Anyone who has ever smelled fresh flowers knows the effect: no two varieties smell alike. Sometimes citrusy, sometimes earthy, sometimes resinous like a pine forest. This is due to terpenes – volatile aroma molecules that are much more than just a scent.
It gets interesting where our work begins: Terpenes are extremely sensitive to heat. Only a fraction of what is in the flower makes it into consumption. How large this fraction is depends heavily on how you consume – and that's precisely where a closer look is worthwhile.
What Terpenes Actually Are
Terpenes are secondary plant compounds, chemically volatile hydrocarbons. They are found in almost all plants: in citrus peels, lavender, hops, rosemary, pine needles. In the plant, they fulfill tangible tasks – they deter predators, sometimes inhibit bacteria, and attract pollinators.
In cannabis, they are produced in the trichomes, the resinous glands on flowers and leaves. This is the same place where cannabinoids are formed – i.e., THC and CBD. Aroma and active ingredients literally sit next to each other.
Over 200 different terpenes have been detected in cannabis. However, only a handful are usually defining per strain.
Overview of the Most Important Terpenes
- Myrcene – earthy, musky, slightly clove-like. The most common terpene in many strains. Also found in hops and mango.
- Limonene – citrusy, fresh. The namesake for countless strains with "Lemon" in their name.
- Pinene – resinous, like pine and rosemary. Occurs in alpha and beta forms.
- Caryophyllene – peppery, spicy, woody. Also in black pepper and cloves.
- Linalool – floral, lavender-like. Found in lavender, coriander, and basil.
- Humulene – hoppy, slightly bitter. The reason why some strains resemble beer.
- Terpinolene – fruity-floral, rarely dominant, but present in many profiles.
- Ocimene – sweet, herbaceous. A rather underestimated terpene, to which we have dedicated a separate article.
What you consciously won't find here: a table "Terpene X makes you tired, Terpene Y makes you awake." Such lists circulate everywhere, but they are much less substantiated than their prevalence suggests. More on that later.
The Entourage Effect – What is Proven and What Isn't
The entourage effect describes the idea that cannabinoids, terpenes, and other plant compounds influence each other and together produce a different effect than isolated individual substances.
Ethan Russo popularized this with his review "Taming THC" (British Journal of Pharmacology, 2011). Important for context: This is a review that formulates a hypothesis and compiles possible mechanisms – not a clinical study proving the effect. Russo himself formulates cautiously. In its dissemination through blogs and shop pages, the subjunctive has become an indicative over the years.
An example of this is the often-repeated claim that myrcene increases the permeability of the blood-brain barrier and thereby enhances the effect of THC. This statement cannot be traced back to reliable human data to this day. It sounds good, but it is not proven.
Another finding is much better substantiated: Beta-caryophyllene binds directly to the CB2 receptor of the endocannabinoid system. Gertsch and colleagues demonstrated this in 2008 in the Proceedings of the National Academy of Sciences. This makes caryophyllene the only known terpene with directly proven cannabinoid receptor activity.
The honest state of affairs: That terpenes are pharmacologically active is undisputed. That a specifically controllable effect results from this in smoke or vapor is a plausible assumption with thin data. Anyone who tells you otherwise is selling you something.