Of the many active ingredients in marijuana, cannabinoids — the miracle molecules that deliver most of the medical efficacy of marijuana — are not the whole picture. Some cannabis consumers may be aware of terpenes, the cannabinoid-like chemicals that give herb such a pungent aroma.
What most do not know is that terpenes also deliver therapeutic relief, just like their cannabinoid cousins.
Terpenes are produced in special secretory cells within 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 created. About 20,000 terpenes exist in nature; more than 200 have been identified in cannabis (compared to 111 cannabinoids).
Like amino acids, terpenes 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.
Beyond odor, terpenes play several roles, including protecting the cannabis plant against predators like insects and animals. These special molecules constitute roughly 10 to 20 percent of the total pre-smoked resin in the trichome. It is estimated that 10 to 30 percent of smoke resin produced by marijuana comes from terpenes.
Myrcene, one of the most common terpenes in cannabis, produces earthy, balsamic, spicy, and clove-like odors. According to a 1997 study in Switzerland, it is the most abundant terpene in cannabis, sometimes composing up to 50 percent of the terpene volume in a cannabis plant. More important, myrcene has been found to be a precursor to many other terpenes in cannabis, meaning it helps form them.