CBD vs. THC. Understand the differences.


You’re not imagining things—the CBD vs. THC debate is all over the place. That’s because cannabis, once a highly stigmatized substance, is now something at least one out of every 10 of your coworkers is probably using.

Three decades ago, 81% of Americans believed that all cannabis use should be illegal. Now the picture has flipped and 91% of adults in the US believe it should be legal, while 12% report using it regularly

The mainstreaming of cannabis means much less stigma, but it also means that consumer education is more important than ever before. Two products on the same dispensary shelf can have drastically different effects, and you need to understand why before you choose the right product for your needs.

It all comes down to THC and CBD, the most popular members of a chemical family known as the cannabinoids.

What Are Cannabinoids?

Cannabinoids, technically known as phytocannabinoids (phyto meaning plant) are naturally abundant in the cannabis plant. Differentiating phytocannabinoids, although it sounds like it would be a complicated and possibly painful process, is a simple but important step in understanding why THC and CBD are different.

Chemically, THC and CBD are almost identical cannabinoids with the same number of carbon, hydrogen, and oxygen atoms. There’s just one difference, namely the placement of a single hydrogen atom:


That one little “H” atom explains why weed gets you high, but your CBD cream doesn’t.

Cannabinoids and You

This is where endocannabinoids re-enter the picture. These are the chemicals that look and behave a lot like THC and CBD, but they come from your own body. Even if you’ve never used cannabis before, your body produces cannabinoids and sends them to bind with endocannabinoid receptors. 

Receptors are tiny communication hubs in the body. They wait for perfectly-fitting chemicals to come along and attach to them. When that attachment happens, it triggers a particular chemical reaction.

Endocannabinoid receptors fit your body’s cannabinoid chemicals like gloves. The interesting part is that when THC and CBD get into your body, because they look and act so much like your native endocannabinoids, they bind to those same receptors.

That’s not the whole story, though. Remember that one hydrogen molecule? It means that THC can bind to receptors that CBD won’t fit, and that means they cause different chemical reactions.

Mechanisms of Action for Cannabinoids

For decades, scientists debated why cannabinoids in plants could affect the human body as strongly as they do. Then, in the late 1980s, scientists finally pinpointed a site on endocannabinoid receptors where they bound to their matching chemicals. 

By 1993, researchers had identified two different receptors, which they called CB1 and CB2. They explained everything about how THC and CBD work in the body. 

There are two important differences to understand when you’re figuring out the CBD vs THC distinction:

  • THC can bind to the CB1 receptor, but CBD can’t.
  • There are CB1 receptors in the brain regions responsible for higher-order thinking.

When THC binds to those brain CB1 receptors, it can create a powerful euphoric effect. In other words, it gets you high.

CBD can’t bind to CB1 receptors, so it can’t get you high. In fact, when your cannabis product contains a higher concentration of CBD versus THC, the CBD can get in the way of THC’s attachment to those receptors in the brain. The result is a less intense, mellower high. 

Beyond the High: Medicinal Effects of CBD and THC

So that’s the “getting high” component of the CBD vs THC discussion, but there’s a lot more to the story. The rest has to do with the medicinal effects of the two chemicals, CBD in particular. 

What Are the Medical Benefits of CBD?

People turn to CBD for a lot of different reasons, from anxiety and depression to chronic pain and arthritis. Studies continue to pile up and provide evidence that CBD can help with these issues, but official government approval and regulation has been slow in coming. 

So far, there’s only one FDA-approved drug that comes from CBD, and that’s Epidiolex. Epidiolex got its approval in 2018 to treat Dravet syndrome and Lennox-Gastaut syndrome, two extremely severe childhood seizure disorders.

There are numerous stories out there of how Epidiolex, and CBD in general, have dramatically changed life for children and adults with epilepsy. Some, like 18-year-old Jon, have been able to fill Epidiolex prescriptions and see dramatic improvement quickly. 

