Within the last 100 years, cannabis has played numerous roles in American society. From the pre-prohibition days of the 19th and early 20th centuries to the dark ages of recent decades, cannabis has occupied a place in both the limelight and shadows. As a result of 80+ years of prohibition, academic research on cannabis as a viable medicine has been largely curtailed. With the recent wave of legalization bills sweeping across the country, there has been a renewed interest in the possible benefits of cannabis and the cannabinoids and terpenes found in the trichomes.
To get an idea of where terpene science is today, we spoke with Dr. Susan Trapp, a plant microbe bio-scientist who has been called ‘The Queen of Terpenes’ by many within the academic cannabis community. While terpenes are often associated with cannabis, they are actually the largest class of molecules within plants in general. In fact, the essential oil and aromatherapy industries are centered around terpenes. Dr. Trapp’s research has shown that there are tens of thousands of terpenes and terpenoids in nature beyond what’s in cannabis. [1]
From the Herb Cabinet to Industry
Terpenes delicately and strongly contribute to the aromas and flavors of plants that we love to smell and eat, like basil or hops or jasmine. By their simplest definition, “terpenes are your herb cabinet” as Dr. Trapp put it. Academic investigations into whether cannabis-derived terpenes offer viable medicinal properties has gained traction. Add in the volumes of studies regarding terpenes from other botanicals and the essential oils used in aromatherapy, and the stack of scientific papers on terpenes blossoms all the more.
With Dr. Trapp’s past research on terpenes, it’s fitting that she would transition to the modern cannabis industry where the terpene no longer is relegated as a waste by-product. Rather, terpenes are increasingly showing potentiation (ensemble effect) with cannabinoids, especially when considering patient feedback. Describing her passion behind working with terpenes, Dr. Trapp added, “I’m a naturalist at heart, utilizing things as nature provides them.” Indeed, cannabis has a diverse number of potential uses making cutting-edge research and product development more exciting.
While clinical studies using terpenes are predominantly in their early stages (there are some out there), the private sector has been including terpenes in commercial products for over a century — one of the oldest examples being turpentine. Terpenes have been used in the mint, perfume, and chewing gum industries. They provide natural, pleasing flavors for the food and beverage industries, while providing natural insecticides to, in turn, protect the plants that produce them. However, the singular focus of terpenes as commercial products has begun to shift — especially within the cannabis industry.
Synthetic or Natural?
As a result of increased terpene research, one big question has come to the fore — synthetic terpenes versus cannabis-derived terpenes? While lab-derived terpenoids may be beneficial, there are also a lot of unknowns involved with manipulation of natural compounds.
“In the world of organic chemistry,” Dr. Trapp explained, “a specific molecule is still a molecule regardless of how it is derived. D-limonene extracted from oranges is the exact same compound as D-limonene synthesized in the laboratory.”
Mirror-Image Molecules
“In chemistry,” she continued, “there is a term called enantiomer isomers which essentially means that two molecules have identical physical properties but differ in stereochemistry; the two molecules are mirror images of each other. When creating synthetic terpenoids, it is not always possible to control the production for creation of both mirror images.”
Terpenes isolated from natural products may contain only one of the two mirror images, while synthetically made compounds may have both mirror images. “Although the actual chemistry is simply put chemistry, there are many unknowns to be explored when creating the synthetic terpenoid as opposed to a terpenoid that’s been isolated from a natural source, like a lemon.”
However, “there are many unknowns unless these compounds have been well studied,” Dr Trapp explained. “The most obvious is paying attention to chirality or stereochemistry of the synthetic terpenoid product; this means you can create two forms of the same compound that are mirror images of one another, like our hands.”
This can mean that only one form of a compound is active. “There are some textbook examples of this such as ibuprofen,” Dr. Trapp continued,” where only the S-form is an active analgesic, and the other form has no effect.”
Terpedia and Beyond
In addition to her interest in cannabis terpenes, Dr. Trapp has founded ancillary companies within the cannabis industry, one example being Terpedia, a comprehensive online encyclopedia for terpenes. With Terpedia, Dr. Trapp, along with co-founder Dr. Dan McShan, aims to develop sound science regarding terpenes by developing a large knowledge-base and precision formulations.
