You’re probably familiar with the big two cannabinoids, tetrahydrocannabinol (THC) and cannabidiol (CBD), but there are many other compounds that contribute to the overall experience and benefits of medical cannabis.
Among these lesser-known but important compounds are terpenes. Researchers are studying terpenes for their potential health benefits as well as for how they may interact with CBD, THC and other cannabinoids to produce a greater overall therapeutic effect.
Cannabis plants contain over 150 types of terpenes, with each cannabis strain containing a different terpene profile. There’s a lot to uncover about terpenes, such as the health benefits they may have, their role in the entourage effect and which terpenes are responsible for certain effects.
What Are Terpenes?
Terpenes are aromatic compounds that contribute to a plant's unique smell and taste. Terpenes aren’t only found in cannabis – they exist in many plant species, and are responsible for the citrusy scent of lemons (limonene) and the calming floral aroma of lavender (linalool). Thousands more exist in nature and they are a common ingredient in essential oils, cosmetics, cleaning products, medications and perfumes.
In the cannabis plant, the majority of terpenes are found in the flowers or buds. If you examine a cannabis flower, you’ll notice millions of tiny crystals that form a sugary coating. These are called trichomes. Trichomes contain a high concentration of terpenes and provide protection from invasive insects and other environmental stresses.
Cannabis growers target the development of terpenes through several methods. Factors that can influence the terpene content of a cannabis strain include light exposure, indoor or outdoor growing, temperature, nutrient levels and harvest practices. Many terpenes are volatile compounds (meaning they easily evaporate at room temperature) and can be lost during some cannabis extraction methods.
Until recently, the varying cannabinoid content was thought to be the main differentiator between cannabis strains. But it’s now thought that the terpene content may also play a role in the effects of a particular cannabis strain.
Which Terpenes Are Found In Cannabis?
Cannabis contains over 100 different terpenes, but researchers tend to focus on a select few that may have medicinal properties. These terpenes are often defining features of a particular cannabis strain:
Common household spices including pepper, cinnamon, cloves and oregano contain caryophyllene. It has a peppery, spicy scent and recent research suggests it may have anti-inflammatory properties. Caryophyllene is commonly found in more ‘uplifting’ cannabis strains.
Myrcene has an earthy, herbal aroma and is found in mango, hops and lemongrass. Myrcene may have some anti-anxiety properties, but most studies on this have been on animals or in vitro (not in a live test subject). Myrcene is often found in cannabis strains designed to help with sleep.
As you might have guessed, pinene is responsible for the distinct scent of pine trees. It’s also found in cinnamon, tea tree oil, basil, rosemary and dill. Researchers are studying pinene for its potential anticonvulsant and neuroprotective properties. Pinene may also act as a mild bronchodilator, meaning it may widen the airways and ease breathing in people with conditions such as asthma.
This terpene is found in lavender, citrus plants and roses, and has a sweet, floral scent. It may have some anti-anxiety properties, but this has only been shown in animal studies. It’s also popular in nighttime cannabis strains for its potential sedative effect.
Limonene smells of citrus and is found in lemons, fruit rinds, rosemary, juniper and peppermint. Studies have found that limonene may also have neuroprotective properties, meaning it may help prevent the development of conditions such as multiple sclerosis, epilepsy and Alzheimer’s disease.
Are Terpenes Psychoactive?
On their own, terpenes aren’t considered psychoactive. Although they may have some mild sedative effects, they don’t lead to intoxication or alter the brain in any way significant enough to be called psychoactive, unlike THC.
The scent and flavour of terpenes may influence your mood, however. Many people use the scent of lavender as a sleep aid, for instance. Terpenes can alter the scent and experience of consuming medical cannabis in similar ways, with certain aromas causing subtle changes in your mood.
Beyond just influencing the flavour and smell of cannabis, terpenes may also interact with THC and other cannabinoids and influence the psychoactive effects of cannabis. This is what’s known as the entourage effect.
How Do Terpenes Interact With Cannabinoids To Create The Entourage Effect?
The entourage effect is the theory that terpenes work together with cannabinoids in cannabis to create a greater therapeutic effect. The term was coined in an influential 1998 paper, where researchers proposed that cannabis products may be more medically beneficial when the plant’s entire spectrum is utilised, compared to extracts that only contain specific compounds.
Terpenes may play an important role in the entourage effect, but researchers aren’t sure exactly how they interact with cannabinoids and other cannabis compounds. A recent review of the available research suggested that terpenes may enhance the effects of THC and/or CBD, but that we need more high quality research to confirm this.
Another review suggests that terpenes may contribute to an entourage effect by affecting how psychoactive active compounds such as THC bind to cannabinoid receptors, or by slowing the rate at which THC degrades in the body.
Some anecdotal reports also support the idea that terpenes may play a significant role in the effects of different cannabis strains. But there is some research that questions this, such as one study that found terpenes may not directly affect cannabinoid receptors. This may mean that if terpenes do influence the experience of cannabis, it’s likely through a mechanism other than directly affecting the cannabinoid receptors.
Another recent study also suggests that terpenes aren’t active at cannabinoid receptors. Neither of these studies dismiss the idea of terpenes influencing the entourage effect, but they do emphasise that it needs more clarification and research.
The Rising Popularity Of Terpenes
Terpenes enrich our world with thousands of varied smells and tastes. They are of great interest to cannabis experts, but those new to medical cannabis might also benefit from learning about their effects and potential benefits. It can be a daunting subject, as there are many different terpenes that may hold different therapeutic benefits or alter the experience of cannabis in varying ways.
Future research will hopefully further clarify the role of terpenes in a possible entourage effect, where terpenes and cannabinoids may work together to deliver a greater therapeutic benefit. For now, we can appreciate terpenes for adding flavour and smells to different medical cannabis strains, foods and plants.