Terpenes in cannabis - what are they and how do they work?
Cannabis contains more than 150 types of terpenes. Although most terpenes are present in only trace amounts, the most important ones combine to create the characteristic aroma profile of each cannabis variety. For example, the combination of terpenes in the Sour Diesel variety determines the character of its diesel smell, while in Cherry Pie it evokes the pleasant aroma of sweet and sour cherry pie fresh out of the oven. As well as providing cannabis with a unique combination of aromas, terpenes have other functions in the plant and can induce a range of therapeutic effects in cannabis consumers, as well as influencing mood. Terpenes are naturally occurring compounds found in the trichomes of female cannabis plants. Trichomes are sticky, translucent glands that cover the surface of the flowers (stamens) and, to a much lesser extent, the leaves and stems. Crucially, trichomes contain resinous glands that produce terpenes.
Terpenes play an essential role in the growth and survival of the cannabis plant. As well as producing the characteristic aroma, these organic compounds contribute to the colour and pigmentation of the leaves and buds and to the taste of the cannabis plant. In short, terpenes help make the plant more attractive to some creatures while deterring others that may harm it. Some terpenes, such as geraniol, repel insects or herbivores that might try to nibble on cannabis. Other terpenes, such as terpinolene and linalool, attract insects and other small creatures that may help spread the pollen. These aromatic compounds support the plant's immune system by relaying information about the surrounding environment, protecting the plant from stressors and pathogens and helping to trigger its immune responses.
A number of variables can affect the amount of terpenes produced by a cannabis plant. Factors such as whether the plant is grown outdoors or indoors, exposure to light or heat, certain growing media, nutrient levels and harvest time all affect terpene levels. Many terpenes are classified as volatile compounds, which means they are easily lost during standard cannabis extraction processes. However, growing awareness of the therapeutic value of terpenes is leading to more sensitive extraction methods, such as the production of so-called living resin. Live resin is made from freshly frozen cannabis plants and very low temperatures are maintained throughout the extraction process to protect the terpenes and other volatile compounds in the plant. This results in a more fragrant and flavorfully complex cannabis experience.
Awareness of the aromatic properties of terpenes is not new. People have long used the scents associated with terpenes to produce essential oils for practices such as aromatherapy. For example, anyone who has dabbed lavender oil containing linalool behind their ears knows that it can potentially help you relax. Similarly, the terpenes in some varieties of cannabis can enhance its effects. However, terpenes seem to do more than bring a sense of well-being and stress relief. Terpenes are also considered a new field in cannabis medicine. Until recently, attention has focused almost exclusively on the medicinal properties of cannabinoids such as THC and CBD, but as our knowledge of terpenes improves, it is becoming clear that these aromatic compounds have health benefits too. Not surprisingly, some of the effects of terpenes on humans resemble their function in the plants themselves. For example, they help fight unwanted microbes and pathogens.
Therapeutic effects of terpenes
Preclinical animal studies and in vitro studies in test tubes have identified a number of therapeutic effects of terpenes. However, it should be noted that research on terpenes is in its infancy and has not yet been carried out on humans. Further research is needed to increase our knowledge of these compounds.
Antivirals
Researchers are still searching for new antiviral compounds. Many terpenes, including alpha- and beta-pinene, caryophyllene, camphor, and carvone, could show potent abilities to help kill viruses.
Effects against cancer
The increasing incidence of many forms of cancer has led to a diligent search for compounds to help suppress it. Certain terpenes, including those found in cannabis, may have anticancer effects, specifically helping to suppress the activity or growth of cancer cells. For example, limonene, along with other terpenes such as pinene, camphor, terpinene and beta-myrcene, may be particularly important anti-cancer and anti-tumour agents. One potential unique advantage of using terpenes is that they are unlikely to affect healthy cells and cause side effects, which is important for cancer treatment.
Antidepressants
Plant extracts containing terpenes are used in the production of a quarter of antidepressants. Among the many plant extracts used in antidepressants, linalool and beta-pinene are common.
Antimicrobial
A large number of terpenes can exhibit antimicrobial activity, or the ability to stop harmful microorganisms. Terpenes that may assist in killing or stopping the progression of microorganisms include alpha-bisabolol, geraniol, menthol, eucalyptol and terpinolene.