Other families have had to struggle and even move across state lines to get their hands on the CBD that helps their children. For parents like Matt Wetzel, though, the struggle has been well worth it. Thanks to CBD, Matt’s 7-year-old son, Jameson, is now seizure-free.

What Are the Medical Benefits of THC?

THC is less well-known than CBD as a symptom reliever, but THC is no slouch either. It can relieve many of the same symptoms as CBD, including pain and inflammation. It also helps to relieve nausea, appetite loss, and insomnia—three benefits that make it popular with cancer patients going through chemotherapy.

For many people, CBD and THC in combination give the best symptom relief. That’s because when the two chemicals are in your body, they give each other a chemical boost so that when they do bind to your endocannabinoid receptors, they do their job even more effectively.

What Are the Side Effects of CBD and THC?

This might be the best part—all of these benefits from cannabis, and there are minimal to no side effects. According to the World Health Organization, CBD has no serious side effects, other than those related to interactions with other drugs.

THC can have some mild side effects, including:

  • Red eyes
  • Dry mouth
  • Racing heart
  • Reduced reaction time

In adults, these side effects are temporary and will typically wear off. Teenagers may experience longer-term impacts on brain development, and that’s why recreational cannabis is illegal for minors in the US. Even if it’s legal in your state, you have to be 21 or older to take advantage.

CBD vs. THC: What Are the Laws, Exactly? 

CBD, THC, and law have a complicated relationship in the United States. Not all cannabinoid products are created equal, and whether one is legal depends on where it comes from, what it contains, and where you are. 

The first thing you should know is that CBD and THC products come from two different types of cannabis plants: marijuana and hemp.

Marijuana vs. Hemp: What’s the Difference and Why Does It Matter?

Hemp doesn’t contain much THC because it’s not cultivated as a drug plant—it’s an industrial crop. Its fibers are used in a myriad of products including paper, clothing, food, and even building materials. Hemp is also a popular source for extracting hemp, as evidenced by the “hemp-derived CBD” label on many topicals, edibles, oils, and more. 

Not all CBD products are hemp-derived, though. Some come from the marijuana plant, which is also the source plant for any cannabis products that contain significant amounts of THC. Marijuana, which some refer to simply as cannabis, is grown specifically for the psychoactive and medicinal properties of the cannabinoids it contains.

Marijuana vs. Hemp: The Legal Issues

In the United States, hemp is considered industrial as long as it contains less than 0.3% THC. Growing this kind of hemp is legal in most states, and so is selling products extracted from it. 


Anything made from marijuana plants, on the other hand, is illegal at the federal level in the US. Some states allow people to make, use, and sell CBD and THC products made from marijuana, and even more allow it for medicinal purposes only. 

Either way, though, you have to keep all related activity within state lines. You’re not even allowed to cross state borders with it.

There’s just as much variation in cannabis law beyond US borders. If you plan to travel, check local laws before seeking out any CBD or THC products, and don’t bring any with you when you fly.

Can you fail a drug test?

It’s very rare for a drug test to screen for CBD since it’s not considered to be a regulated drug. Some tests do screen for THC, though, and if your CBD supplement has a high enough concentration of THC, you may get flagged.

That can be a big problem for people who take CBD for medical reasons—people like the New Mexico police officer who was taking CBD hemp oil for pain and lost his job after he failed a drug test

When things like this happen, it’s usually because the CBD product is inaccurately labeled. If you have a job that does drug testing, make sure what you’re taking has been third-party tested and has an accurate THC measure.

In Conclusion

It’s ironic, really—CBD and THC are the same except for one tiny atom, but that one atom changes everything. It means that THC can get you high while CBD can’t.

That difference explains why hemp is legal where marijuana isn’t. It explains why people seek out CBD-specific supplements for medicinal benefits, and why drug testers look for THC but not CBD.

What are your thoughts on CBD vs. THC? Do you seek out one versus the other? What are you looking for when you’re shopping for cannabis products? Leave a comment below and let’s keep the conversation going.