According to a new study only the terpenes Limonene, Ocimene, Terpinol and Borneol enhance the effect of THC
A new Israeli study challenges the assumption that certain cannabis terpenes enhance the effect of THC. Yet according to this research, some terpenes like eucalyptol (Eucalyptol), myrcene (Myrcene), caryophyllene (Caryophyllene), bisabolol (Bisabolol) terpenes, all were found not to enhance the effect of THC.
The new study was conducted by Bazelet Pharma, in collaboration with the Hebrew University of Jerusalem and the Open University, and was published in the scientific journal Journal of Biochemical Pharmacology.
For the purposes of the experiment, the researchers examined the effect of THC alone, compared to a combination of THC with different terpenes, on isolated cells of the human body's cannabinoid receptor called CB1, and measured the intensity with which each of the two combinations activates this receptor.
The results of the study clearly showed that the combination of THC with certain terpenes present in cannabis, causes THC to activate the cannabinoid receptor CB1 with a higher intensity than THC alone, thus enhancing the effect
In the first condition of the experiment, the researchers tested a combination between THC and different terpenes where the dose of terpenes remained constant at 10μm (micron/micrometer) and the dose of THC gradually increased.
In the graphs below, taken from the study, you can see, for each of the terpenes tested, the intensity with which different doses of THC without the terpene activated the receptor (the black curves), compared to the intensity with which the combination of THC with 10μm of the terpene activates the receptor (the red curves)
As you can see, the discrepancy between the red and black curves is clear in nal terpenes and particularly significant in some terpenes, showing that they greatly enhance the effect of THC.
Another interesting thing to notice in the graphs is that the gap between the red and black bars often narrows as the dose of THC increases.
For example, in the graph of the terpene Sabinene (Sabinene) in the lower left corner marked with the letter J, you can see that the gap between the black curve of THC alone and the red curve of a combination of THC and Sabinene is very important at low doses of THC, but decreases as the dose increases, and at the highest dose measured, the difference is already relatively small. It can be concluded that the reinforcement that terpenes give to the effect of THC is greater at low doses of THC, although for some of the terpenes there is still a significant gap in the strength of the effect even at high doses. . .
In the second condition of the experiment, to produce blends that would be more similar to the naturally occurring state in the real cannabis plant in terms of the ratio of THC to terpenes, the researchers changed the amount of terpenes and their to THC so that they are similar to average amounts of cannabis.
As we know, the average concentration of terpenes in cannabis flowers is currently around 1,5%, and the average concentration of THC is around 15%, so the typical ratio between terpenes and THC in the cannabis is a 1:10 ratio, and so that's the ratio the researchers used in the blends they tested in the second condition of the experiment.
The second condition of the experiment is particularly important, because this is the big difference between the current study and previous studies that came to the opposite conclusion.
The researchers note 3 previous studies carried out on the subject, which concluded that terpenes do not improve the effect of THC, and they claim that the reason for reaching this conclusion in the past is due to the use of mixtures of THC with terpenes in a 1:1 ratio or with more terpenes than THC, which which is not similar A rule for the natural relationship between them in the cannabis plant.
Additionally, the researchers claim that using too high a concentration of terpenes in these earlier studies prevented them from dissolving evenly in the mix with the THC – another issue that may have affected the results.
As a counterexample, researchers cite another study in 2020, which showed that when the ratio between terpenes and THC is similar to the actual ratio that exists in the cannabis plant, the terpenes actually enhance the effect of THC, as was also observed in the present study .
In the new study, in most of the terpenes tested, the advantage of the mixture of THC in combination with a terpene compared to THC alone, was also preserved in the second condition of the experiment, where the ratio between terpenes and the THC was 1:10.
The results of this condition of the experiment, shown in the graphs below, show that the enhancing effect of adding terpenes to THC exists even when the ratio of terpenes to THC is similar to its natural ratio. in the cannabis plant, when the terpenes that enhanced the effect of THC the most were Limonene, Ocimene, Terpinol and Borneol.
On the other hand, concerning the terpenes eucalyptol, myrcene, caryophyllene, bisabolol, and more, it was not found in this condition of the study, which compared the ratio with that of natural cannabis, because they boost THC.
“The addition of certain terpenes may allow a reduction in THC dose for some patients, thereby reducing the side effects associated with THC, which will help tailor treatment to more sensitive populations such as children and the elderly,” write the researchers
In other words, since the results of the study showed that the most significant boost in the addition of terpenes was obtained for low doses of THC, one of the conclusions of the study is that a low dose of THC with the addition of terpenes can be just as effective as a higher dose of THC alone, but with fewer side effects associated with THC.
This conclusion is highly relevant to the company Basalt Pharma behind the research, which filed a patent in 2017 on the very concept of cannabis oil enriched with terpenes in order to reinforce its effect. This patent application is still pending approval to date, and this new study could provide scientific support that could help the patent application to be granted.
The results of the new study are certainly interesting, and although they are not unequivocal proof of the theory that terpenes also play a role in entourage effect (meaning a synergy between cannabinoids and other components of cannabis that has a different effect compared to each cannabinoid individually), they reinforce it.
The researchers' criticism of the shortcomings they claimed to have in previous studies on the subject, may explain why those studies came to the opposite conclusion. Bottom line – it remains to be seen whether future studies will provide further support for these findings.