What are Terps?
Also known as Terpenes, Terpes, Terpenoids…
Terps are scented oils that indicate features of the cannabis plant or product. They’re frequently referred to as terpenoids, or terpenes, too. Essentially they are a tea tree or lavender oil, naturally secreted by the plant. This repels insects that would otherwise damage the plant before it can reproduce. Terpenes simultaneously aid plants reproductive success by luring pollinators – and smokers – with captivating scents.
These scents differ depending on a chemovar’s genetics, and their abundance is influenced by a few environmental factors, such as light, heat, fertilizer, and nutrients. Some businesses will even add certain terpenes back to their product at the end of the production process, especially if they have been volatilised during production.
Note: The term ‘terpenes’ is less accurate; as it describes terpenoids after the drying process denatures them. These terms are often used interchangeably within the community.
Why do Terpenes Matter?
Terpenoids are essentially perfumes that give away a buds personality. From the scent that is released (a result of its terpene profile) you learn a little about a chemovar’s potency, its effects, taste, and even its cost (drugs and me, 2019). When we talk about a lemon haze smelling citrusy, we are talking about the scent of limonene, a terpene we recognise as giving lemons their signature citric scent.
The Science Behind Terpenes
There is a growing body of evidence that demonstrates the effects of terpenes. They have a long history of use across diverse industries. Whilst we might think they belong in an aromatherapy salon, some of their wide-ranging applications are surprising!
Terpenes are suspected to affect diverse neurological pathways in our brains. They enter the body both through percutaneous and non-percutaneous routes (A Prashar et al., 2004) so for example, merely touching and smelling a particularly oily bud, coated in linalool relaxes a person.
‘merely touching and smelling a particularly oily bud, coated in linalool relaxes a person.’
Limonene was found to change the concentrations of serotonin transmitters in the brains of model organisms (V. Lopez et al., 2017) which may be responsible for its calming properties. GABA is a neurotransmitter involved in signalling for the dampening of neurological activity, which may be the reason that s-limonene can help you to relax.
Terpenes are beneficial to mental health and even have benefits in harm reduction. You may have heard that a higher THC to CBD ratio is associated with less of the arguably negative, psychosis-like effects of THC (Hudson, R., Et al). We know a lot about terpenes and some other Cannabis compounds, like flavonoids and even cannabinoids in isolation, but what about their combined benefits?
This synergy between different cannabis compounds (terpenes, flavonoids, CBD isomers etc.) is called an entourage effect. It is believed that by mixing cannabis compounds from different plants, effects greater than those produced by individual compounds are generated.
What is the Entourage Effect?
The term made its debut in 1998 after two Israeli researchers, Mechoulam and Shabat, explained the effect for the first time. They suggested that compounds in cannabis which were previously considered inactive were actually increasing the activity of some key cannabis compounds found in cannabis plants.
Read CBD products marketing today, and you’ll find that many kinds of cannabis products purportedly operate according to the entourage effect. The entourage effect goes more-or-less like this:
“The action of Terpenes, CBD and THC compounds from different plants is synergistic, in that it produces an effect as a whole, which is greater than the individual compounds otherwise would do.”
(Ben-Shabat et al, 2020).
This has implications for a lot of cannabis products. For example, CBD oils used to alleviate pain may benefit from a certain terpene profile that is relaxation-specific.
There is some controversy, and not all studies agree that the effect has scientific validity (M. Santiago et al., 2019) (Russo, 2011) (S. Cogan, 2019). Such discrepancies between studies lead some of the scientific community to believe that the entourage effect is no more than clever marketing. The industry is not stringent regulated, it’s true, but the dismissal seems premature to us.
To begin with, the cannabis industry is young, and even now emerges covered in the ashes of ignorant derision. There is some human testing now, but they are few and far between, with foundational neuroscience systems studies still lagging behind the industry’s territorial advances. Until these studies happen, most of the claims we can make about the existence of an entourage effect between cannabis compounds will remain vague. The boldest claim we can make given what we know is that the terpene compounds involved at least work individually to produce the effects listed below (See: The Different Types of Terpenes).
