Terpenes

Terpenes are organic compounds that provide the aroma and flavor in cannabis and a variety of other organisms, mostly plants. Terpenes are the primary components of essential oils. They are also responsible for the aroma and flavors of cannabis and influence its effects by interacting with cannabinoids. Terpenes form inside cannabis trichomes, and their relative presence is directly affected by both the spectrum and intensity of light exposure.

More about terpenes

Terpenes are aromatic compounds responsible for the unique aroma of each cannabis cultivar. The appealing aromas and flavors consumers enjoy when smoking, dabbing, or vaping cannabis are all thanks to terpenes. Each cannabis cultivar has its own unique aroma because it has its own distinct terpene content. Whether you smoke cannabis flower, dab concentrates, or vaporize either, these molecules are hard at work delivering tasty citrus, diesel, woody, pine, skunky, coffee, spicy, herbal, or tropical flavors to your palate.

How terpenes interact with the human body

Terpenes do more than provide flavor and aroma. They also support other cannabis compounds in producing desired effects. This is called the entourage or ensemble effect, and it's the reason these aromatic compounds have become such a critical area of cannabis research. 

Whether consuming cannabis for personal or medical use, consumers are most interested in the effect cannabis will deliver. The entourage effect suggests that the right cocktail of cannabis compounds will prove more potent and effective than an isolated compound.

Terpenes and cannabinoids may either exaggerate or suppress one another's effects, depending on which combination is present in a given cultivar and how an individual responds to it. Mounting scientific evidence suggests that terpenes play a considerable role in not only tempering the intoxicating effects of THC, but also creating synergy with other cannabinoids and even increasing their therapeutic value.

A huge factor in the cannabis industry's current terpene boom is the growing popularity of dabbing — the act of inhaling vaporized cannabis concentrates through a temperature-specific heating method such as a dab rig, e-rig, or vaporizer. Dabbing concentrates typically results in a smooth, tasty, potent cannabis experience. Many dabbers may not be aware of the possibility that terpenes produce toxic chemicals when heated to high temperatures. According to a study from Portland State University, vaporizing terpenes at the high temperatures common in dabbing may produce the toxicants methacrolein and benzene, which have been linked to certain cancers. So, if you want to enjoy a flavorful dab without heating the terpenes to toxicity, dab at as low a temperature as possible. Between 380 and 420 Fahrenheit (193 and 215 Celsius) is generally considered the low-temp dabbing sweet spot where concentrates vaporize and cannabinoids are activated but terpenes are burned away.

Prominent terpenes

Although hundreds of different terpenes have been found in cannabis, only a select group of them are sufficiently present to warrant mention. These are the 11 most prominent terpenes in cannabis, along with their aromas, boiling points, and potential health benefits as shown in experiments on animals.

Myrcene

Photo by: Gina Coleman/Weedmaps

Myrcene is one of the two most prominent terpenes in cannabis — the other being caryophyllene — meaning most cultivars on the market are dominant in one or both. It is also found in lemongrass, thyme, and mango, and carries the signature earthy aroma found in most cannabis plants. Its boiling point is 332 degrees Fahrenheit (167 Celsius). Similar to several other cannabis compounds, myrcene may be an effective anti-inflammatory, pain medication, and antioxidant, according to a study published in 2020 in the International Journal of Immunopathology and Pharmacology.

Caryophyllene

Beta-caryophyllene is another predominant terpene found in cannabis. It has a boiling point of 266 degrees Fahrenheit (130 Celsius). In addition to cannabis, caryophyllene is found in hops, cloves, and rosemary. It carries an herbal aroma synonymous with these plants. Like myrcene, caryophyllene has both anti-inflammatory and pain-relieving properties, as well as wound-healing abilities, at least in animal models.

Pinene

Pinene is one of the most commonly expressed terpenes in all of nature. Most famously found in pine trees and other conifers, pinene is also responsible for the piney aroma of certain cannabis cultivars. Pinene also has displayed anti-inflammatory properties in cultured human cells, and it may help prevent ulcers and improve airflow to the lungs. It has a boiling point of 311 degrees Fahrenheit (155 Celsius).

Limonene

In addition to cannabis, limonene is most commonly found in citrus fruits where it provides that fresh citrus smell. It has a boiling point of 349 degrees Fahrenheit (176 Celsius). Limonene is frequently used in a wide variety of natural products, such as fragrances and cleaning supplies, leading some cultivars to be named after and described as smelling like cleaners. A comprehensive review of existing studies published in the Journal of Food Biochemistry in 2021 showed that limonene has anti-inflammatory, antioxidant, and anticancer properties, and it protects cardiovascular, liver, and gastrointestinal tissues in humans.

