Cannabis Terpenes: Learn how plants produce them and the TOP 10 most abundant terpenes in cannabis
Enjoying the aromas and effects of the different varieties of cannabis with their distinctive combinations of terpenes is a time-honored tradition for cannabis users and breeders worldwide.
Terpenes are major components of marijuana resin, just as they make up the largest percentage of aromatic essential oils contained in most plants. The scent of most flowers, herbs and spices are composed of these oils. You recognize the presence of terpenes when you pinch that bud and take a whiff. Grapefruit, Silver Haze, Blueberry, Real Skunk—each of these odors brings a recognition of the type of high that the sample will explode into your brain. These odor molecules increase as the plant’s investment in reproduction increases. Before flowering, the odors are faint. As flowering progresses and the plant is more invested in protecting it, the odor grows. As the bud ripens, whether seeded or sinsemilla (un-pollinated), the odor increases substantially.
As marijuana matures sexually, it produces terpenes in the glands that surround the flowers
Terpene levels increase during the dark period and reach their peak just before dawn. During the day they evaporate and fill the surrounding air with odor to warn predators. By the end of the day, at dusk, terpene (and cannabinoid) levels are at their lowest.
Most of the aromas that we associate with plants are the result of terpenes and flavonoids. Humans can smell and taste these compounds, but that is not the only way they affect us. While terpenes affect the brain in their own way, they also modify the effect of THC within the brain, adding subtleties to the high.
By temporarily altering brain function, terpenes can affect mood, sensitivity, and perceptions, including balance and pain.
Some terpenes may affect the high because they lock into receptor sites in the brain and modify its chemical output. A few, such as thujone, one of the main terpenes in wormwood (which is used to make absinthe), bind weakly to the CB1 receptor. Others alter the permeability of cell membranes or the blood brain-barrier, allowing in either more or less THC. Others affect serotonin and dopamine chemistry by shutting off their production, affecting their movement, binding to their receptor sites, or slowing their natural destruction.
By temporarily altering brain function, terpenes can affect mood, sensitivity, and perceptions, including balance and pain. When terpenes are mixed, as they are in natural plant oils, they each play a role in affecting brain function. Some combinations may work synergistically and others antagonistically, but each “recipe” of terpenes affects moods and feelings in its own way.
Over 100 terpenes have been identified in marijuana
There are actually many more when one considers the multiple variations of each terpene. For instance, the characteristic citrus odor found in fruit rinds differs by type and even variety of fruit—oranges and lemons have different odors, and their terpenes, called limonenes, are mirror versions of each other. This is due to slight differences in the amounts of limonene, as well as other compounds that contribute to citrus elements.
Terpenes are produced in the trichomes, the same glands where THC is produced.
About 10-30% of marijuana smoke resin is composed of assorted terpenes. Some terpenes appear only occasionally in marijuana, while others are found all the time. The percentage of particular terpenes and the ratios in which they are found vary by plant variety. You experience this yourself when you notice different varieties have specific smells, indicating their individual essential oil makeup. One researcher found that the oil of common black pepper (piper nigrum) also has a group of terpenes similar to cannabis. Terpenes are produced in the trichomes, the same glands where THC is produced.
Marijuana plants have more terpenes at the end of the dark period than after a full day of light.
Age, maturation, and the time of day can affect the amount, and perhaps ratios, of terpenes. One reason is their high evaporation rates at temperatures as low as 75° F (24° C). As plants mature, their odor gets more intense and sometimes changes as they ripen. Plants are constantly producing terpenes, but they evaporate under pressure from sunlight and rising temperatures. That means plants have more terpenes at the end of the dark period than after a full day of light. You can test this yourself— check a plant’s odor early in the morning and at the end of a sunny day. You will find more pungency earlier in the morning.
Climate and weather also affect terpene and flavonoid production. The same variety of marijuana can produce different quantities and perhaps even different types of oils, depending on the type of soil in which it is grown, or the fertilizers used.
