THC vs CBD: What You Need to Know

THC and CBD are the two most prominent compounds in cannabis, and therefore have a large impact on the effects of this ancient plant. But are THC and CBD really so different? Below, we take an in-depth look at these two compounds, their differences and similarities, and the ways in which they may interact in the body and thereby alter our physiological experience on cannabis.

Getting to know the major cannabinoids

Cannabis is a complex plant that contains over 400 potentially active compounds. Cannabinoids compose just one group of these compounds, with close to 100 individual cannabinoids isolated from the plant thus far. Of these, THC and CBD are by far the most abundant, and therefore garner most of the attention from cannabis researchers and companies. Nonetheless, there is still plenty we don't know about these chemicals, and scientific research continues to unveil the many intricacies of how they work, both in their host plant and in our bodies.

Despite their prevalence, THC and CBD are not the first cannabinoids produced by the cannabis plant. Indeed, this title belongs to cannabigerolic acid (CBGA), which is produced early on in the plant's growth phase and is often considered the "mother of all cannabinoids". Over time, special enzymes in cannabis synthesize CBGA into other cannabinoid acids, such as THCA, CBDA, and CBCA. These compounds eventually become THC, CBD, and CBC as cannabis plants are dried/cured, or immediately when cannabis is combusted, vaporized, or cooked.¹

What are the differences between THC and CBD?

While they share a similar biosynthetic pathway, THC and CBD are very different compounds. They are often sourced from distinct subtypes of cannabis, and have different chemical structures and mechanisms of action, meaning they act in different ways in the body and ultimately produce notably different effects.

Plant origins

The cannabis plant features numerous chemotypes, or chemical variants, that feature different concentrations of THC, CBD, and other compounds. Ever since researchers discovered THC as the chemical that "gets us high", most breeders have focused their efforts on creating marijuana varieties capable of producing increasingly high concentrations of the cannabinoid. With some of today’s cultivars containing up to 30% THC and beyond, this is in shocking comparison to the year 1990, when cannabis samples were found to contain less than 10% THC.²

However, as interest in medical cannabis has increased, seed banks and breeders have begun offering cannabis varieties rich in CBD and other, less-abundant cannabinoids.

Hemp vs marijuana

The host plants from which CBD and THC are derived tend to feature a very different chemical structure and legal classification.

Hemp is a term used to refer to cannabis varieties bred and grown for industrial purposes, such as to make food, skincare and health products, textiles, construction materials, and even fuel. Hemp varieties have specifically been bred to produce low levels of THC (usually 0.2–0.3% depending on the region) in order to abide by anti-drug laws across the world. Hemp flowers, while low in THC and therefore non-intoxicating, can, however, contain relatively high levels of CBD; as such, they are often used to make CBD products such as tinctures, concentrates, and more.

Marijuana, on the other hand, generally refers to the dried flower of THC-rich cannabis varieties. While technically from the same species as hemp, the plants used in marijuana production have a very different appearance and chemical makeup. Marijuana plants are typically small and stocky (ideal for discreet indoor cultivation) and produce large flowers with lots of trichomes (crystal-like glands that produce cannabinoids and other desired chemicals). Hemp plants, on the other hand, can grow well over 2 meters tall with a long, strong central stem (ideal for fiber production), lanky branches, and wispy, light flowers with far fewer trichomes.

Note: given the rising interest in CBD and other non-intoxicating cannabinoids, cannabis breeders and seed banks have started developing cannabis varieties that produce the same dense, resinous flowers as marijuana plants but with high levels of CBD and low levels of THC, effectively combining the best of both worlds.

Chemical structure and mechanism of action

THC and CBD both contain 21 carbon atoms, 30 hydrogen atoms, and 2 oxygen atoms. However, a very slight difference in how these atoms are organized (so slight that an untrained eye will struggle to notice it when looking at molecular drawings of the two chemicals) means that THC and CBD have very different mechanisms of action in the human body.

