CBD: Does it work? Is it safe? Is it legal?
Cannabidiol has been used to treat insomnia, depression, anxiety, and more. But what does the science say about its safety and efficacy? And do consumers have to worry about getting into legal trouble for using marijuana’s cousin?
Cannabidiol — better known as CBD — seems to be everywhere: in gummies, lotions, oils, lollipops, vapes, toothpaste, even a high-end sports bra. It’s been touted as a treatment for such concerns as anxiety, insomnia, pain, PTSD, and depression.
And it’s increasingly popular. Last year, 64% of U.S. adults reported trying a CBD product — and nearly half of those did so at a doctor’s suggestion, according to a Forbes Health survey. In 2022, the CBD market was valued at $18 billion, and it’s expected to more than triple in the next 10 years.
But hype aside, researchers are hard at work assessing the true value of CBD — which comes from the same plant family as marijuana but doesn’t induce a high — and the varied products it has spawned.
Here’s what experts have to say about CBD’s risks and benefits — and where they see CBD use headed in the future.
Does CBD work?
The medication Epidiolex — the only CBD-based treatment approved by the U.S. Food and Drug Administration (FDA) — has been proven effective for severe seizure disorders. A twice-daily oral solution, Epidiolex has been shown to be effective in a number of clinical trials, including a 2021 study that found a median decrease in certain seizures ranging from nearly 50% to over 70%.
But some research suggests CBD also holds promise for treating various other concerns and conditions.
Anxiety. A handful of studies suggest a possible role for CBD in addressing social anxiety, including one in which individuals treated 90 minutes before a public speaking exercise felt less stressed than placebo-receiving peers. There are some indications that CBD may also help with anxiety generally, but studies on that have various limitations. For example, one longer-term observational study yielded a somewhat complicated outcome: Individuals with moderate to severe anxiety experienced improvement, but those with milder anxiety became slightly more anxious. Among the most promising studies is a 2022 Nature publication reporting that people with moderate to severe anxiety experienced a 60% to 70% reduction in symptoms after four weeks of treatment with a high-CBD-content product. Those individuals knew they were receiving CBD, though, so a blinded randomized controlled trial (RCT) is underway to confirm the earlier findings.
Sleep. Published case reports and uncontrolled clinical trials suggest the potential of using CBD products for better sleep. In one unblinded study of 23 patients with epilepsy, 85% of those treated daily for three months with CBD showed an improvement in sleep. However, the handful of RCTs to date studying sleep for people without epilepsy are inconclusive. One study of healthy volunteers found no effect of a single dose of CBD while another, of people with insomnia, found better self-reported sleep after one dose.
Pain. Studies of CBD administered orally for pain have yielded mixed findings — though they did not explore the efficacy of high doses. Topical CBD looks more promising. In one 2020 study of patients with peripheral neuropathy, those given a topical CBD oil experienced a significant reduction in sharp pain and cold, itchy sensations compared to those who received a placebo.
Addictions. CBD shows promise for reducing drug cravings for patients with opioid use disorder. In one study, former heroin users who received CBD had a two- to three-fold decrease in cravings compared to those receiving a placebo. That study was fairly small, but researchers are working to replicate results with a larger cohort. In addition, early research suggests CBD may hold some hope for treating alcohol use disorder. Tobacco-related results are mixed.
Meanwhile, some experts remain cautious about CBD, pending further studies.
“It’s premature to say CBD is effective for any specific medical condition. Currently, there’s very little evidence proving effectiveness for conditions other than some pediatric seizures,” says Igor Koturbash, MD, PhD, co-director of the Center for Dietary Supplements Research at the University of Arkansas for Medical Sciences in Little Rock. More compelling evidence would require RCTs that compare high-quality CBD to a placebo, he adds.
Extensive CBD research is underway. In fact, researchers are conducting nearly 200 clinical trialsrelated to CBD, examining its effectiveness to treat PTSD, cancer, schizophrenia, cognitive impairment, ADHD, Parkinson’s disease, and other conditions.
“In the next few years, we hope to have concrete information about the best dosing protocols for specific symptoms and conditions. That’s critical for efficacy,” says Yasmin Hurd, PhD, a CBD researcher and director of the Addiction Institute of Mount Sinai Hospital in New York.
Is CBD safe?
A 2018 World Health Organization report called CBD “generally well-tolerated, with a good safety profile.” It also found that CBD was not addictive.
“CBD doesn’t seem to change people’s respiration or other vital signs, and it doesn’t appear to make them sedated or high,” says Shanna Babalonis, PhD, a University of Kentucky College of Medicine behavioral science associate professor and contributor to the report.
In clinical trials for Epidiolex, many research participants reported relatively mild side effects, such as fatigue and digestive issues.
Still, CBD raises certain safety concerns.
For example, research on mice suggests possible harm to the male reproductive system. Another concern comes from human trials for Epidiolex, which found that high doses of CBD were associated with signs of liver damage in a small number of study participants. The liver risks increased when CBD was combined with certain other medications.
Taking CBD together with other medications or substances may trigger additional interactions. CBD may amp up the impact of caffeine, for example, says Tory Spindle, PhD, a cannabis researcher and associate professor of psychiatry and behavioral science at Johns Hopkins Medicine in Baltimore.