“Terpedia is a digital scientific encyclopedia of curated terpene knowledge,” Dr. Trapp explained. “We provide terpene formulations, recommendations, validation, and a terpene chemo profile evaluation SMART report for various projects. Our premier terpene knowledge base educates and services hemp farmers, hemp companies, cannabis-focused veterinarians, and cannabis patients seeking terpene blends to address specific medical ailments.”
Terpedia’s newest offering for hemp and other product companies includes an evaluation of a product through the lens of Terpedia’s proprietary research study platform. The aim of this platform is to study product effectiveness, and initial evaluations provide a roadmap for companies seeking scientific validation of a formulation at minimal cost compared to a robust clinical trial.
In addition to Terpedia, Dr. Trapp has also launched TreatmentX, an app and data analytics platform that aims to assist cannabis patients in developing effective treatments tailored to individual needs versus blanket treatments.
In conjunction with these information-based projects, Dr. Trapp also is a key member of EndoSyn.bio which focuses on the creation of a supplement that’s capable of developing a fermentation process for the endocannabinoid system. The project is currently in the pre-seed stage of funding but has shown great promise.
Throughout our conversation, it was apparent that Dr. Trapp is excited for the future of cannabis research and the value cannabis-derived terpenes can provide as medical treatments. There are still many unknowns regarding the future of cannabis-based treatments— particularly the question of legality. Unfortunately, the answers to these questions remain to be seen. Until then we can only wait and see what Dr. Trapp and other prominent researchers will discover.
“I am very optimistic about the future of the cannabis industry,” Dr. Trapp concluded, “particularly on the medicinal side. We are only beginning to understand the endocannabinoid system which encompasses the discovery of how all small molecules interact within the human body. And when it comes to terpenes, they are playing a much bigger role than we give them credit for.”
About Dr. Susan Trapp
Dr. Susan Trapp is a 20-year biotechnology expert with a vision to accelerate patient-centric cannabis and endocannabinoid discoveries through education and research. As a Plant-Microbe Bioscientist, Dr. Trapp held several roles in academia, government, and early-stage development within the biotech industry. Her scientific career took off after working alongside Dr. Craig Venter, a well-respected Scientist renowned for mapping and sequencing the Human Genome, which introduced a new era of medicine and advanced the field of DNA technology substantially.
Dr. Trapp shifted focus to the cannabis industry after examining the molecular evolution of plant and fungal terpenoids (terpenes) throughout her postdoctoral research. This research has led to a variety of peer-reviewed publications including terpenoid genomics, human genome, canine and breast cancer molecular biomarker identification.
Trapp earned her crown as the ‘Queen of Terpenes’ by serving as a scientific advisor and valued consultant for cannabis and hemp companies as they continue to navigate the function of terpenes in products. Motivated by her passion for education, Dr. Trapp utilizes her in-depth knowledge of terpenes to educate the cannabis community at conferences and conventions nationwide. Trapp also serves as an instructor for the Cannabinoid Industry Association’s accredited courses.
Since making the shift to cannabis, Trapp co-founded several ancillary cannabis companies and is a recent graduate of Canopy Boulder’s cannabis business accelerator program. Her current projects include launching two terpene and cannabinoid-focused startups: Terpedia and EndoSyn.bio.
When she’s not busy enlightening the cannabis community about the world of terpenes, you’ll find her biking, skiing, climbing, or hiking in Golden, Colorado. For more information about Dr. Trapp, or to get in contact with her, visit her website at http://susanctrapp.com/
Editor’s note, October 2026: This conversation was published in May 2021. The companies and projects described above, including Terpedia, TreatmentX and EndoSyn.bio, are as Dr. Trapp described them at the time. Her quoted answers are kept exactly as given; the section that follows sets out what the research shows now on the points she raised.
