What's the difference between THC and CBD? From their effects and medical uses to the way they affect drug tests, these two cannabinoids have very unique personalities.

With its psychoactive effects, THC (tetrahydrocannabinol) has long been famous as the power behind marijuana’s signature high. In recent years, CBD (cannabidiol) has dominated the headlines and internet due to its health benefits and nonintoxicating effects. For those who are considering CBD vs THC for an ailment or medical issue, it’s important to learn about the difference between the two.

The differences are pretty significant, especially given that THC and CBD are both ingredients of the same plant. From how they work within the body to their side effects and health benefits, having a full understanding of both compounds will help ensure that they’re used appropriately.

CBD vs THC: The Similarities

One of the reasons people get confused about CBD and THC is because they share a few things in common. They both come from cannabis, are created in a similar chemical fashion, and can be ingested in the same ways. Here are a few commonalities between the two compounds.

They’re Both Cannabinoids

Some of the confusion people experience with CBD and THC is that they’re both phytocannabinoids. This means that they’re plant-based cannabinoids, or active ingredients in the cannabis plant. The cannabinoids in marijuana are what create all of its side effects, from a hazy euphoria and dry mouth to increased appetite and pain relief.

While these ingredients are what recreational marijuana users rely on to get high, they’re also at the heart of marijuana’s health benefits. Together with the other cannabinoids, THC and CBD are what makes marijuana a promising medical treatment for a variety of conditions.

Both Come from CBGA

Another similarity shared by CBD and THC are that they both start out as the same cannabinoid. Initially, young marijuana plants are very high in CBGA, or cannabigerolic acid. CBGA is the precursor to CBG, but due to an enzymatic reaction that occurs in the glandular trichomes of the plant, it can also turn into THCA, CBDA, and CBCA.

These cannabinoids lose the “A’s” at the end of their names and are transformed from their acidic forms into THC, CBD, and so forth when exposed to heat (and to a small degree, when exposed to light). Once this happens, the effects of the cannabinoids have been activated.

Shared Ingestion Methods

When thinking about THC vs CBD and their similarities and differences, ingestion methods is another aspect they share in common.

Ingestion methods for both THC and CBD include:


Most strains of marijuana have significant levels of THC, but dispensaries also sell high-CBD strains (particularly for medical patients).


Cannabis consumers can also vape THC and CBD, either by using a vaporizer designed for dry marijuana bud or by vaping oil that’s rich in either (or both) of these cannabinoids.

Edible consumption

For years, marijuana consumers have used dry herb to create a large menu of THC-infused treats from cannabutter to baked goods such as brownies. People can also consume CBD and THC orally in products made with concentrations of the compounds (these include oils and tinctures that can be made into drops, sprays, etc.).


Creams and lotions containing THC/CBD can interact with cannabinoid and other receptors located throughout the body. This provides effects such as pain relief without creating any sort of high.

CBD vs THC: The Differences

When researching CBD vs THC, their differences become apparent rather quickly. Although the compounds evolve from the same cannabinoid and they can be ingested in similar ways, they are different in everything from their method of action to many of their effects.

How They Work

THC plugs neatly into the body’s CB1 and CB2 receptors, which is how it makes people high and kills pain. CBD doesn’t bind as well with these two receptors, which is one of the reasons it fails to produce a high. Instead, CBD increases the amount of natural endocannabinoids present in the body. These chemicals do things such as relieve pain, create relaxation, and alleviate anxiety.

Effect on the Brain/Body

CBD and THC are also quite different in terms of their effects. Although the two originate from the same cannabinoid, in their final forms, they affect the body in very different ways. While both compounds can create relaxation, drowsiness, and act as pain relievers, THC is known for causing a euphoric high. Meanwhile, CBD leaves people feeling clear-headed. This is due to the fact that they interact with different groups of receptors in the brain and throughout the body.

Presence in Drug Tests

One of the biggest worries people have when looking into THC vs CBD is whether the compounds will cause them to fail a drug test. Drug screening tests look for the presence of THC, so consuming anything with THC (via vaping, smoking, or edibles) is likely to cause a positive test result over the following few weeks.

While CBD by itself won’t cause someone to fail a drug test, CBD oil derived from marijuana (often found in legal states) frequently contains a certain amount of THC. If the THC levels in CBD oil are high enough, it could show up via drug testing.

Presence in Hemp vs Marijuana

What’s the difference between THC and CBD when it comes to marijuana and hemp? While both plants come from the cannabis genus of plants, marijuana is the only one of the pair that generates significant amounts of THC. The levels of THC in hemp are typically 0.3% or less. This isn’t enough to cause side effects or show up on a drug test.

Meanwhile, CBD can be found in both marijuana and hemp. It’s found in varying amounts in many recreational strains, and breeders have been working hard to create high-CBD strains of marijuana for medical users. CBD is also plentiful in hemp. While hemp-derived CBD can be an excellent alternative for those who live in states without legal access to marijuana, some medical cannabis proponents believe that CBD from marijuana works better because it features the full range of marijuana cannabinoids, terpenes, and other compounds.

Medical Benefits of THC vs CBD

The medical differences between CBD and THC are significant, as well. While they can both be used to treat some of the same symptoms (pain, nausea, and insomnia) and are showing promise in their ability to fight cancer cells, there are certain diseases for which one is a better treatment than the other.


While some tout THC as being good for their anxiety, the fact is that in many people, THC can cause or worsen feelings of anxiousness. Meanwhile, CBD can counteract these effects from THC – but it also works as an effective anti-anxiety treatment on its own. This has led many people to opt for daily doses of CBD in favor of traditional pharmaceuticals that often leave them feeling tired, zombielike, and unable to feel or function.