We reached out to Ivan Esquerra, a PhD neuroscience student at UCL and founder of the London-based harm-reduction, non-profit start-up ‘Drugs and Me’ for further clarification.
‘It’s unfortunate that a lot of the studies that need to take place involve highly precise equipment, and require high experimenter knowledge, such as patch-clamp studies. There are hardly neuroscience systems studies, or sufficiently controlled human studies comparing the effects of different chemovars.’
It stands to reason that combinations of oils would generate combined effects that activate more pathways. Shabat and Mechoulam gave as evidence the efficacy of whole botanical extracts versus their isolated compounds, and we think it makes a lot of sense. In any case, it is important that more studies into the entourage effect between different cannabis compounds take place in order to put this question to rest.
Below: A closer look at the key compounds involved.
The Different Types of Terpenes:
Terpenes are rumoured to produce some of the subtler effects we experience between varieties of the plant (1 periodic edibles). Below are some of the main cannabis terpenes and their effects:
- Myrcene has a herbaceous scent, it is found in bay, mango and hops among others.
- It is thought to have antioxidant properties, and to treat insomnia, pain and inflammation (Hartsel et al., 2016).
- Found in citrus fruit peels, it takes its name from the French name for lemons, ‘Limon’.
- Abundant in cannabis, it has been identified as having antioxidant, anti-cancer, and anti-tumorigenic properties (Jessica A. Miller et al. 2014) (S C Chaudhary et al. 2012). In rat model studies, it has been shown to be an effective anxiolytic, which could help it to balance chemovars that are higher on the paranoia scale.
- · Anti-inflammatory effects in model organism studies, and anti-inflammatory effects and asthma (Bacanlı, M., Başaran, A.A. and Başaran, N. (2018).
- Found in the aromas of black pepper, rosemary, and hops it is the component responsible for the identification of cannabis by drug-sniffer dogs (E Stahl et al., 1973).
- Also found in cumin and lilacs, it’s part of what gives Jack Herer that roast dinner smell.
- Has a complex profile, with multiple notes. Some are herbaceous, flowery and others are citrusy, and others piney.
- Nearly all terpinolene dominant chemovars are THC-dominant
- Possible antifungal qualities, and insect repelling.
- Sedative (Pubchem, 2020)
α-Pinene & β-Pinene:
(Pinene has two ‘isomers’, or similar forms with slightly different effects)
- Dominant scent is pine in both isomers.
- Antibacterial (Ethan B Russo, 2011)
- α-Pinene Increases alertness (Ethan B Russo, 2011)
- Possible Anticancer effects, used in Chinese medicine (W. Chen et al., 2015)
- Bronchodilator and expectorant (A. C. Rohr et al., 2002)
- Anti-inflammatory (Russo, 2011)
- Responsible for the distinctive aroma of hops in beer
- Used in Chinese medicine
- Aids in weight loss by acting as an appetite suppressant (Hartsel et al., 2016).
- Woody and herbaceous, ocimene are used in perfumes for its sweet aroma. The word comes from the old Greek name for basil, Ocimum. Ocimene is anti-fungal (Russu & Marco, 2016)
- Also found in lavender, these are relaxing floral aromas that help with anxiety through their calming effect (López et al., 2017).
- Sleep inducing
Terpenes in CBD
Terpenes are a hot topic in the states at the moment. The 2018 farm bill that paved the way for hemp farming has ramped up CBD production on a great scale. Typically the CBD is harvested from whole hemp plants, although higher CBD varieties often use the flowers. These plants are then treated, usually with ethanol, which when heated volatilizes the terpenoids. These terpenoids are then re-added, usually using terpenes that come from other sources such as limonene from citrus peels.
