For those who count themselves among the cannabis culture, many understand THC, trichomes, and even cannabinoids like CBD. But what about terpenes? Or is that terpenoids? What are these sibling resins within the cannabis flower and what function do they play?
Terpenes, which are aromatic compounds, are hydrocarbons that are produced by a wide range of plants, not just cannabis. Terpenoids are simply terpenes that have been chemically altered. They are most noted for producing the pungent smell that characterizes marijuana, both when it is growing and after it has been harvested.
More Than Smell
Terpenes and terpenoids, however, play a larger role than the mere production of odor. Like amino acids, they are powerful building blocks within the plant’s physiology that aid in the production of vitamins, hormones, pigments, resins, and — yes, that most cherished part of the herb — cannabinoids. Cannabis plants release more terpenes when temperatures are higher.
Cannabis plants can produce more than 200 terpenes. Like cannabinoids, terpenes are produced in the trichomes and constitute roughly 10 to 20 percent of the total resin in the trichome. It is estimated that 10 to 30 percent of smoke resin produced by marijuana comes from terpenes and terpenoids.
Terpenes also play a therapeutic role in medicinal applications of cannabis. They bind to both neurological and cannabinoid receptors in the body and brain and sometimes regulate the permeability of cell membranes. This allows terpenes to do things like control the amount of THC that a cell in the body can ingest. Thus, a strain with the right mix of cannabinoids and terpenes could result in a finely tuned medicine for a particular disease or ailment.
The most common terpene in cannabis is myrcene, which is also found in high amounts in mangos, hops, and lemon grass. It delivers a variety of therapeutic benefits, including antimicrobial, antiseptic, antioxidant, and anti-carcinogen. Myrcene also helps more THC to reach brain cells. As the most common terpene in marijuana, most cannabis users will be very familiar with its smell: Earthy, green vegetable-like, and sometimes carrying hints of citrus or fruit.
In fact, this is the source of the rumor that one can eat mangos, which contain large amounts of myrcene, before smoking marijuana to amplify the effect of the THC. Because the cannabinoid THC itself has no smell, drug dogs can’t detect it. Thus, they must be taught to go after a terpene instead. Most are trained to seek out the smelly caryophyllene oxide terpene.
Terpenes also play a protective role in the cannabis plant, helping it fight off bacteria, fungus, and insects. For gardeners, terpenes are both good and bad: While they protect the plant from fungus and infestation, they also notify human visitors or neighbors—including law enforcement—that cannabis plants are in flower and there’s about to be a harvest.
The next time you detect an especially aromatic variety of cannabis, don’t think THC or CBD, but instead remember the humble terpene. Without these amazing and therapeutic chemicals, countless strains of cannabis, like all varieties of Skunk and Cheese, would have no name.
This post was originally published on April 25, 2015, it was updated on October 5, 2017.