What the Evidence Says Now
Mirror images are real, and cannabis is a good example. Dr. Trapp’s central chemistry point holds: a molecule is the same molecule whatever its source, but terpenes often come in two mirror-image forms, and the source can decide which one you get. Cannabis shows it neatly. The terpene synthase enzymes characterized from cannabis produce (−)-limonene and (+)-α-pinene.[2] Sweet orange peel oil, by contrast, is mostly the opposite form, (R)-(+)-limonene, as our article on the two scents of limonene explains. Limonene taken from oranges and added to a cannabis product is therefore not quite the limonene the plant makes. Whether that difference matters to the body is, as she put it, one of the unknowns.
The ibuprofen example has a twist. She is right that only S-ibuprofen inhibits the COX enzymes behind pain and inflammation; R-ibuprofen “is not a COX inhibitor.” But in the body, 50–60% of a dose of R-ibuprofen is converted into the active S form.[3] So the inactive mirror image is not simply wasted. The body can change one form into the other, which is exactly why chirality has to be studied compound by compound.
Potentiation is still being argued out. The article’s description of terpenes “increasingly showing potentiation (ensemble effect) with cannabinoids” reflected the optimism of 2021. The laboratory evidence since then points in different directions. In one cell study, six common cannabis terpenes neither activated the CB1 or CB2 cannabinoid receptors nor changed THC’s activity at them.[4] In another, all sixteen terpenes tested activated CB1 at about 10–50% of THC’s level, and some combinations with THC produced more activation than THC alone.[5] In mice, four terpenes produced cannabinoid-like behaviors and added to the effects of a synthetic cannabinoid.[6] Different assays give different answers. Our look at what the entourage effect research has actually shown keeps the scoreboard: a handful of specific pairings tested properly, some positive, some not, and many never tested at all.
Human evidence is beginning to arrive. She was right that clinical studies were at an early stage. One of the clearest since is a 2024 controlled study in 20 healthy adults: inhaling d-limonene together with THC reduced THC’s anxiety and paranoia ratings at the highest combination tested, without changing THC’s other effects.[7] It is one pairing, one small trial, and short-term effects only. But it is the kind of evidence that patient feedback and formulation platforms cannot replace, and that the field now needs more of.
For another expert view on terpenes and formulation, see our conversation with Michael Backes. For the wider family, our terpene education hub has the map.
References
- Trapp SC, Croteau RB. Genomic organization of plant terpene synthases and molecular evolutionary implications. Genetics. 2001;158(2):811-832. [journal impact factor = 3.564; times cited = 406]
- Booth JK, Page JE, Bohlmann J. Terpene synthases from Cannabis sativa. PLoS ONE. 2017;12(3):e0173911. doi:10.1371/journal.pone.0173911
- Evans AM. Comparative pharmacology of S(+)-ibuprofen and (RS)-ibuprofen. Clin Rheumatol. 2001;20(Suppl 1):9-14.
- Santiago M, Sachdev S, Arnold JC, McGregor IS, Connor M. Absence of entourage: terpenoids commonly found in Cannabis sativa do not modulate the functional activity of Δ9-THC at human CB1 and CB2 receptors. Cannabis Cannabinoid Res. 2019;4(3):165-176. doi:10.1089/can.2019.0016
- Raz N, Eyal AM, Berneman Zeitouni D, Hen-Shoval D, Davidson EM, Danieli A, Tauber M, Ben-Chaim Y. Selected cannabis terpenes synergize with THC to produce increased CB1 receptor activation. Biochem Pharmacol. 2023;212:115548. doi:10.1016/j.bcp.2023.115548
- LaVigne JE, Hecksel R, Keresztes A, Streicher JM. Cannabis sativa terpenes are cannabimimetic and selectively enhance cannabinoid activity. Sci Rep. 2021;11(1). doi:10.1038/s41598-021-87740-8
- Spindle TR, Zamarripa CA, Russo E, Pollak L, Bigelow G, Ward AM, Tompson B, Sempio C, Shokati T, Klawitter J, Christians U, Vandrey R. Vaporized D-limonene selectively mitigates the acute anxiogenic effects of Δ9-tetrahydrocannabinol in healthy adults who intermittently use cannabis. Drug Alcohol Depend. 2024;257:111267. doi:10.1016/j.drugalcdep.2024.111267
Last updated October 2026 · Originally published May 24, 2021.
