big fat maybe.
Although there’s enticing evidence that good ol’ cannabis can ease chronic pain and possibly treat some medical conditions, whether CBD alone can deliver the same benefits remains an open question. What is clear, at this point, is that the marketing has gotten way ahead of the science.
Cannabinoids are a class of compounds that interact with receptors throughout your body. CBD is just one of dozens of cannabinoids found in cannabis, including tetrahydrocannabinol (THC), which is the one responsible for marijuana’s famous high. Medical cannabis is technically any cannabis product used for medicinal purposes, and these can contain THC or CBD or both, said Nick Jikomes, a neuroscientist at Leafly, a website that provides information about legal cannabis. “A common mistake people make is to think that CBD is ‘the medical cannabinoid’ and THC is ‘the recreational cannabinoid.’” That’s inaccurate, he said, because THC is a potent anti-inflammatory and can be helpful for pain.
What makes CBD so appealing is that it’s non-intoxicating, so it won’t get you high, though it “is technically psychoactive, because it can influence things like anxiety,” Jikomes said. Although much of the marketing blitz around CBD centers on the fact that you can take it without getting stoned, there isn’t much research looking at the effects of CBD when used in isolation, with a couple of exceptions. One is the use of CBD to treat seizures: CBD is the active ingredient in the only cannabis product that the Food and Drug Administration has signed off on — a drug called Epidiolex, which is approved for treating two rare forms of epilepsy. Animal models and a few human studies suggest that CBD can help with anxiety, but those are the only conditions with much research on CBD in isolation.
Last year, the National Academies of Sciences, Engineering and Medicine released a nearly 500-page report on the health effects of cannabis and cannabinoids. A committee of 16 experts from a variety of scientific and medical fields analyzed the available evidence — more than 10,000 scientific abstracts in all. Because so few studies examine the effects of CBD on its own, the panel did not issue any findings about CBD specifically, but it did reach some conclusions about cannabis and cannabinoids more generally. The researchers determined that there is “conclusive or substantial evidence” supporting the use of cannabis or cannabinoids for chronic pain in adults, multiple sclerosis-related spasticity (a kind of stiffness and muscle spasms), and chemotherapy-induced nausea and vomiting. The committee also found “moderate” evidence that cannabis or cannabinoids can reduce sleep disturbances in people with obstructive sleep apnea, fibromyalgia, chronic pain and multiple sclerosis, as well as “limited” evidence that these substances can improve symptoms of Tourette’s syndrome, increase appetite and stem weight loss in people with HIV/AIDs, and improve symptoms of PTSD and anxiety.
Donald Abrams was a member of the committee that reviewed the evidence that went into producing the report, and he said that the studies they reviewed overwhelmingly used pharmaceutically available preparations that contain THC, including dronabinol, nabilone and the whole-plant extract spray nabiximols, which contains equal parts CBD and THC. It’s impossible to know whether the benefits of cannabis can also be obtained from CBD alone, Abrams said, because CBD is just one of 400 chemicals present in the plant. So far, CBD in isolation has been studied in only a handful of randomized, placebo-controlled trials (considered the gold standard of evidence in medical research), and the evidence remains sparse.
Still, as the saying goes, absence of evidence isn’t necessarily evidence of absence, and there’s a reason we don’t have a ton of solid research on CBDs yet — “to study it, we need a good source, ” said Ziva Cooper, who is an associate professor at Columbia University and was on the National Academies committee. CBD is hard to get because it’s still technically a Schedule I drug, which limits its availability, Cooper said.
Cooper recently got funding from the National Institutes of Health for a study looking at cannabinoids — including CBD in isolation — as a substitute for opioids, and numerous other clinical trials of CBD are underway. It will be several years before results are available, but these studies should help clarify both what benefits the substance may provide and any side effects it may come with. Most of the adverse effects so far associated with cannabis, such as impairments in short-term memory, coordination and judgment,2 come from products that contain THC as well as CBD, Cooper said, but we need to do more studies to find out for sure whether CBD has fewer risks. Studies are also needed to identify the best way to administer and dose CBD. “I get emails from people asking me what dose of CBD to use, and the truth is, we really don’t know,” Cooper said.
In the meantime, some physicians are forging ahead — and cashing in. Joe Cohen is a doctor at Holos Health, a medical marijuana clinic in Boulder. I asked him what CBD is good for, and he read me a long list of conditions: pain, inflammation, nausea, vomiting, intestinal cramping, anxiety, psychosis, muscle spasms, hyperactive immune systems, nervous system degeneration, elevated blood sugar and more. He also claimed that CBD has anti-cancer properties and can regenerate brain cells and reduce the brain’s levels of amyloid beta — a kind of protein that’s been linked to Alzheimer’s disease. I asked for references, noting that most of these weren’t listed in the Academies report or a similar review published in the Journal of the American Medical Association. “I think you just have to Google search it,” he said. It’s true that a preliminary study found hints that cannabinoids might reduce beta amyloid proteins in human brain cells, but the study was done in cells grown in a lab, not in people. As for cancer, the FDA sent warning letters last year to four companies that were selling products that claimed to “prevent, diagnose, treat or cure” cancer.
Those warning letters aside, there’s not a lot of federal oversight right now over the claims being made or the products that are being sold. Cohen warned against buying CBD products online, because “there’s a lot of scams out there.” Yet his clinic sells CBD, and he admits, “I say ‘Don’t buy online,’ but ours is worth doing, because we know what we’re doing. We ship all over.”
Right now, there’s a good chance that you don’t really know what you’re getting from any source. Testing and labeling rules vary by state, but many states that allow legal cannabis also require some kind of testing to verify that the THC and CBD levels listed on the label are accurate. However, this testing is controversial, and results can vary widely between labs, Jikomes said. A study published in March found measurable variations in test results, with some labs consistently reporting higher or lower levels of cannabinoids than others. There are no guarantees that the label accurately reflects what’s in the product. For a 2015 study published in JAMA, researchers tested 75 products purchased in San Francisco, Los Angeles and Seattle and found that only 17 percent were accurately labeled. More than half of the products contained significantly lower levels of cannabinoids than the label promised, and some of them contained only negligible amounts of the compounds. “We need to come up with ways to confidently verify the composition of cannabis products and make this information available to consumers,” Jikomes said.
“All these people are making claims,” Abrams said, but right now, there’s little verification. “It’s the Wild West.”
Christie Aschwanden is FiveThirtyEight’s lead writer for science. Her book “Good to Go: What the Athlete in All of Us Can Learn from the Strange Science of Recovery” is available here. @cragcrest