CBD: What it is, how it's used and what we still don't know

Once a fringe health trend, CBD has become so mainstream that you can buy products with it at pharmacies, grocery stores and countless online retailers. You can largely thank the US Farm Bill for that, which legalized industrial hemp in 2018, allowing CBD products to be sold over the counter across the US. 

CBD has also gained popularity as more states have legalized medical and recreational cannabis products that contain THC, the chemical compound in cannabis responsible for the "high" feeling.

This story discusses substances that are legal in some places but not in others and is for informational purposes only and not for the purpose of providing legal advice. You shouldn't do things that are illegal -- this story does not endorse or encourage illegal drug use.

Depending on where you live, you can find CBD at CVS, your local gas station, pet stores -- even Carl's Jr. The only thing spreading faster than CBD appears to be confusion over what exactly it is and who it's for. Whether you're already a user or are just CBD curious, this primer will help you cut through the misinformation and get up to speed. 

What is CBD?

CBD, or cannabidiol, is a chemical compound from the cannabinoid family that naturally occurs in the cannabis plant. Scientists have isolated 108 different types of cannabinoids in cannabis. 

Delta-9-tetrahydrocannabinol, or THC, is probably the best-known cannabis chemical compound thanks to its psychoactive properties -- but CBD is quickly gaining ground due to its potential therapeutic benefits. 

How does CBD work?

CBD (and THC) work by interacting with our body's endocannabinoid system, a regulatory system made up of naturally occurring cannabis-like molecules. These endocannabinoids, as they're called, work like neurotransmitters, shuttling messages through the body to help maintain homeostasis. Cannabinoids like CBD and THC interact with the endocannabinoid system at two known receptors: CB1 and CB2. 

CB1 receptors are mainly present in the brain -- where they're involved with cognition, memory, motor skills and pain -- but also in the peripheral nervous system, liver, thyroid, uterus and more. THC attaches itself to these receptors, inhibiting the release of neurotransmitters and possibly increasing the release of others, altering normal functioning.

Researchers once thought that CBD did the same thing, but with CB2 receptors -- which are abundant in the immune and gastrointestinal systems, as well as the brain and nervous system. However, they no longer believe that to be true. 

Although the exact way CBD affects our bodies is still unknown, scientists think CBD encourages the body to produce more of its own endocannabinoids, which may help reduce anxiety, pain and inflammation.

Read more: CBD-infused activewear doesn't have science on its side -- yet

Is CBD legal?

Technically yes, but the answer isn't quite so cut and dried. 

The cannabis plant comes in many different varieties. For decades though, the US Drug Enforcement Administration (DEA) treated them all the same, classifying cannabis as a Schedule I substance. Schedule I drugs are considered to have "no currently accepted medical use and a high potential for abuse" and are thus illegal to produce or possess. 

However, the Agriculture Improvement Act of 2018 (aka the Farm Bill) changed all that. The Farm Bill legalized "hemp," which the legislation defined as cannabis that contains no more than 0.3% THC, nationwide. 

Cannabis that contains higher levels of THC is now listed as "marijuana" and remains a Schedule I drug. 

In other words, if a CBD product comes from a hemp plant, it's legal; if it comes from a marijuana plant, it's federally illegal, despite local laws. And even if it does come from a hemp plant, there's often no guarantee it won't contain THC, thanks to things like cross-pollination and the absence of industry regulation (see "What are the risks of taking CBD?" below).

The Food and Drug Administration has been exploring ways to study and regulate CBD for several years now. At this time, no over the counter CBD products are FDA approved or cleared, and there's no nationwide standard for CBD products. However, some states, including Indiana and Utah, require cannabis products to be tested for potency and purity. 

Read more: Can CBD make you fail a drug test?

What are the health benefits of CBD?

CBD is being marketing as a bit of a cure-all, with manufacturers claiming it can do everything from relieving anxiety to stopping the spread of cancer. However, cannabis's classification as a Schedule 1 drug has severely hampered American scientists' ability to study CBD, making it hard to support or refute these claims. The studies that are available tend to be small or are done on animals or in laboratories. 

That said, CBD is showing promise. Early experiments suggest that it may help fight anxiety, ease schizophrenia symptoms and reduce pain (though the latter is often done in conjunction with THC).

The strongest evidence of CBD's effectiveness, though, is in relation to epilepsy. In 2018, the FDA approved Epidiolex, a medication used to treat Lennox-Gastaut and Dravet syndromes, two rare and severe forms of epilepsy. In 2020, it approved Epidiolex to treat seizures related to tuberous sclerosis complex. Epidiolex was the agency's first approval of a cannabis-derived drug, and has paved the way for the development of more CBD-based drugs to treat medical conditions.

How is CBD used?

CBD is available in a variety of forms. Some of the most common CBD delivery methods are listed below, but how it's ultimately used depends on personal needs and preferences. The delivery method of CBD affects how quickly it works and what kinds of effects it has on the body.

• Edibles are broad range of products to eat or drink, like gummies or chocolates. Edibles can take anywhere from 20 minutes to four hours to take effect. 
• Oils and tinctures are processed and concentrated forms of CBD that are often placed under the tongue using a dropper and absorbed into the bloodstream. 
• Pills and capsules are ingested orally and look similar to the vitamins and/or drugs you'd find in a drugstore. They typically contain CBD oil or CBD isolate.
• Topicals are CBD-infused oils, creams and lotions that are intended to be used directly on skin, hair or nails. They're a popular way to treat localized pain, but are also used as skincare, haircare and massage oil as well. 
• Vaping, like e-cigarettes, involves inhaling a vaporized liquid that contains CBD oil. Nicotine is not usually present if CBD is, though it is possible to mix them.
  

What are the risks of taking CBD?

A 2017 World Health Organization report found that CBD, in its pure state, is safe, well-tolerated by humans and animals and not likely to cause physical dependence or abuse. And according to the National Institutes of Health (NIH), 1,500 mg of CBD has been safely taken by mouth daily for up to four weeks. 

That said, there are still a few risks associated with taking CBD that you should be aware of: 

• Side effects. Dry mouth, low blood pressure, lightheadedness and drowsiness have been reported, according to the NIH, as has signs of liver injury, though the latter is less common.
• Limited research. CBD's classification as a Schedule I drug severely limits the amount of studies researchers can conduct on the compound. What does exist is promising, but there are still a lot of unknowns around what conditions CBD could help treat and how much people would need to take for it to be effective. That means if you're taking CBD to treat a particular ailment, you could be taking too much, too little or wasting your money altogether.
• Inadequate regulation. There are no standards in place for producing, testing or labeling CBD products, which makes any type of federal oversight or quality control impossible. In fact, Penn Medicine researchers found that nearly 70 percent of CBD products purchased from the internet contained either more CBD than the label indicated -- which could be dangerous -- or less CBD than was indicated, which could negate any potential benefits. Many products also contained significant amounts of THC. 
• Drug interactions. Not much is known about how CBD could interfere with other medications, but experts say it may interfere with how quickly the body breaks down a variety of prescription medications, which can increase side effects. It can also enhance the sedative properties of herbs and supplements that are known to cause sleepiness or drowsiness. Talk to your doctor or a pharmacist to confirm whether anything you take regularly could be affected by CBD.
• Pre- and post-natal unknowns. There's not yet sufficient evidence about whether it's safe to take CBD while you're pregnant or nursing. Experts advise avoiding it.