The endocannabinoid system (ECS)

Both THC and CBD act on the human endocannabinoid system—a complex regulatory system involved in mediating a wide variety of biological processes, and often touted as helping to maintain homeostasis (or equilibrium) in the body. However, given their different molecular structures, CBD and THC act on this system in different ways.

THC has a molecular structure that's very similar to that of anandamide, a fatty-acid neurotransmitter that our body produces naturally in very controlled amounts. Anandamide acts on CB1 and CB2 receptors; CB1 is one of the most abundant G protein-coupled receptors of the central nervous system and is found in extremely high concentrations in the neocortex, hippocampus, basal ganglia, cerebellum, and brainstem.³ CB2 receptors, on the other hand, are generally found in higher concentrations in peripheral organ tissue, immune cells, and some neurons.

The interaction between these receptors and anandamide is similar to that of a lock and key; anandamide is able to fit into these receptors and thereby trigger a variety of biological reactions. Given its structural similarity to anandamide, THC can also bind to CB1 receptors, though with even greater efficacy, which makes for much more potent and longer-lasting effects.⁴

CBD, on the other hand, is a CB1 and CB2 antagonist, meaning it doesn't bind with either receptor in a traditional way. Instead, its mechanisms of action include potentially working as a negative allosteric modulator of the CB1 receptor, which basically means it can prevent other cannabinoids from binding to CB1 (see more below). It has also been researched for its ability to potentially increase levels of anandamide in the brain through its inhibition on the FAAH enzyme, which breaks anandamide down. In addition, research suggests CBD may act on serotonin, vanilloid, and GABA receptors, among others—so its effects appear to be diverse and widespread.⁵,⁶

Effects

Perhaps the most notorious difference between CBD and THC is their effects. The immediate effects of THC are notable and include euphoria, heightened sensations, and an altered perception of time and one's surroundings. In some cases, THC can also produce negative effects such as anxiety, paranoia, and nausea. There is also compelling evidence to show that THC may have promising medicinal benefits.

Unlike THC, CBD doesn't produce euphoria or intoxicating effects. Instead, the effects of CBD are much more subtle, but may still impact a person's mood, stress levels, pain, and more.

Psychoactive vs medicinal

There is a strong tendency to confuse THC as the main component for "getting high" and CBD as the non-psychoactive, "medicinal" compound in cannabis. While it's true that THC is largely responsible for the "high" we experience from cannabis, studies suggest that it may also have therapeutic benefits.

It is also true that CBD doesn't produce the same intense feeling as THC, and that it may exhibit a wide variety of medicinal benefits. However, the statement that CBD is non-psychoactive isn't true. While it won't make you feel intoxicated like THC, CBD has complex effects on mood and brain function, and, along with all the other components found in cannabis, even contributes to the way we experience the effects of THC and cannabis in general.

Legality

Both THC and CBD vary in terms of legality. While many places in the world continue to treat the entire cannabis plant as a controlled substance, some are beginning to make legal distinctions between cannabis plants and products based on their chemical makeup. Certain countries, for example, have either decriminalized or legalized CBD products while restricting the use of THC (or prohibiting it completely), while others have completely legalized cannabis in all its forms and derivatives.

Note: the laws surrounding cannabis are changing constantly. Our readers are responsible for remaining up to date on and abiding by their local laws regarding cannabis.

Drug testing

Even in places where cannabis is legal, people are often subject to drug tests (especially in certain occupational settings). Most of these tests look for metabolites of THC, whereas CBD metabolites (or the metabolites of any other cannabinoid, for that matter) aren't typically tested for. Keep in mind, however, that full-spectrum CBD products may contain trace amounts of THC that, depending on how much CBD you take and how often, may trigger a positive result.

Are there any similarities between THC and CBD?

While the purpose of this article is to highlight the differences between THC and CBD, it's also important to note that these two compounds have many similarities. Remember that THC and CBD both come from the same plant species (Cannabis sativa) and the same precursor molecule (CBGA). They also contain exactly the same atoms, and both act on the same biological system (albeit in very different ways). One of their biggest similarities, however, is that CBD and THC contribute to the unique ways in which we experience cannabis through the "entourage effect".

