What are terpenes? Terpenes are the signature scent of cannabis – like an aromatic fingerprint that contributes to each plant’s unique personality. Crack open a jar of cannabis flower and the first thing that greets you isn’t THC or CBD. It’s terpenes doing what they've evolved to do over millions of years: announce the plant’s presence to the world. There’s significantly more to it than that, though.
Understanding what terpenes are and how cannabis plants produce them opens a fascinating window into plant biology. These compounds aren’t accidental by-products. They’re part of an intricate biochemical system that allows cannabis to communicate, protect itself, and interact with its environment.
Lets try to answer the question “what are terpenes?” looking at how they form inside cannabis plants, why they exist in the first place, and the remarkable biological machinery responsible for producing them. After all, wouldn’t it be great to know how and why your buds smell and taste so bloomin’ fabulous?
What Are Terpenes?
At their core, terpenes are volatile organic compounds produced by plants, fungi, and even some insects. They belong to one of the largest and most diverse classes of natural molecules known as terpenoids. Built from repeating isoprene units, terpenes form the the aromatic backbone of countless natural scents found throughout the plant kingdom, influencing mint, fruits, and much more.
When asking "what are terpenes?" in relation to cannabis, they are primarily found in glandular trichomes - the tiny resin-producing structureS that coat cannabis flowers and nearby leaf surfaces. These trichomes house the chemical factories responsible for synthesising cannabinoids and terpene compounds simultaneously. If you've ever explored terpene descriptions on detailed strain profile pages, you may have noticed how closely aroma characteristics follow trichome development and resin density - a relationship that reflects the plant's biochemical priorities rather than marketing labels.
Terpenes are classified by size and molecular structure. In cannabis, the most common categories include:
Monoterpenes - Smaller, lighter molecules such as limonene and pinene.
Sesquiterpenes - Slightly larger molecules such as caryophyllene and humulene.
Diterpenes - Present in smaller quantities but still part of the plant's chemical diversity.
The sheer variety of terpene combinations explains why cannabis can express such a wide spectrum of aromas, from bright citrus and tropical fruit to deep earth, spice, and fuel.
What Are Terpenes: Why Plants Produce Terpenes
To fully answer the question "what are terpenes?", it helps to step back and look at their evolutionary purpose. Terpenes' didn't evolve to please human senses. They exist because they give plants survival advantages.
Research published in Frontiers in Plant Science describes terpenes as part of plants' chemical defence and communication systems, helping plants respond to environmental threats and biological interactions. Even a little light reading on the importance of terpenes will reveal the unreal sophistication behind these compounds.
Natural Defence Systems
Terpenes can act as chemical deterrents against herbivores, insects, and microbial pathogens. A comprehensive biochemical review indexed through PubMed highlights terpene roles in antimicrobial activity and ecological plant defence systems.
Environmental Stress Protection
Studies from the University of Mississippi's National Center for Natural Products Research - one of the longest running cannabis research programmes globally - suggest secondary metabolites such as terpenes may help protect plant tissue from environmental stress and oxidative damage.
Plant Communication
Plants can release terpene signals when injured by pests or environmental damage. These airborne compounds may alert neighbouring plants, prompting defensive chemical responses. Research examining plant volatile compounds demonstrates how terpene signals function as ecological warning systems.
Understanding these ecological roles provides essential context for understanding just what are terpenes within cannabis. They're not decorative traits. They're survival tools.
Where Terpenes Are Produced Inside Cannabis Plants
Cannabis plants produce terpenes primarily within specialised resin glands called trichomes. These are practically microscopic structures which form across the plant, but are most densely concentrated on female flowers.
For cannabis enthusiasts comparing resin-heavy cultivars, trichome density often correlates strongly with terpene complexity, which is why detailed genetic preservation work remains so important across professional breeding programmes.
The Three Main Types of Cannabis Trichomes
Cannabis trichomes are separated into three different types:
Bulbous Trichomes
The smallest and least complex structure, they produce limited resin and play a smaller role in terpene production.
Capitate-Sessile Trichomes
Slightly larger and more chemically active than bulbous trichomes. These contribute to resin production across leaves and flowers.
Capitate-Stalked Trichomes
The largest and most chemically productive trichomes. These structures contain the highest concentrations of cannabinoids and terpenes, and are responsible for most of the plant's aromatic output.
Inside these trichomes, specialised secretory cells use enzyme-driven biochemical pathways to convert basic plant metabolites into complex terpene molecules.
Further Reading:Everything You Need To Know About Cannabis Trichomes
What Are Terpenes Made From?
