What is CBD oil? Here is everything you need to know

Cannabidiol (CBD for short) is the non-psychoactive component of the cannabis plant. Proponents say it can soothe whatever ails you—from anxiety and arthritis to digestive troubles and even cancer.

What is CBD oil exactly?

CBD—or cannabidiol—is a type of cannabinoid, a family of molecules typically associated with marijuana, but in fact, also found in other plants and even humans (in us, they’re called endocannabinoids). There are hundreds of different cannabinoids in marijuana. The best known is tetrahydrocannabinol, or THC, a chemical in marijuana that targets and binds to certain receptors in the brain to give you a high. CBD is non-psychoactive and non-addictive, and it seems to bind to multiple target sites, thereby affecting a range of systems throughout the body.

How do you use it?

Extracts of CBD—either from marijuana or hemp (a cannabis variant that is essentially free of THC)—are sold as an oil or in tinctures. You can also get CBD via a transdermal patch, capsule, sublingual spray, gel, cream, or vapor. Some contain pure CBD extract (or so they say); others—particularly if you’re in a state where recreational marijuana is not legal—will contain hemp extract, which includes CBD as part of its makeup. As of this reporting, recreational marijuana is legal in nine U.S. states and medical marijuana in 29. Don’t miss these 50 weird things that are banned in the United States.

What is CBD oil used for?

Healthy folks vaguely looking to add a little spring in their step (via better sleep, reducing anxiety, or easing muscle soreness) drizzle a little oil into their smoothie or latte. They might also spot-treat with a dab of oil in problematic areas. In the past several years, published papers have suggested that the compound can help with a spectrum of medical conditions, including anxiety, Alzheimer’s disease, addiction, arthritis, inflammatory bowel disease, fractures, migraines, psoriasis, and pain. In an animal study, purified extracts of CBD and THC appeared to slow the growth of a type of brain tumor.

“Scientists have been studying other constituents in the marijuana plant beside THC, and there has been an emerging interest in the medical community for a while,” says Ryan McLaughlin, PhD, assistant professor of integrative physiology and neuroscience at Washington State University in Pullman.

What is CBD oil going for?

It’s not cheap. A vial containing 500 mg of hemp extract from Mary’s Nutritionals, for instance, costs $110. CBD extract—on its own or as part of a hemp extract, or even with a little THC, if you live in a marijuana-legal state—can be found in a variety of edibles, too, including chocolate bars, honey, and bitters.

“Some products are of little clinical value,” says Joanne Miller, a certified nutritionist at Swanson Health Center in Costa Mesa, CA. “But some can be a total game changer in people’s lives. There are many, many applications.”

Miller, whose clients include patients referred by physicians, uses CBD in a variety of delivery modalities that she has found effective. “Patches can be worn for pain or anxiety management. Capsules or concentrated drops can be taken orally for pain, inflammation, sleep, and anxiety. Balms and creams can be used on the hands and feet to manage arthritic pain. Vaping is another delivery method,” she says.

Her clients require therapeutic doses (generally speaking, 5 to 10 mg per dose), so she recommends brands that have shown results for her clients. Currently, she uses Mary’s Medicinals (available in marijuana-legal states) and Thorne.

How does CBD work?

No one’s really sure: “It’s astonishing that there’s still no real consensus on how CBD works,” says McLaughlin. “One thing we do know is that it doesn’t work through the same receptors as THC, and, in fact, seems to have the opposite effect.” THC mainly binds to a certain type of receptor (known as CB1) in the brain. But with CBD, he says, “there seems to be a lot of complex targets”—which means CBD may affect multiple pathways throughout the body.

From anecdotal evidence in humans and from animal studies, CBD appears to affect the way we experience pain, inflammation, and anxiety. “Scientists have identified a number of receptors in the nervous system where CBD acts,” says Orrin Devinsky, MD, professor of neurology, neurosurgery, and psychiatry at NYU Langone. “It’s established that CBD has anti-inflammatory properties and can increase activity at some serotonin [the feel-good neurotransmitter] receptors.”