Typically these are added to all kinds of CBD oils, from medical kinds to vaping oils. It’s important to know which terpenes your products contain, and to consider if you want to ingest terpenes in this way.
There is hardly any data presently available on the products of terpenoids that have been volatilized by heating, which could turn out to be a sleeping dragon for vape companies.
Below: Most popular terpenes used in CBD oil products.
Cannabis and hemp plants are packed full of compounds with more effects than modern medicine has been able to yet describe. A lot of attention is going into how terpenes can be harnessed to improve the effects of cannabis, for example in finding bespoke chemovars for distinct individuals.
Going forward we should expect to see more research into the entourage effects of different cannabis phytochemicals, and more terpene scales on cannabis products to reflect our growing understanding of these fascinating oils!
- Edibles, in (2014). Periodic edibles. [online] Periodic edibles. Available at: https://www.periodicedibles.com/faq-edible-terpene-effects [Accessed 17 May 2020].
- Drugsand.me. (2020). Why terpenes matter. [online] Available at: https://drugsand.me/en/blog/why-terpenes-matter/ [Accessed 17 May 2020].
- Ben-Shabat, S., Fride, E., Sheskin, T., Tamiri, T., Rhee, M.H., Vogel, Z., Bisogno, T., De Petrocellis, L., Di Marzo, V. and Mechoulam, R. (1998). An entourage effect: inactive endogenous fatty acid glycerol esters enhance 2-arachidonoyl-glycerol cannabinoid activity. European journal of pharmacology, [online] 353(1), pp.23–31. Available at: https://www.ncbi.nlm.nih.gov/pubmed/9721036 [Accessed 17 May 2020].
- Hudson, R., Renard, J., Norris, C., Rushlow, W.J. and Laviolette, S.R. (2019). Cannabidiol Counteracts the Psychotropic Side-Effects of Δ-9-Tetrahydrocannabinol in the Ventral Hippocampus through Bidirectional Control of ERK1–2 Phosphorylation. The Journal of Neuroscience, [online] 39(44), pp.8762–8777. Available at: https://www.jneurosci.org/content/39/44/8762 [Accessed 17 May 2020].
- ZHOU, W., YOSHIOKA, M. and YOKOGOSHI, H. (2009). Sub-Chronic Effects of s-Limonene on Brain Neurotransmitter Levels and Behavior of Rats. Journal of Nutritional Science and Vitaminology, [online] 55(4), pp.367–373. Available at: https://pubmed.ncbi.nlm.nih.gov/19763039/ [Accessed 18 May 2020].
- Expert Review of Clinical Pharmacology. Peter S. Cogan (2019). The ‘entourage effect’ or ‘hodge-podge hashish’: the questionable rebranding, marketing, and expectations of cannabis polypharmacy. [online] Available at: https://www.tandfonline.com/doi/abs/10.1080/17512433.2020.1721281?journalCode=ierj20 [Accessed 23 May 2020].
- Cannabis and Cannabinoid Research. (2017). The Clinical Significance of Endocannabinoids in Endometriosis Pain Management | Cannabis and Cannabinoid Research. [online] Available at: https://www.liebertpub.com/doi/10.1089/can.2016.0035 [Accessed 23 May 2020].
- Russo, E.B. (2011). Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects. British Journal of Pharmacology, [online] 163(7), pp.1344–1364. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165946/ [Accessed 23 May 2020].
- López, V., Nielsen, B., Solas, M., Ramírez, M.J. and Jäger, A.K. (2017). Exploring Pharmacological Mechanisms of Lavender (Lavandula angustifolia) Essential Oil on Central Nervous System Targets. Frontiers in Pharmacology, [online] 8. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5437114/#s4title [Accessed 1 Jun. 2020].
- PubChem (2020). Terpinolene. [online] @pubchem. Available at: https://pubchem.ncbi.nlm.nih.gov/compound/Terpinolene [Accessed 17 Aug. 2020].