Experts also note the limited research on CBD thus far. Unknowns include whether CBD raises concerns for specific populations like elderly individuals or pregnant people.
And little is known about long-term use of the substance. That’s in part because CBD-related research in the United States was tightly restricted until 2018, when the U.S. Farm Bill made hemp, which yields CBD, legal.
But all these concerns seem minor compared to a far greater CBD-related worry, experts say.
Existing research comes from trials conducted using high-quality CBD — but the commercial CBD market “is an entirely different beast,” says Babalonis. “The CBD administered in research trials is not comparable to what you get at the gas station or online. You can’t necessarily even call some of the unregulated products CBD.”
Babalonis and others have tested CBD products to see if their labels accurately convey their content. In one study of hemp oil products, researchers found a mismatch between claimed and actual CBD levels in 22 out of 25 of them.
“The CBD administered in research trials is not comparable to what you get at the gas station or online. You can’t necessarily even call some of the unregulated products CBD.”
Shanna Babalonis, PhD
University of Kentucky College of Medicine
Even more disturbing is the presence of substances not listed on the label. Those can include dangerous heavy metals and significant doses of THC (tetrahydrocannabinol) — the compound in marijuana that induces a high.
“We even analyzed products that specifically said, ‘THC-free,’ and several of them in fact were not,” says Babalonis. Among other concerns, THC contamination can cause an individual to fail a drug test.
Spindle echoes concerns about the CBD market. “I don’t trust it. That doesn’t mean there aren’t big players who manufacture products using better standards,” he says. “It’s just that generally speaking, it’s the Wild West.”
Is CBD legal?
Understanding CBD’s legality takes understanding a bit about the cannabis sativa plant family. Both marijuana and hemp belong to the family, but marijuana contains much more THC than CBD, and the reverse is true for hemp. Because hemp tends to have a lower THC content, Congress made it legal in 2018 — as long as it has .3% or less of THC using a dry weight measure.
At the state level, laws regarding CBD use vary, though, with some making use fully legal and others putting restrictions on it. Still, experts say prosecution is unlikely as long as users don’t buy CBD products that also contain levels of THC that exceed the federal limit. “You’re not going to face legal action for buying CBD products if you don’t break the federal law,” says Koturbash.
Because CBD is FDA-approved as a medication (Epidiolex) it cannot be legally added to food or sold as a dietary supplement — unless the FDA specifically determines that it’s safe to do so, a step it has not taken.
Why, then, are so many CBD products available? To some extent it’s because limited resources prevent the FDA from doing much more than issuing warning letters to companies. In the past five years, the agency has done so about 100 times.
Meanwhile, industry groups have requested FDA rules that would allow CBD to be sold legally. In January, the agency rejected the request, indicating that CBD did not meet applicable safety standards under current law. Instead, the FDA advised the creation of a brand-new regulatory pathway that could include safeguards such as a minimum legal purchase age. But creating such a pathway would require an act of Congress — something unlikely to happen soon.
Experts say they can understand the FDA’s reluctance to oversee CBD under current circumstances.
“From my understanding, there have never been any prescription medications that have also been sold simultaneously in food and drink or as supplements,” says Babalonis. “This situation is rather unprecedented.”
What CBD-related words of wisdom do experts offer?
Despite the various downsides, the public obviously is drawn to CBD. So, is there anything consumers can do to reduce potential CBD risks?
“Unfortunately, people need to do a lot of their own homework to check out companies and products,” says Hurd. “Some companies have their products tested by an outside third party to assess aspects of safety, including whether it’s free of contaminants, so that can be helpful.”
One option is checking out a product’s lab-generated certificate of analysis (COA), says Staci Gruber, PhD, who spearheads a project at McLean Hospital in Belmont, Massachusetts, dedicated to examining medical cannabis and CBD use.
“Higher-level vendors will have a COA on their website, which will tell you the makeup of the product. And if manufacturers say they do their own analysis instead of using an outside lab, walk away.”
Some researchers advise simply avoiding the commercial market.
Koturbash suggests looking for a registered clinical study. “You’ll know the quality of the product and the dose you’re receiving, and they’ll monitor you carefully to ensure your safety,” he says.
Another option is purchasing CBD at a cannabis dispensary, since products there always need to meet state regulatory standards, says Spindle. Still, he adds a piece of dosing wisdom: “Start low and go slow.” That’s because CBD products can have a touch of THC in them — and even a little can affect some people, such as novice users.
“I want to know what patients are going through that makes them seek CBD, and I want to have compassion for them. They obviously are suffering and seeking a solution.”
Smita Das, MD, PhD
American Psychiatric Association
Whatever CBD products consumers use, they should keep their doctors in the loop, experts emphasize.
“I so appreciate the opportunity to have conversations with patients because CBD can interact with other medications they’re taking,” says Smita Das, MD, PhD, chair of the Council on Addiction Psychiatry at the American Psychiatric Association.
Das adds another reason she values those conversations.
“I want to know what patients are going through that makes them seek CBD, and I want to have compassion for them. They obviously are suffering and seeking a solution.” Still, she would discourage using CBD to treat mental health conditions. “We have so many evidence-based treatments that have been studied for decades and proven safe. I would absolutely encourage using those instead.”