Pain relief
Scientists have found that some cannabis terpenes can mimic cannabinoids by producing a pain-relieving effect. In a 2021 study that combined terpenes with cannabinoids, researchers revealed that this combination amplified the pain-relieving effects without increasing the negative side effects. This interaction could suggest a so-called "entourage effect" (more on this below). Terpenes that may promote pain relief include humulene, geraniol, linalool, and β-pinene (beta-pinene). Fascinatingly, the above study also found that these terpenes activate the body's CB1 receptors, which are part of the endocannabinoid system and affect pain perception.
How can terpenes affect the effects of cannabis?
New evidence suggests that all the plant compounds in cannabis act synergistically. This phenomenon is known as the entourage effect and can be thought of as working as follows: the sum of all the compounds present in cannabis is greater than the sum of its parts. In other words, a special synergy of the whole plant occurs when cannabinoids and terpenes are consumed together, as opposed to when they are consumed separately. For example, terpenes appear to play a role in influencing the effects of THC and CBD in the body. In a 2018 review study of people with epilepsy, those who took a full-spectrum CBD extract (containing all cannabinoids and terpenes) experienced a reduction in symptoms and fewer side effects than those who took a CBD isolate (containing only cannabinoids, or more specifically, only CBD). Full-spectrum hemp extract is a whole-plant medicine that contains all the cannabinoids, terpenes and other compounds present in the plant.
The researchers also found that full-spectrum CBD extract was four times more potent than CBD isolate, meaning patients could take significantly lower doses. They attribute this effect to the therapeutic synergy of cannabinoids and other compounds such as terpenes. More recent research has found that terpenes increase the activity of cannabinoids, but high concentrations of terpenes were needed for this increase to take effect. It is essential to note that much is still unknown about terpenes and their interactions with other terpenes, cannabinoids and flavonoids present in cannabis. Moreover, most of the available research is based on animal or test-tube testing. However, the growing clinical interest in these aromatic compounds is yielding some fascinating findings. It is likely that in the coming years there will be a more sophisticated understanding of terpenes and their individual and synergistic actions.
The three main terpenes in cannabis
As we have already mentioned, there is a staggering amount of terpenes in cannabis - more than 150 different types to be precise. While many of these are found in very low concentrations, some have a stronger presence. Here's an overview of the three terpenes that predominate in cannabis
Myrcene
Most cannabis cultivars are dominated by either myrcene or caryophyllene. Myrcene, a terpene also prevalent in hops and lemongrass, is described as imparting an aroma with herbal, spicy, earthy and musky notes. Myrcene imparts a slightly sweet flavour profile to cannabis. It is also found in mangoes. In addition to contributing to the characteristic aroma of cannabis, myrcene may also have anti-inflammatory properties. A 2015 study on cultured cells suggested that myrcene may effectively reduce inflammation associated with osteoarthritis. This terpene also appears to help prevent the breakdown of cartilage cells, slowing the progression of osteoarthritis and reducing the production of some inflammatory cells produced by the body. Myrcen Could be used in the future to alleviate inflammatory diseases and their symptoms.
Caryophyllene
Caryophyllene, also known as beta-caryophyllene or β-caryophyllene, gives some cannabis varieties a spicy flavour. Caryophyllene is also found in other plants such as cloves, rosemary, oregano and black pepper. If you smell a particular cannabis strain and detect any of these smells, it is probably because caryophyllene is present. Caryophyllene is the only known terpene in cannabis that can bind to the CB2 receptor in the body's immune system. Because of this unique action, caryophyllene is sometimes also referred to as an atypical cannabinoid. Research into the therapeutic effects of caryophyllene shows that it has the potential to alleviate symptoms in a variety of conditions such as colitis, diabetes, cerebral ischemia, anxiety and depression, liver fibrosis and Alzheimer's-like diseases. Caryophyllene activity at the CB2 receptor could be used to treat conditions that are accompanied by inflammatory symptoms
Limonen
Clean, fresh, uplifting citrus scents - the name limonene reveals the aromas associated with this terpene. Limonene is found in the peels of citrus fruits and ginger. This terpene is also prevalent in many varieties of cannabis, which have a fruity, fresh scent. Limonene appears to alter the way some immune cells in the body behave, which may protect the body from a number of disorders. In one In one study, limonene helped increase the production of antibody-producing cells in the spleen and bone marrow, which the immune system uses to identify and neutralize pathogenic bacteria and viruses. Scientists have also recently suggested that limonene's unique therapeutic profile could also be useful in the treatment of Covid-19.
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