In addition to Cannabinoids, cannabis also contains so-called terpenes. These are responsible for the smell and taste of the strain, but they also have medicinal potential. They are thought to have a strengthening and moderating effect on the effects of cannabinoids. Current research seeks to understand the terpenes contained and their effect on humans in order to optimise the therapeutic effects of cannabis. In this article you will find information on the most common cannabis terpenes, what current research suggests they are used for and how they can be identified.
What are terpenes?
Terpenes are organic substances found in all plants. They are not essential for the survival of a given organism, but they can perform a number of useful tasks. They are therefore classified as secondary plant substances. Terpenes are a very diverse group of chemical compounds with a correspondingly wide range of properties. The most common feature of terpenes is their isoprene-based backbone. (1)
Terpenes may be responsible for the plant's external appearance, taste and smell, among other things. In nature, they sometimes function to attract insects to promote reproduction or repel pests. For example, the characteristic smell of conifers and other plants is caused by terpenes in the forest. The smell of grasses, citrus fruits, mint and the scent of cannabis flowers is also based on a particular terpene structure. Terpenes can have different profiles of effects for humans, which are used in aromatherapy and in different varieties of cannabis. (2)
Terpene subspecies
If you ask about terpenes, you will sometimes come across the term terpenoids. The terms terpenoids and terpenes are often used interchangeably. Strictly speaking, terpenoids are structures similar to terpenes, the peculiarity of which is that their chemical composition can be based on other components besides carbon and hydrogen, unlike pure terpenes.
In addition, terpenes are divided into four categories:
Monoterpenes
Diterpenes
Triterpenes
Sesquiterpenes
They denote the amount of chemical building blocks that make up a given terpene. Monoterpenes (e.g. myrcene, pinene and linalool) and sesquiterpenes (e.g. humulene and bisabolol) are of particular importance for medicinal uses. Many plants produce them in large quantities and they are the raw material for the production of essential oils (3).
Terpenes and cannabis: The Accompanying Effect
Terpenes have no direct psychoactive effect. However, they may help to increase or decrease the intoxicating effect of THC. This is known as an additive effect.
The entourage effect refers to the effects of a substance that are not the result of the sum of the individual effects, but of the combination of components (here: cannabinoids and terpenes) and their specific effect profiles.
In addition to the prospect of modulating the intoxicating effects of THC through a specific terpene profile for medical benefit, current research is considering other medical benefits that could result from the targeted application of the entourage effect.
These may include stronger and/or faster symptom relief, elimination of side effects, but also new effects that are beneficial to the course of cannabis treatment. However, the exact nature of this effect and its potential application require further research (4).
Terpenes in vaporisation
In the vaporisation of medicinal cannabis products, the active substances contained in the product are vaporised by heat and then inhaled. It should be noted that terpenes, like all other constituents, require their own temperature thresholds in order to be absorbed in the vapour and inhaled. This means that a minimum temperature is required for the complete release of all contained terpenes. Conversely, some terpenes can be excluded from the effect by keeping the product below the appropriate temperature threshold during vaporisation. The upper limit for consumption of medicinal cannabis is 230 °C. At this temperature the combustion process begins.
This means that some of the ingredients (including terpenes) will burn without any effect. At the same time, harmful substances are released during combustion which, if consumed over a long period of time, lead to lung and respiratory problems. Terpenes that do not take effect until temperatures of 230 °C (e.g. geraniol, which is rarely found in cannabis) are therefore unsuitable for medical use. In addition, some terpenes may prove harmful if patients suffer from certain allergies. Before starting treatment with cannabis, allergy sufferers should consult their treating physicians and pharmacists for more detailed information on terpene profiles and possible intolerances (5).
Terpenes in medicinal cannabis
To date, approximately 400 different terpenes have been identified in different medicinal cannabis strains. Research is ongoing to determine their effect on the human body. Some of the most well-known terpenes and their effects can be found in the following list.
Bisabolol: Bisabolol has a slightly sweet taste reminiscent of chamomile. It is associated with pain-relieving effects, is said to soothe skin irritation and has anti-inflammatory effects. Bisabolol can be inhaled at temperatures as low as 153 °C. (6)
Borneol: Borneol has a mild minty flavor and is associated with a calming and stress-reducing effect that may have an anxiety-reducing effect on patients. It can be inhaled from 210 °C in a vaporizer. (7)
Caryophyllene: This terpene is found in cannabis, but also in cloves and cinnamon. It can be recognised by its spicy tone. Caryophyllene is said to relieve symptoms of depression, but it also has anti-inflammatory and antibacterial properties. Caryophyllene evaporates in a vaporizer from 130 °C. (8)
Eucalyptol: Eucalyptol is partly responsible for the refreshing effect of eucalyptus. It is also said to have a calming effect, relieving pain and positively affecting circulation. The terpenes of eucalyptol evaporate at a temperature of 177 °C. (9)
Humulen: Humulene is especially known for giving hops an earthy flavour. It is reported to relieve inflammation and pain. It also has antibacterial properties. There are also studies that suggest an appetite suppressant effect. A temperature of 106 °C is required to release humulene. (10)
Limonen: Limonene has a major effect on the taste and aroma of citrus fruits or plants associated with them. Limonene may have an anxiolytic effect and counteract depressive symptoms with a mood-enhancing effect. The temperature required to release limonene is 176 °C. (11)
Linalool: Linalool terpenes have a floral scent. They are said to have a relaxing and sleep-inducing effect. Linalool may also have an anxiolytic effect. It evaporates in a vaporizer from a temperature of 198 °C. (12)
Myrcen: Myrcene is often only present in small amounts in cannabis. It produces an earthy flavour and can help improve mood and relieve anxiety. There is also evidence that myrcene has antibacterial and antifungal properties. In addition, the terpenes of myrcene in cannabis may optimize the effect of the THC it contains. A temperature of 167 °C is required to activate myrcene. (13)
Ocimen: Ocimen has a blend of pine and citrus flavours. It is often found together with myrcene. It is reported to have anti-inflammatory properties. Ocimene evaporates at temperatures as low as 66 °C. (14)
Pinen: Pinenic terpenes are named after the distinctive pine scent they give off. They are said to have anti-inflammatory properties and stimulate various brain activities related to creativity and memory. In vaporisation, a temperature of 155 °C is required to activate pinene. (13)
Terpinol: Terpinol is found in cannabis, apples, lime blossom and lilac, among others. It is associated with calming, antifungal and antibacterial properties. Terpinol requires a temperature of 185 °C to evaporate. (15)
Valenciennes: This terpene produces a sweet aroma and is known primarily for its dermatological properties. It can have a healing effect on skin damage and prevents the formation of fungi. Valencene evaporates from 123 °C. (16)
Terpenes and cannabis for medicinal use
As terpenes have no intoxicating properties in themselves, they are not subject to the Narcotic Drugs Act. The possession and use of medicinal terpenes, for example in spray form, is not subject to any special requirements.