Here are 10 terpenes generally most abundant in cannabis
Individual plants may differ widely both in total percentages of terpenes and in their ratios
Myrcene is the most prevalent terpene found in most varieties of marijuana. It is also present in high amounts in hops, lemon grass, West Indian bay tree (used to make bay rum), verbena and the plant from which it derives its name, mercia. Myrcene also appears in small amounts in the essential oils of many other plants. Its odor is variously described as clove-like, earthy, nutty, green-vegetative, and citrus. The various odors are the result of slight differences in the overall essential-oil makeup. All of these flavors and odors are commonly used to describe cannabis.
Slightly overripe mangos contain large quantities of myrcene. Eating a mango 20- 30 minutes before using marijuana gives the myrcene time to enter the bloodstream and start crossing the blood-brain barrier. Myrcene may help THC cross the barrier by opening the pathway or less likely, it might carry the molecule with it. The combination of THC and myrcene creates a stronger high, faster.
Limonene is found in the rind of citrus and many other fruits and flowers. Limonene is the second, third or fourth most prevalent terpene in cannabis resins, depending on the variety. Everyone is familiar with the odor of citrus resins—they explode into the air when a fruit is peeled. The exact odor is determined by the structure of the terpene.
Limonene has anti-bacterial, anti-fungal and anti-cancer activities. Since limonene is such a potent anti-fungal and anti-cancer agent, it is thought to protect against the Aspergillus fungi and carcinogens sometimes found in cannabis smoke streams. It synergistically promotes the absorption of other terpenes by penetrating cell membranes. In humans, limonene’s design facilitates a direct response by quickly permeating the blood-brain barrier. The result is increased systolic blood pressure. In one test, participants reported an increase in alertness and restlessness. Various limonene analogs can cue the brain to sexuality, buoyancy or focused attention. Limonene sprays are used to treat depression.
B-Caryophyllene is a major terpene found in black pepper (15-25%), clove (10-20%) and cotton (15-25%). It has a sweet, woody, dry-clove odor and tastes pepper-spicy with camphor and astringent citrus backgrounds. It contributes to black pepper’s spiciness and is used industrially to enhance tobacco flavor.
B-Caryophyllene, ingested in large amounts, blocks calcium and potassium ion channels. As a result, it impedes the pressure exerted by heart muscles. Applied topically, it is an analgesic and is one of the active constituents of clove oil, a preferred treatment for toothache. It docks on the CB2 receptor site, the same site for which cannabidiol has an affinity. Thus, it may help reduce inflammation. It added a slightly woody taste to the bouquet.
Pinene is the familiar odor associated with pine trees and their resins. It is found in many other plant essential oils in noticeable amounts; including rosemary, sage and eucalyptus.
Pinene is likely to give the true skunk varieties, ones that stink like the animal, much of their odor.
Terpineol has a lilac, citrus, or apple blossom/lime odor. It is a minor constituent of many plant essential oils. It is used in perfumes and soaps for fragrance. Terpineol is obtained commercially from processing other terpenes.
Borneol smells much like the menthol aroma of camphor and is easily converted into it. It is found in small quantities in many essential oils. Commercially, it is derived from artemisia plants such as wormwood and some species of cinnamon. The camphor-like overtones of Silver Haze varieties are unmistakable.
Delta-3-Carene has a sweet, pungent odor. It is a constituent of pine and cedar resin but is found in many other plants, including rosemary. It may contribute to the dry eye and dry mouth experienced by marijuana users.
Linalool has a floral scent reminiscent of spring flowers such as lily of the valley, but with spicy overtones. It is refined from lavender, neroli and other essential oils. Humans can detect its odor in the air at rates as low as one part per million (ppm). It is a component of several sedating essential oils.
Pulegone has a minty-camphor odor and flavor that is used in the candy industry. It is found in tiny quantities in marijuana.
Cineol is the main ingredient in oil of eucalyptus. It has a camphor-minty odor similar to pulegone. It is also found in other fragrant plants and in minor amounts in marijuana.
Just as there is no single best flavor of ice cream that everyone agrees to, there is no single best mixture of terpenes. Individual tastes, preferences, and circumstances all influence what terpene profile would be the best for a given person at a given time. However, if there are scents that are favored or despised, paying attention to terpenes can point one in the right direction toward the right sorts of cannabis for them.