The unique musky, skunky, and pungent aroma of cannabis is unmistakable: Most people can smell it before they even see it. Terpenes, the aromatic compounds that determine the scent of many flowers and herbs, bestow cannabis with its distinctive odor and contribute to its flavor.
Cannabis contains more than 150 types of terpenes. Although most terpenes are present in only trace amounts, the more prominent ones team together to give diverse cannabis strains their signature scent profiles. The combination of terpenes in Sour Diesel tell you of its pungent, gassy character, while Cherry Pie evokes the pleasant scent of sweet and sour cherry pie fresh out of the oven.
Beyond providing cannabis with its unique bouquet of scents, terpenes also hold diverse functions in the plant and can produce a range of therapeutic and mood-altering effects in cannabis consumers.
Where do terpenes come from?
Terpenes are naturally-occurring compounds found in the trichomes of female cannabis plants. Trichomes are sticky, translucent glands that cover the surface of buds, and in much smaller amounts, on leaves and stems. Critically, trichomes contain resin glands that produce terpenes.
Terpenes play an integral role in a cannabis plant’s growth and survival. Besides producing distinctive aromas, these organic compounds also enrich color and pigmentation in leaves and buds, and contribute to the flavor of cannabis. In short, terpenes help to enhance the plant’s attractiveness to some creatures, while deterring others that can do harm.
Certain terpenes like geraniol, for example, repel insects or herbivores that might be tempted to snack on cannabis. Other terpenes, like terpinolene and linalool, attract insects and other small creatures that can help spread pollen. These aromatic compounds support the plant’s immune system by conveying information about the surrounding environment, protecting plants from stressors and pathogens and helping to trigger immune responses.
A sweep of variables can affect the amount of terpenes a cannabis plant produces. Factors such as whether the plant is grown outdoors or indoors, exposure to light, temperature, certain growing mediums, nutrient levels, and when harvesting is carried out can all influence terpene levels.
Many terpenes are volatile compounds, meaning 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 live resin.
Live resin is made from fresh frozen cannabis plants and maintains freezing temperatures throughout the extraction process to protect terpenes and other volatile compounds in the plant, leading to a more aromatically complex and flavorful cannabis experience.
How do terpenes affect the body?
Awareness of the aromatic properties of terpenes is not new. Humans have long harnessed the vibrant scents associated with terpenes to formulate essential oils for practices such as aromatherapy.
For example, anyone who’s dabbed lavender oil—which contains linalool—behind their ears knows that it can potentially help you relax you. Similarly, terpenes in certain cannabis strains can add to its effects.
However, the effects of terpenes appear to extend beyond feel-good benefits and stress relief. Terpenes have also been identified as a new frontier in cannabis medicine. Until recently, the spotlight has been focused almost exclusively on the therapeutic qualities of cannabinoids, such as THC and CBD, but as our understanding of terpenes grows more sophisticated, it’s becoming apparent that these aromatic compounds are medicinal powerhouses too.
All terpenes boast unique combinations of therapeutic properties. Unsurprisingly, some of the effects terpenes have on humans are evocative of their function in cannabis and other plants—like helping to fight off unwelcome microbes and pathogens.
Preclinical studies on animals and in vitro studies—in test tubes—have identified a range of therapeutic benefits associated with terpenes. It should be noted, however, that terpene research is in its infancy and has not been widely performed on humans. More research needs to be done to solidify our understanding of these compounds.
Researchers are always on the hunt for new antiviral compounds. Many terpenes could show strong abilities to help kill viruses, including alpha- and beta-pinene, caryophyllene, camphor, and carvone.
Rising rates of many forms of cancer are driving the quest to find compounds that can help suppress it. Some terpenes, including those found in cannabis, can exhibit anticancer activity, helping to inhibit the activity or growth of cancer cells.
Limonene could represent a particularly notable anticancer and antitumor agent, along with other terpenes such as pinene, camphor, terpinene, and beta-myrcene. One potential unique benefit of terpenes is that they may be unlikely to affect healthy cells or cause side effects—something important for cancer treatments.
Twenty-five percent of antidepressant drugs are formulated using herbal extracts that contain terpenes. Linalool and beta-pinene are common among many plant extracts used in antidepressant medication.
A vast array of terpenes may display antimicrobial activity, or the ability to halt a harmful microorganism in its tracks. Terpenes that may help in killing or stopping the progression of microorganisms include alpha-bisabolol, geraniol, menthol, eucalyptol, and terpinolene.
Researchers have found that some cannabis terpenes may mimic cannabinoids by creating a pain-relieving effect. In one 2021 study that combined terpenes with cannabinoids, pain-relieving effects were amplified without an increase in negative side effects. This interaction could indicate the entourage effect (more below).
Terpenes that may promote pain-relieving activity include humulene, geraniol, linalool, and β-pinene. Fascinatingly, the study above also found that these terpenes activate the body’s CB1 receptors, which form part of the endocannabinoid system and influence pain perception.