Terpinolene

Terpinolene boasts a fresh piney, herbal-citrus aroma and has a boiling point of 366 degrees Fahrenheit (186 Celsius). It's commonly found in plants known for pleasant fragrances such as cumin, cardamom, tea tree, oregano, and apples.

Humulene

Humulene is a common cannabis terpene that's predominant in hops. It's also present in sage, clove, basil, black pepper, and ginseng, and carries a corresponding hoppy aroma. Research has indicated that humulene may be an effective topical anti-inflammatory and pain reliever in mice. It has a boiling point of 222.8 degrees Fahrenheit (106 Celsius).

Linalool

Linalool is found in rosewood, bergamot, coriander, rose, jasmine, and lavender. It has a boiling point of 388 degrees Fahrenheit (198 Celsius). It carries a very pleasant floral aroma, and is often used in soaps and perfumes. In addition to potentially reducing inflammation and inflammatory pain like several other terpenes, linalool has some unique potential health benefits. It's been found to inhibit the growth of fungal infections outside the human body, particularly as they arise from the yeast infection candida. It also has sedative, anti-anxiety, and anticonvulsant effects.

Ocimene

Ocimene has a strong, sweet, herbal scent and a boiling point of 122 degrees Fahrenheit (50 Celsius). It's found in a wide variety of plant life, including mint, mango, parsley, tarragon, basil, and orchids. Omicene can act as an anti-inflammatory and may have antiviral and antifungal properties.

Nerolidol

Photo by: Gina Coleman/Weedmaps

Nerolidol is characterized by a fresh woody aroma. Also called peruviol and penetrol, nerolidol can be found in lavender and jasmine. It is used in a wide variety of cosmetic and cleaning products and has a boiling point of 252 degrees Fahrenheit (124 Celsius). It may help other drugs penetrate the skin for more effective topical delivery. 

Bisabolol

Bisabolol has a mild floral scent, making it a common ingredient in fragrances and cosmetics. It has a boiling point of 307.4 degrees Fahrenheit (153 Celsius). Bisabolol has long been thought to heal the skin. Animal studies have shown that bisabolol may specifically reduce skin inflammation.

Guaiol

Guaiol is found in guaiacum and cypress pine. It has a quintessentially piney aroma, and a boiling point of 197.6 degrees Fahrenheit (92 Celsius). Guaiol has been identified as a potential antimicrobial in lab studies, as well as an inhibitor of lung cancer cell growth. Guaiol is also a central component of essential oils in Xylopia sericea fruits that have potential antibacterial and antioxidant properties.

The nose knows

Cannabis cultivated and cured to the highest standards typically exhibits a pungent yet pleasant aroma. Flowers emitting a strong fragrance are commonly referred to as “dank” or “loud.”

Aroma and flavor are subjective, and different aromas will appeal to different people, but some of the most popular strains smell like skunk, diesel, and pine. Grassy is often used to describe the smell of low-quality flower, but a grassy aroma doesn't necessarily denote poor quality. A distinct, pungent, and unmistakable aroma — regardless of its particular flavor — is evidence of terpenes hard at work within the cannabis plant.

Find the perfect strain for you and filter Weedmaps' strain catalog by flavor.

Other terpene sources and how they compare to cannabis

Terpenes are the primary components of essential oils — aromatics responsible for a plant's regeneration, oxygenation, and immunity defense. Essential oils, extracted from a variety of plants and foods, have been used for medicinal purposes for thousands of years. 

There's no recognizable difference, for example, between isolated caryophyllene from hops or from cannabis. However, there is a difference between the other compounds at play in cannabis. Further research is needed to know exactly how the effects of cannabis terpenes compare with terpenes from other sources, but it's clear cannabis terpenes support other cannabis molecules in producing desired effects.

Where are terpenes found on the cannabis plant?

You've probably noticed the tiny glandular hairs that cover the surface of cannabis plants, giving them a crystal-like sheen and sticky feel. They're called trichomes, and they're responsible for terpene production in cannabis. Trichomes contain resin glands that make terpenes and cannabinoids such as tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA), which turn into tetrahydrocannabinol (THC) and cannabidiol (CBD), respectively, when decarboxylated. In other words, almost everything a user wants from cannabis — including terpenes — are found in trichomes all over the plant's surface.

Photo by: Gina Coleman/Weedmaps

Terpenes vs. terpenoids: what's the difference?

As the popularity of these aromatic molecules has skyrocketed in the cannabis market, the terms terpene and terpenoid have become interchangeable. But there is a notable difference between the two. 

Terpenes are hydrocarbons — compounds made of hydrogen and carbon. When cannabis is dried and cured, terpene atoms are oxidized, and terpenes then become terpenoids.

Why does the plant produce terpenes?