What does the science say?

Not much, as far as humans are concerned—at least not yet. The vast majority of studies have been on animals, as of yet, and there are few high-quality studies on humans. Even the oil’s effect on pain—something that CBD oil is popularly used for—isn’t proven. “The studies available are small or not well designed,” says Dr. Devinsky. “There’s a lot of religion out there, but not a lot of data.”

Dr. Devinsky’s research, which was recently published in The New England Journal of Medicine, is beginning to provide that much-needed data in the field of epilepsy research. In a landmark multinational randomized double-blind study for a treatment-resistant form of the condition, subjects taking an oral solution of 20 mg CBD per kilogram of body weight for 14 weeks, along with standard treatment, experienced a 42 percent reduction in drop seizures (the muscles go limp). Those taking a 10 mg CBD per kilogram of body weight saw a 37 percent decrease; patients who got a placebo saw a 17.2 percent decrease. The mechanism hasn’t quite been worked out yet, Dr. Devinsky says, though there’s some evidence that a receptor known as GPR55 may be critical for the anti-seizure effect.

How do I know if it’s really CBD oil in the product?

Unfortunately, you don’t. Even though more than half of all U.S. states now allow marijuana for medicinal purposes—and nine of those, plus Washington DC, allow it for recreational use—the Drug Enforcement Agency still views CBD as a banned substance and therefore doesn’t regulate it (since, in the eyes of the law, CBD shouldn’t be on the market). “I can start a company, put oil in a jar and sell it as CBD oil,” says McLaughlin—and no one has to vouch that what’s in there is for real. You have only the manufacturers word for it.

Should I be wary?

Yes: CBD extracts can’t always be trusted. A 2017 JAMA paper reported that almost 70 percent of all CBD products sold online do not contain the amount of CBD stated on the label. Of the 84 products bought from 31 different companies, 42 percent contained a higher concentration of CBD oil than the label claimed, and 26 percent of the products contained less than the label claimed. The remainder of products contained the labeled amount—give or take 10 percent.

Why are there so many fakes?

"There’s no oversight,” says Marcel Bonn-Miller, PhD, adjunct assistant professor of Psychology in Psychiatry at the University of Pennsylvania and author of the JAMA article. Beyond the label, he adds, “There’s no consistency. You know that every Hershey’s bar you buy and every Coke you buy will be exactly the same. But that’s not the case with the majority of CBD products. It’s not unexpected to see variability within a given brand.” This means that you may notice improvements the first time you buy and try a particular product, but none the next.

“There’s no way to know what you’re getting unless you bring the product yourself to a reputable lab and get it analyzed,” says Bonn-Miller.

Are there side effects to CBD oil?

As Dr. Devinsky points out in his research, side effects, at least in therapeutic doses, can include fatigue, diarrhea, and weight loss, just to name a few.

On its own, CBD is pretty safe; the side effects tend to come from the things it’s mixed with (which may or may not be on the label). “CBD is not the only ingredient in CBD extracts. They can have THC as well, sometimes in decent amounts,” says Bonn-Miller, “and that’s where it can get more complicated.”

THC-dominant edibles (like chocolates) can carry an even higher risk. “It can take one or two hours to feel an effect from ingestion as opposed to a few seconds from inhalation,” says Dr. Bonn-Miller. “This makes titration very difficult.” Add to that, an edible is made to taste good. So you can easily eat more than you should in the course of a few minutes—and end up feeling negative effects hours later.

What’s the best way to try some?

The Internet is lousy with the stuff, but for a safe and reliable source, talk to your physician, advises McLaughlin. She may be able to introduce you to a reputable practitioner who can offer CBD oils and related therapies—or she may know of a colleague who can make a referral. If you’re trying to treat a medical condition, it’s better to avoid the guesswork and find guidance from a practitioner who’s had experience in—and is knowledgeable about—the most reliable CBD products and doses for your condition. Here are 14 things you should never lie to your doctor about.