In popular coverage of cannabis, cannabidiol (CBD), the primary non-intoxicating cannabinoid, is often characterized as functioning in opposition to tetrahydrocannabinol (THC), which generates the intoxicating effects commonly understood as the cannabis “high.”
There is some truth to the characterization. A 2020 literature review reports that “the modulatory ability of CBD on THC effects has been described since the early 1970s with contradictory results,” adding that “the relationship of the two major cannabinoids is far from being simple or clear.”
Another literature review, published in 2021, highlights the contrasting effects of each cannabinoid specifically on blood flow. Apparently, “THC seems to increase brain activation and blood flow, whereas CBD seems to decrease brain activation and blood flow.”
The main takeaway? Combining CBD with THC won’t necessarily cancel the side effects of THC.
In this post, we’ll dive into the most current literature exploring the impact of CBD on the negative side effects of THC. We’ll also briefly explain how you can explore varying ratios of CBD to THC on your own.
While the studies examining the effects of CBD consumption on the effects of THC are mixed, the current public understanding of CBD’s effects on THC generally assumes that CBD will counteract any negative effects of THC, such as red eyes, paranoia, or greening out.
Evidence suggests that the way CBD affects your THC experience is determined by a variety of factors such as the ingestion method, the dose of THC, the dose of CBD, and more.
For example, a recent study published in 2023 in the American Medical Association’s JAMA Network Open journal found that CBD may actually increase the intensity of THC’s effects. While this finding may surprise you, it makes sense based on the parameters of the study.
A typical cannabis consumer will usually consume between 5mg of CBD up to 50mg of CBD. This study had three groups: no cannabis extract, 20mg of THC with no CBD, or 20mg of THC with 640mg of CBD. 640mg of CBD is a very high dose, rarely consumed outside of a lab setting. A dose that high is likely to produce mild sedating side effects in most people.
Additionally, the researchers had the subjects orally ingest the compounds, which means that ingested cannabinoids are subject to first pass metabolism in the liver. Generally, experiments assessing how CBD affects THC have had subjects inhale the cannabinoids, so they are ingested through the lungs directly into the bloodstream and are not subject to first pass metabolism.
This point is relevant because “evidence from the few published clinical studies suggests that Δ9-THC and CBD interact with pharmaceutical drugs, as well as with each other, via inhibition of cytochrome P450 (CYP) enzymes.” Essentially, Δ9-THC and CBD can interfere with specific enzymes called cytochrome P450 (CYP) enzymes. When these enzymes are inhibited, it can lead to an increase in the amount of medication in our bloodstream, and it might take longer for the medication to be removed from our system.
That’s why this study focuses explicitly on cannabis products intended for oral consumption. When you eat or drink cannabis rather than inhale it, the Δ9-THC in your cannabis product is metabolized as 11-OH-Δ9-THC, which can result in a subjective cannabis experience that is longer and more intense than inhaled THC. (Is 11-OH-Δ9-THC 10 Times Stronger Than THC?)
“Prior controlled Δ9-THC and CBD studies have predominantly used inhaled routes of administration, meaning much of the extant data regarding acute interactions between Δ9-THC and CBD may not translate to oral cannabis products (ie, edibles), which undergo first-pass metabolism in the intestine and liver before reaching the systemic circulation,” the study’s authors write.
The study compared the experiences and intoxication levels of a group of participants who each consumed an edible containing 20 mg of THC on its own against those of another group who each consumed an edible containing 20 mg of THC and rather high doses of 640 mg of CBD.
In observing the two groups, the authors found that the edible containing both cannabinoids “produced more pronounced effects, greater impairment of cognitive and psychomotor function, and increases in HR relative to both Δ9-THC and placebo.”
Another study, published a year prior and exploring inhaled cannabis doses of 10mg THC and 10 mg, 20 mg, or 30 mg of CBD, found a slightly different result, stating that “the co-administration of CBD with THC had no effect on the induction of either cognitive impairments or psychotic symptoms following cannabis use.”
A 2020 literature review, referenced above, further complicates any specific characterization of the interaction between CBD and THC by describing a history of contradicting studies. This review also offers several explanations regarding why the current understanding of the relationship between CBD and THC remains so unclear.
“Based on the studies discussed, and a thorough literature review of relevant papers, it is likely CBD modulates THC and its effects in variable capacities, and therapeutic potential depends highly upon several factors: dosage concentration, route of administration, ratio of cannabinoids, time of cannabinoid administration (concomitant or separated in time), and patient history and extent of cannabis use,” the authors state.
The authors also point out an issue Jointly has covered before: the lack of regulation governing the quality and label accuracy of CBD products available to consumers.
Why does this lack of clarity matter? As the 2020 review authors put it: “[There is] a strong likelihood that patients or recreational users may misinterpret the varying degrees of CBD efficacy. From a clinical standpoint, in an attempt to counteract some level of adverse THC effect, patients may inadvertently increase its effect if they are not careful to select an appropriate dosage and ratio of THC:CBD.”
Despite what the academic literature says, Jointly users have actually indicated that consuming CBD and THC has had a positive impact on the negative side effects they encountered due to THC consumption during their own incorporation of cannabis into their respective wellness routines.
While we don’t have enough data to fully explore the mechanism behind why Jointly users’ experiences contradict what is reported in the studies covered above, this contradiction does indicate that it could be worthwhile to experiment with different CBD:THC ratios on your own with the help of the Jointly App to not only track your unique individual response to different cannabinoid ratios and products, but also to find trustworthy cannabis products from vetted sellers.
One brief article, published in the “Hot Topics” section of the journal Neuropsychopharmacology in 2018, reports that retail cannabis products in legal states offer a huge range of CBD to THC ratios, starting at a 1:1 ratio and going up as high as 80 parts CBD to 1 part THC. This doesn’t quite reach the full range of the 2023 study covered above, which used a CBD to THC ratio of 320:1.
To maximize how well you’re able to modulate your own CBD to THC ratios for your own experimentation, we recommend mixing THC-rich cannabis flower with CBD-rich cannabis flower. Be sure to acquire both products from a reputable vendor and read the certificate of analysis (COA) for each product. This will allow you to have an approximate measure of how much CBD and THC is in each joint you smoke, for example, and you can then modify those measurements to better suit your needs.
It's also important to consider the role that terpenes play in the subjective experiences of cannabis users. Myrcene, linalool, and beta-caryophyllene, for example, tend to have sedative or calming effects, while limonene, terpinolene, and humulene tend to be associated with more energetic or euphoric experiences. A wide range of other factors, such as whether you’ve slept enough or eaten well, can also have an impact on individual cannabis experiences, including those experiences which include negative side effects.
Jointly is the cannabis discovery app that makes it easy to find and shop the best cannabis and CBD products for your goals. Your matches are calculated from the real product ratings and experiences from hundreds of thousands of people using the Jointly app.
With Jointly, you can shop your top-rated products, and save lists of your favorites to share and bring to your local dispensary to help guide your shopping experience.
The Jointly app also helps you improve your cannabis experiences by uncovering what’s working and what’s not with reflections and personalized insights. In fact, the quality of your diet, how much you slept, who you’re with, and the time of day are just some of the factors that can impact your cannabis experience.
So if you're ready to find your best products and enjoy your perfect cannabis experience, download the Jointly app today on the App Store or Google Play, or shop your matches on the Jointly website. Discovery awaits.