Terpenes are responsible for more than just cannabis’ distinctive scent.
Terpenes are biologically active molecules that have a chemical structure that gives them aroma, often quite intense. They are in many everyday items such as foods and air fresheners, and they are present in cannabis, among other things. These compounds are the reason for the aroma and taste of cannabis. Cannabinoids such as CBD or THC do not have a strong taste or smell.
The medical cannabis user could say, “Interesting trivia, but is it otherwise important that I know about terpenes?” My answer is yes, and in the future, I believe it will be a resounding “Yes!” Unfortunately, the science of exactly how important terpenes are to the medical effects of cannabis is still in progress.
Like many things in science and medicine, the more we learn, the more we discover how much more there is to learn, but as this work continues, the future could result in patients being able to precisely tailor their therapy. Imagine a time when you are not simply using an indica or sativa but are instead homing in on specific cannabis profiles that cover all your individual needs.
We are not at that point yet, but in some ways, we are getting close. The primary active molecules in cannabis are the cannabinoids CBD and THC, and the amount of CBD and THC affects the therapy. There are other cannabinoids with additional effects, and then there are terpenes. These terpenes can have their own effect and can also enhance the effects of THC, CBD or other cannabinoids. The analysis of exactly what active molecules are present in a type of cannabis is called a chemovar.
Many have seen terpene charts or lists that show their effects, but where does this information come from? At this point, most of those listed effects are extrapolations of animal data or they are probable effects based on likely physiological mechanisms. There have been few clinical studies in humans that show exactly how effective terpenes are. There are many difficulties with extrapolations such as this. What occurs in lab animals does not always work in the somewhat different physiology of the human body. The dosing given in the lab can be drastically different from what is available in natural cannabis. Also, there are huge variations in terpenes available between strains. Finally, there is even significant variation in terpenes available in different samples of the same strain.
At this point, you are probably thinking, “Doc, you have done a great job showing that this is not well understood and is complicated. You have done a very poor job of showing why it is important that I care.” For one, while there is limited evidence, that does not mean no evidence. A clue from the world of prescription pharmacy that terpenes do play a role for humans is the lack of popularity of Marinol, a pharmaceutical that is pure THC. On the other hand, Sativex, now marketed as a 1:1 THC:CBD nasal spray, also has 6 to 7 percent terpenes. Sativex has become a much more accepted therapy in the nations where it is prescribed. There are companies such as Ebbu that are working to create specific terpene profiles. They are testing them in controlled, double-blinded studies. They are studying the exact concentrations to give specific effects. Looking less far in the future, a reason you should care is that with the recent passage of the “unity bill,” soon you will have the cannabinoid and terpene profile of each product sold readily available to you in Oklahoma dispensaries. You will be able to choose products not just based on a clever strain name and suggestions from friends or the internet. You will be able to pick and choose targeted relief. Instead of asking for an indica or sativa and wondering why sometimes they are more helpful than others, you will be able to look at the specific profile and pick products that have the therapeutic molecules in the concentrations that you find most effective.
Let’s look at some examples for you. There are terpenes known to have memory enhancing effects. For example, alpha-pinene is a terpene often present in strains such as Blue Dream or Jack Herer. This terpene is the most prominent of several that have been found to inhibit the acetylcholinesterase enzyme. This can boost acetylcholine levels in the brain that can aid in memory and recall. Also, alpha-pinene can help prevent the memory impairment that can occur with THC. Depending on the needs of the cannabis user, this could be helpful or maybe it might need to be avoided. For example, let’s say you were dealing with anxiety while writing a manuscript. Pinene might help keep your memories sharp while obtaining anxiety relief from cannabis. But if you have PTSD, memory enhancement might be a component of therapy that you want to avoid.
A second example would be those cannabis users who are particularly sensitive to THC. Some can have psychotomimetic (psychosis-like) effects from even low to normal doses of cannabis. It is known that CBD helps to counter these effects along with the more common anxiety and paranoia that THC can cause. Yet several terpenes such as myracene, limonene, and alpha-phytol can act at the GABAA receptor. This is another mechanism to calm this effect. This could be particularly beneficial to patients weaning off benzodiazepines such as Xanax or those trying to use less alcohol.
There are many other ways that terpenes might assist the medical cannabis user. As with all medications, there are differences in the effects that each individual feels. So it is a great idea to keep track of what chemovars you find beneficial. You can then look for similar terpenes and cannabinoids in other products.
Dr. Steven Ross, MD
Dr. Steven Ross is a physician who has practiced and taught medicine in several countries worldwide and is now a practicing cannabis clinician and founder of MMDOKC in Oklahoma City. He has a passion for assisting patients with cannabis recommendations and guidance for medical use.