- Sciencedirect.com. (2010). Limonene – an overview | ScienceDirect Topics. [online] Available at: https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/limonene [Accessed 24 May 2020].
- Stahl, E. and Kunde, R., 1973. Die Leitsubstanzen der Haschisch-Suchhunde. Kriminalistik: Z Gesamte Kriminal Wiss Prax, 27, pp.385-389. – sniffer doge
- Chen, W., Liu, Y., Li, M., Mao, J., Zhang, L., Huang, R., Jin, X. and Ye, L. (2015). Anti-tumor effect of α-pinene on human hepatoma cell lines through inducing G2/M cell cycle arrest. Journal of Pharmacological Sciences, [online] 127(3), pp.332–338. Available at: https://www.sciencedirect.com/science/article/pii/S1347861315000110 [Accessed 25 May 2020].
- Rohr, A.C., Wilkins, C.K., Clausen, P.A., Hammer, M., Nielsen, G.D., Wolkoff, P. and Spengler, J.D. (2002). UPPER AIRWAY AND PULMONARY EFFECTS OF OXIDATION PRODUCTS OF (+)- α -PINENE, d -LIMONENE, AND ISOPRENE IN BALB/ c MICE. Inhalation Toxicology, [online] 14(7), pp.663–684. Available at: https://pubmed.ncbi.nlm.nih.gov/12122569/ [Accessed 25 May 2020].
- Prashar, A., Locke, I.C. and Evans, C.S. (2004). Cytotoxicity of lavender oil and its major components to human skin cells. Cell Proliferation, [online] 37(3), pp.221–229. Available at: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2184.2004.00307.x [Accessed 28 May 2020].
- Expert Review of Clinical Pharmacology. (2019). The ‘entourage effect’ or ‘hodge-podge hashish’: the questionable rebranding, marketing, and expectations of cannabis polypharmacy. [online] Available at: https://www.tandfonline.com/doi/abs/10.1080/17512433.2020.1721281?journalCode=ierj20 [Accessed 1 Jun. 2020].
- Miller, J.A., Lang, J.E., Ley, M., Nagle, R., Hsu, C.-H., Thompson, P.A., Cordova, C., Waer, A. and Chow, H.-H.S. (2013). Human Breast Tissue Disposition and Bioactivity of Limonene in Women with Early-Stage Breast Cancer. Cancer Prevention Research, [online] 6(6), pp.577–584. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3692564/ [Accessed 1 Jun. 2020].
- Chaudhary, S., Siddiqui, M., Athar, M. and Alam, M.S. (2012). d-Limonene modulates inflammation, oxidative stress and Ras-ERK pathway to inhibit murine skin tumorigenesis. Human & Experimental Toxicology, [online] 31(8), pp.798–811. Available at: https://pubmed.ncbi.nlm.nih.gov/22318307/ [Accessed 1 Jun. 2020].
- Bacanlı, M., Başaran, A.A. and Başaran, N. (2018). Effects and Usage of a Citrus Compound, Limonene. Polyphenols: Prevention and Treatment of Human Disease, [online] pp.419–424. Available at: https://www.sciencedirect.com/science/article/pii/B9780128130087000321 [Accessed 1 Jun. 2020].
- Hartsel, J.A., Eades, J., Hickory, B. and Makriyannis, A. (2016). Cannabis sativa and Hemp. Nutraceuticals, [online] pp.735–754. Available at: https://www.sciencedirect.com/science/article/pii/B978012802147700053X [Accessed 17 Aug. 2020].
- Ethan B. Russo, Jahan Marcu, in Advances in Pharmacology, 2017Sciencedirect.com. (2017). Advances in Pharmacology | Cannabinoid Pharmacology | ScienceDirect.com by Elsevier. [online] Available at: https://www.sciencedirect.com/bookseries/advances-in-pharmacology/vol/80/suppl/C [Accessed 17 Aug. 2020].
Author: Andrés Felipe BSc. Plant Biology