The entourage effect

The entourage effect is a term coined by cannabis researchers that may help to explain the complex ways in which cannabis acts on the body. In a nutshell, the entourage effect posits that cannabis compounds can synergise, thereby producing more profound or distinct effects when taken together, compared to in isolation.

A clear example of the entourage effect in action can be seen when we compare the effects of herbal cannabis to those of synthetic THC isolates such as dronabinol, the only form of THC approved for medicinal use by the US FDA. Dronabinol is sold under numerous brand names (including Marinol, Syndros, and others) and is taken orally as a gel cap containing between 2.5–10mg of synthetic THC. And while structurally the same as the THC found in cannabis, patients often report that dronabinol is much stronger than herbal cannabis, yet less effective.⁷

The entourage effect may hold answers as to why that is; CBD, as mentioned, has been shown to work as a negative allosteric modulator of CB1 receptors, meaning it makes them less available to bind to compounds like THC. This is why dispensaries, integrative health clinicians, and many other sources often recommend using CBD to mitigate the intense high of THC, or choosing strains with more balanced THC:CBD ratios for a less intense experience.⁸

Remember that when we're talking about THC and CBD, we're really just talking about two of the 400+ biologically active compounds in cannabis. While studies into these compounds are ongoing, there's still a lot more to cannabis that we don't know. Just like CBD can affect the way we experience THC, the hundreds of other compounds found in the cannabis plant may act similarly through the entourage effect.

The importance of THC:CBD ratios

At NOIDS, we're big believers in balance. If you use or are planning to use cannabis, keep in mind that the concentrations of chemicals like THC and CBD in your herb will impact your experience. Experimenting with cannabis varieties featuring different ratios of THC and CBD is a great starting point to find a cultivar that produces the effects that are most beneficial to you.

Do you regularly cook with cannabis? Say goodbye to the days of accidentally burning your herb when decarbing or cooking, thanks to the POT Herb Cooker by NOIDS. Read more here.

References:

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2. Harring, R., & Friedman, L. Has marijuana actually got stronger since the 80s? Here's what the science says. Business Insider. Published August 27, 2016. Accessed October 21, 2022. https://www.businessinsider.com/is-weed-stronger-today-than-the-80s-2016-8

3. Kendall, D. & Yudowski, G. Cannabinoid Receptors in the Central Nervous System: Their Signaling and Roles in Disease. Front. Cell. Neurosci., 04 January 2017. DOI: https://doi.org/10.3389/fncel.2016.00294

4. Justinova, Z. et al. The Endogenous Cannabinoid Anandamide and Its Synthetic Analog R(+)-Methanandamide Are Intravenously Self-Administered by Squirrel Monkeys. J Neurosci. 2005 Jun 8; 25(23): 5645–5650. DOI: https://doi.org/10.1523/JNEUROSCI.0951-05.2005

5. Laprairie RB, Bagher AM, Kelly MEM, Denovan-Wright EM. Cannabidiol is a negative allosteric modulator of the cannabinoid CB1 receptor. British Journal of Pharmacology. 2015;172(20):4790-4805. doi:10.1111/bph.13250

6. Pertwee, R. The diverse CB1 and CB2 receptor pharmacology of three plant cannabinoids: Δ9-tetrahydrocannabinol, cannabidiol and Δ9-tetrahydrocannabivarin. Br J Pharmacol. 2008 Jan; 153(2): 199–215. DOI: https://doi.org/10.1038/sj.bjp.0707442

7. Armentano, P. Marinol vs. Natural Plant: PROS, CONS AND OPTIONS FOR PATIENTS. NORML. Published August 11, 2005. Accessed October 24, 2022. https://norml.org/marijuana/library/marinol-vs-natural-cannabis/

8. Sumpter, L. Does CBD Counteract THC's Psychoactive Effect? Royal Queen Seeds. Published April 22, 2022. Accessed October 24, 2022. https://www.royalqueenseeds.com/blog-how-cbd-counteracts-thc-n377