However, the combination of cannabinoids and terpenes within cannabis flowers and medicinal cannabis preparations to achieve an accompanying effect and strain-specific effect profile is only legal with a prescription.
Anyone wishing to buy cannabis terpenes or take terpenes through cannabis therefore needs a doctor's prescription. The requirements for cannabis treatment can be found in our article.
In principle, all treating doctors are entitled to prescribe medical cannabis if (in their opinion) it can alleviate a diagnosed condition. Health insurance companies cover the cost of cannabis treatment if patients have reached the end of their treatment. Otherwise, they must cover the cost (€5-15 per gram) themselves. (17)
Does health insurance cover the cost of medical cannabis?
In the UK, health insurance typically does not cover the costs of medical cannabis. The availability and coverage of medical cannabis are subject to strict regulations, and it is only legally available through a prescription from a specialist doctor in very specific cases, such as severe epilepsy, chemotherapy-induced nausea, or multiple sclerosis symptoms.
Even though medical cannabis was legalized in the UK in 2018, it is considered a last-resort treatment when conventional medications fail. As a result, most private health insurance providers do not cover medical cannabis because it is not widely recognized as a standard treatment within the National Health Service (NHS) or private healthcare systems.
Patients who obtain prescriptions often have to pay out-of-pocket, as insurers typically exclude coverage for treatments not endorsed by the NHS or widely accepted medical guidelines. However, some insurance policies might consider coverage on a case-by-case basis, depending on the specific medical need and policy terms.
Reference:
Cox-Georgian, D., Ramadoss, N., Dona, C., & Basu, C. (2019). Therapeutic and Medicinal Uses of Terpenes. Medicinal Plants: From Farm to Pharmacy, 333-359.
Ashour, M., Wink, M. & Gershenzon, J. (2010). Biochemistry of Terpenoids: Monoterpenes, Sesquiterpenes and Diterpenes. Annual Plant Reviews, 40, ch. 5.
Ferber SG et al. (2020). The Entourage Effect. Terpenes Coupled with Cannabinoids for the Treatment of Mood Disorders and Anxiety Disorders. Current Neuropharmacology, 18(2), 87-96.
Eyal, A. M. et al. (2023). Vapor Pressure, Vaping, and Corrections to Misconceptions Related to Medical Cannabis' Active Pharmaceutical Ingredients' Physical Properties and Compositions. Cannabis and Cannabinoid Research, 8(3), 414-425.
Eddin, L. et al. (2022). Health Benefits, Pharmacological Effects, Molecular Mechanisms, and Therapeutic Potential of α-Bisabolol. Nutrients, 14(7), 1370.
Cao, B. et al. (2018). (+)-Borneol suppresses conditioned fear recall and anxiety-like behaviors in mice. Biochemical and Biophysical Research Communitcations, 495(2), 1588-1593.
Bahi, A. et al. (2014). β-Caryophyllene, a CB2 receptor agonist produces multiple behavioral changes relevant to anxiety and depression in mice. Physiology & behavior, 135, 119-124.
Jun, Y. S. et al. (2013). Effect of Eucalyptus Oil Inhalation on Pain and Inflammatory Responses after Total Knee Replacement. A Randomized Clinical Trial. Medicinal Plants in the Prevention and Treatment of Chronic Diseases, 2013.
Tang, M. et al. (2022). Antidepressant-Like Effect of Essential Oils from Citrus Reticulata in Reserpine-Induced Depressed Mice. Natural Products Communications, 17(5).
Karimian, P. (2014). Anti-oxidative and anti-inflammatory effects of Tagetes minuta essential oil in activated macrophages. Asia Pacific Journal of Tropical Biomedicine, 4(3), 219-227.
Huang, J. et al. (2020). Antibacterial activity and mechanism of three isomeric terpineols of Cinnamomum longepaniculatum leaf oil. Folia Microbiologica, 66, 59-67.
Zhang, L. et al. (2023). Production, Function and Applications of the Sesquiterpenes Valence and Nootkatone: A Comprehensive Review. Agricultural and Food Chemistry, 71(1), 121-142.
