Of the many active ingredients in cannabis, cannabinoids — the miracle molecules that deliver most of the medical efficacy of marijuana — aren’t the whole picture. Some cannabis consumers may be aware of terpenes, the cannabinoid-like chemicals that give herb such a pungent smell. What most don’t know is that terpenes also deliver therapeutic relief, just like their cousins the cannabinoids.
Terpenes are produced in the trichomes of the plant, the nearly microscopic resinous stalks that cover the flowers and sometimes leaves. This is also where all cannabinoids, like THC and CBD, are produced. Surprisingly, between 10 and 29 percent of the resin produced by smoked cannabis is the result of terpenes. More than 200 terpenes have been identified in cannabis.
Macro shot of cannabis. The resinous stalks that appear to shimmer are trichomes.
In 1997, the Swiss Federal Research Station for Agroecology and Agriculture conducted a study entitled Essential oil of Cannabis sativa L. strains. The study investigated 16 terpenoids found in different cannabis strains. The terpenes found in the highest concentrations included alpha-pinene, limonene, trans-caryophyllene, and myrcene.
- Alpha-pinene: Also found in rosemary, sage, and pine trees, alpha-pinene is reported to increase mental focus and energy. It is also an expectorant and a bronchodilator. In addition, it can be used as a topical antiseptic. As its name implies, it is found in the greatest quantities in cannabis samples that emit a pine tree-like odor or that of rosemary or sage.
- Limonene: This terpene is found in cannabis that has a citrus smell (think oranges and lemons). It is believed to deliver relaxing effects and is known to have anti-bacterial, anti-depressant, and anti-carcinogenic properties. However, the efficacy of limonene goes even further; it quickly permeates cell membranes and helps other terpenes gain entry into cells. In this respect, it modulates the effect of other terpenes and can result in a more potent effect for a variety of terpenes (and cannabinoids). Its anti-carcinogenic and anti-fungal properties may help protect cannabis smokers from fungi and carcinogens in cannabis smoke (and may be why life-long cannabis smokers don’t seem to get lung cancer).
- Trans-caryophyllene: Has been found to provide protection to the nervous system, including brain cells. Researchers at Korea University discovered that it can be an effective treatment for stroke sufferers and may even play a preventative role in strokes. Like a variety of cannabinoids and the terpene myrcene (see below), trans-caryophyllene has also been found to have a powerful analgesic effect.
- Myrcene: This terpene is more common in indicas than sativas. Myrcene is a constituent element of menthol and citronella and is arguably the most cited terpene. It offers many therapeutic effects, including relaxing muscles and killing pain. It is also an anti-depressant and anti-inflammatory. Like limonene, myrcene has an effect on the permeability of cell membranes, meaning it can act as a regulator of other terpenes and cannabinoids, enhancing or buffering (reducing) their effects. Because myrcene is present in mangos, it is responsible for the urban legend that consumption of mangos before smoking cannabis will enhance the effects of the THC in the herb. Whether the potency of myrcene commonly found in mangos is sufficient to enhance the potency of the psychoactive effects of marijuana remains uncertain.
Terpenes Play Trans Cannabinoids
Beta-caryophyllene (BCP) is a terpene that fits into the CB2 cannabinoid receptors in the immune system. It produces a non-psychoactive anti-inflammatory effect. Because it binds to a cannabinoid receptor, beta-caryophyllene is often categorized as a cannabinoid.
How to Identify Terpenes
This post was originally published on June 17, 2015, it was updated on October 5, 2017.