Marijuana has long been used as an alternative to prescription glaucoma medications, and this is because THC is excellent at lowering intraocular pressure. Doctors still prefer traditional glaucoma treatments over cannabis due to concerns about THC causing low blood pressure within the eye, potentially decreasing the blood supply and damaging the optic nerve. With its painkilling properties, THC is still a popular choice for late-stage glaucoma patients seeking relief.


Due to its anti-seizure activity, CBD has shown to be effective for certain forms of epilepsy. It’s so effective, in fact, that pharmaceutical companies have begun purifying and concentrating CBD from marijuana plants. Sold as Epidiolex, this whole-plant version of CBD is being prescribed to treat rare forms of epilepsy such as Dravet syndrome and Lennox-Gastaut syndrome.


Another area where CBD and THC part ways in the field of medical treatment is in people with psychotic disorders. Numerous studies have found that THC may increase the risk of developing schizophrenia or trigger symptoms in those who have already been diagnosed. Meanwhile, CBD’s antipsychotic effects make it a potentially effective treatment for people with schizophrenia.


Tremors and muscle spasms are common symptoms that plague people with multiple sclerosis, and THC has been proven effective at reducing both. This raises the possibility of THC as an alternative to traditional pharmaceutical treatments for MS. Research shows that CBD helps reduce spasms, but not tremors.

THC and CBD in Pharmaceutical Medicine

Because so many studies have shown positive results, the pharmaceutical industry has worked to find ways to turn marijuana into prescription medicine. Just like whole-plant marijuana, these treatments aren’t one-size-fits-all. Specific marijuana-derived medications use either synthetic cannabinoids or concentrated and purified cannabinoids derived from the whole plant. Once they’re given FDA approval, they can legally be prescribed to patients everywhere and are eligible for coverage under health insurance (while medical marijuana is not).

THC-Based Medications

Dronabinol (marketed as Marinol) made waves in the medical world as the first THC-based pharmaceutical. A synthetic form of tetrahydrocannabinol, dronabinol has been approved to treat people with nausea, vomiting, and low appetite due to chemotherapy or AIDS.

CBD-Based Medications

In 2018, the FDA approved Epidiolex, a concentrated and purified form of CBD, to be used for patients with rare forms of epilepsy (such as Dravet syndrome). Epidiolex is the first whole-plant CBD-centric medication to gain FDA approval. The DEA reclassified Epidiolex from a Schedule I drug to a less-restrictive Schedule V. Meanwhile, CBD itself remains classified as a Schedule I substance (along with drugs like cocaine and heroin).


Nabiximols (Sativex) is an oral spray that contains a 1:1 ratio of whole-plant THC and CBD. It’s approved for treatment of muscle spasticity due to multiple sclerosis, as well as cancer pain and neuropathic pain in people with MS.

Combining Cannabinoids

A common assumption people make when learning about CBD vs THC is thinking that the two are better when concentrated and used separately. This can create some rather powerful effects, whether the product is a THC tincture or an oil with a high percentage of CBD.

As effective as the two are when used individually, there’s a growing theory that to get the most out of CBD and THC, it’s best to combine them.

The Entourage Effect

For years, many patients have insisted that they got greater relief from simply smoking marijuana than from taking THC as a natural concentrate or pharmaceutical synthetic form. One of the reasons for this is that the effects of concentrated THC (natural or synthetic) can be powerful and dizzying. Another reason is that other cannabinoids such as CBD work to counteract common THC effects that many medical patients don’t want (the intense high, anxiety, or increased heart rate).

Scientific studies have been confirming much of the anecdotal evidence from patients. It seems that far from being incompatible, these contrasting cannabinoids often work best when used as a pair. In addition to CBD smoothing out the unwanted effects of THC, research suggests that the whole spectrum of cannabinoids may function to help individual ones work even better. This is because they all work on different receptors in the brain and body, with some paving the way for others to work more effectively.

CBD-to-THC Ratio

Armed with this knowledge, medical marijuana users can customize their medicine, while recreational users can better control what kind of high they experience. This is possible by vaping/smoking strains with certain THC-to-CBD ratios, as well as taking THC or CBD oils for more precise dosing.

Determining what ratio works best is tricky, as each person’s brain reacts differently to the chemicals in cannabis. In addition to this, minor cannabinoids and terpenes within individual marijuana strains may also affect the way they work.

Generally, a 1:1 CBD-to-THC ratio will dull out the intoxicating psychoactive effects of THC. Increase it to a 2:1 CBD-to-THC ratio and the euphoric effects of THC are cancelled out entirely. Figuring out the correct ratio for a specific condition or individual typically takes trial and error to fine-tune the dosage and ingestion method to discover what works best.

THC and CBD: Knowledge is Power

With all of the theories, studies, and anecdotes, one thing is clear: marijuana isn’t one-size-fits-all for recreational or medical users. From getting the ideal high to treating a specific medical condition, it’s not enough to ingest any old strain. When it comes to CBD vs THC, percentages and ratios matter. By understanding the difference between CBD and THC, people raise the likelihood of receiving better relief from their medical symptoms or having a more positive experience with marijuana overall.

Dorothy Harris - CNBS Author: Dorothy Harris
Dorothy is far from being a pot-head. Actually, when we first met she wasn’t very familiar with cannabis - but with her excellent research skills and drive for knowledge, it didn’t take her long to master the field. Dorothy comes from a scientific background and is in charge of researching and writing our advanced scientific and medical topics, as their correctness is not something we are willing to compromise on. Dorothy specializes in top notch research, making sure no stone is left unturned.
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