Plants create terpenes to protect against herbivores, insects, and other environmental dangers. They're also responsible for a plant's regeneration and oxygenation. In light of these functions, it makes sense that some serve as potential immunity boosters in humans. It appears that terpenes may be providing immunity defenses in both the people who consume these aromatic compounds and the plants that produce them.

More than 200 terpenes have been discovered in the cannabis plant, but most of them are only present in such extremely low quantities that testing labs aren't even able to detect them. So why does the cannabis plant produce them all? 

Current research indicates several factors that may contribute to terpene diversity. Terpene synthases (TPSs) — enzymes responsible for creating the terpene structure — may either produce multiple terpenes from the same basic structure or provide pathways for the production of whole new terpenes. 

It's also possible that terpenes continue to diversify as part of an escalating defense against natural enemies that will evolve and diversify their counter-defenses in the future. Terpene diversity may also be a result of human intervention. Or, more accurately, the chemical differences we see in cannabis may be driven by extensive cultivation and breeding for a variety of desired traits.

How growing, harvesting, and curing conditions affect terpene expression

Terpene preservation has never been more important to the cannabis market than now. Growing, harvesting, and curing conditions all have an effect on terpene expression, and they can all contribute to the terpene-heavy cultivars that today's cannabis consumers are looking for.

Growing cannabis plants indoors will give a grower greater control over environmental factors that either contribute to or detract from a plant's terpene expression. Indoor growers will be familiar with hydroponics, or methods of growing plants in a nutrient solution and water system instead of soil. 

While a hydroponic grow won't necessarily inhibit terpene expression, growing in traditional soil is an easier way to ensure a prominent terpene profile. An excess of nutrients may also inhibit terpene expression, which growers can combat by reducing nutrient intake during the final week or two before harvest.

Growers who want to get a rich terpene profile out of their plants should neither harvest too early nor too late. Harvesting too early may cut trichomes off from full cannabinoid and terpene production, while harvesting too late may produce trichomes that have decreased in chemical potency, or broken off entirely. Properly ripe trichomes will be bold, distinct, and translucent on the plant's surface, and they'll be rich in terpenes.

Chemotypes

There are many chemical phenotypes, or chemotypes, of cannabis out there. A cannabis chemotype represents the chemical profile of a cannabis plant, i.e., its cannabinoid and terpene ratios.

Chemotypes of cultivated varieties

Most cultivars on the market are predominant in either myrcene or caryophyllene. However, research into the chemotypes of today's cultivars suggests that one cultivar does not necessarily express just one chemotype, but rather, may exhibit a spectrum of chemotypes. In other words, two plants of the same cultivated variety may have slightly different chemical expressions. These findings actually tell us a lot about the obsolescence of our current cannabis taxonomy — namely, the indica/sativa/hybrid classification model.

The terms indica and sativa were originally used to describe a cannabis plant's physical traits and geographic origin, not its chemical makeup. Furthermore, the indica/sativa taxonomy was established long before we knew anything about cannabis terpenes and the enormous variety of chemotypes implicated by their presence in the cannabis plant. Their inception also came long before intensive breeding utterly diversified the chemical makeup of the cannabis plant. 

An in-depth study on terpene and cannabinoid expressions in a wide range of plant samples concluded that classifying cannabis by its terpene and cannabinoid contents would be more effective in identifying the best medical uses for a given cultivar.

Chemotypes of landrace varieties

Landrace varieties are cannabis plants grown in their native environments and geographical regions. Acapulco Gold, Panama Red, and Durban Poison are examples of original landrace strains that were domesticated for traditional cultivation. Terpenes found in naturally occurring cannabis include myrcene, caryophyllene, humulene, limonene, and pinene. The common expression in landrace strains probably means they represent the terpene profiles that nature intended before humans started intensive breeding.

Products

Concentrates and isolates

Concentrates have taken the cannabis world by storm in recent years, largely because of their terpene-rich content and subsequent spectrum of juicy flavors. Cannabis concentrates contain all of the most desirable properties from cannabis trichomes — namely cannabinoids and terpenes — in one product. You may have either heard of or enjoyed full-spectrum extracts, sauce, or distillate. All of these are forms of cannabis concentrates.

Isolates, or extractions of a single cannabinoid or terpene, have also become more prominent in the arena of natural medicine. The possibility of individual terpene extraction has led to a variety of isolate products that aim to reap specific medicinal benefits. 

Re-infusion

Terpene extraction isn't only exploited to create isolates. Once extracted, natural terpenes are also re-infused into cannabis goods, primarily for flavor. Oil cartridges — containers filled with concentrated cannabis for vaping — often include re-infused terpenes. Because the process of making distillate for vape cartridges removes all the natural plant terpenes, some extractors blend terp sauce — a cannabis extract composed of over 50% terpenes — with raw distillate to produce strain-specific vape cartridges.

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