To answer what are terpenes at the molecular level, we need to examine how cannabis synthesises them from basic biochemical building blocks.
Cannabis plants rely on two major metabolic pathways to produce terpenes:
The Mevalonate Pathway (MVA Pathway)
This pathway occurs primarily in the cytoplasm of plant cells - the jelly-like substance found inside the cell that holds all the cell parts (organelles) in place. The Mevalonate Pathway generates precursor molecules that contribute to the formation of larger terpenes, particularly sesquiterpenes.
The Methylerythritol Phosphate Pathway (MEP Pathway)
Located inside plastids - tiny structures that make and store food or store pigments - the MEP pathway is reponsible for producing precursors used to synthesise monoterpenes and diterpenes. Both pathways generate molecules called isopentenyl diphosphate (IPP) and dimethlallyl disphosphate (DMAPP). These compounds act as universal terpene building blocks. Through enzyme activity, they combine in different arrangements to create hundreds of possible terpene structures.
A detailed biochemical overview published through the American Chemical Society explains how these terpene precursor pathways operate aromatic plant species, including cannabis.
The Role of Enzymes in Cannabis Terpene Production
Once terpene precursors form, enzyme families known as terpene synthases (TPS enzymes) shape them into final aromatic molecules. Each terpene synthase enzyme is responsible for catalysing specific molecular transformations. The genetic blueprint of a cannabis plant determines which terpene synthase enzymes it produces. This is one of the main reasons different cannabis cultivars display distinctive terpene profiles - something often observed when comparing terpene expressions across stable seed lines or preserved landrace genetics.
Understanding enzyme involvement adds another layer to the question of what are terpenes, showing how genetics directly shapes chemical diversity.
How Terpene Production Changes Throughout the Cannabis Life Cycle
Terpene production is not static. Rather, cannabis plants adjust terpene synthesis throughout their growth cycle.
Early Vegetative Growth
In early growth, terpene production is generally limited. The cannabis plant prioritises structural development and leaf expansion - packing on green muscle mass - rather than resin production.
Flower Initiation
As cannabis plants transition into flowering, trichome formation increases significantly. This is where major terpene synthesis kicks off.
Peak Flower Development
Terpene produciton typically ramps up during mid to late flowering stages when trichome density reaches its highest levels. The plant allocates subtantantial metabolic resources toward resin production during this period - a stage where many classic terpene-rich cultivars reveal their defining aromatic traits.
Late Flowering
Some terpene compounds begin to degrade or transform as flowers mature further. Environmental exposure and natural chemical changes will influence final terpene composition.
These dynamic shifts highlight how understanding what are terpenes requires viewing them as evolving chemical outputs rather than fixed plant traits.
Why Cannabis Produces Such Diverse Terpene Profiles
Cannabis is genetically diverse, and terpene variability is one of its most remarkable features. Several biological factors contribute to this diversity.
Genetic Variation
Different cannabis populations evolved across varied environments, climates, and geographic regions. Over time, natural selection favoured terpene combinations suited to specific environmental conditions, predators, and pollinators. This natural diversity continues to influence modern cannabis breeding and preservation work.
Evolutionary Adaptation
Terpene diversity allowed cannabis to thrive across climates ranging from Central Asian mountain regions to tropical environments. Each ecological niche encouraged unique terpene development patterns, which is why heritage and landrace varieties remain valuable for genetic research and breeding stability.
Chemical Synergy
Terpenes rarely appear in isolation. Instead, cannabis plants produce complex terpene mixtures that interact with one another. These layered chemical combinations contribute to the distinctive aromatic identity of each cultivar.
What Are Terpenes in Relation to Cannabis Aroma?
Terpenes are responsible for much of the sensory diversity associated with cannabis. It's been a common misconception that they're solely responsible for aroma and flavour - but it's not just terpenes - there are other factors contributing to the unique smell and taste of your favourite strains. But terpenes do play a huge part in shaping how each cultivar is recognised, described, and classified.
Some commonly studied cannabis terpenes include:
Myrcene
Often associated with earthy, herbal, or musky aromatic notes. Myrcene is common across many cannabis chemotypes, including OG Kush, White Widow, and Blue Dream.
Further Reading: Cannabis Terpenes Explained: Myrcene
Limonene
Responsible for bright citrus characteristics, Limonene is widely present in aromatic plant species beyond cannabis, but you'll find it in Super Lemon Haze, Gelato 41 BX, and Sour Diesel.
Further Reading: Cannabis Terpenes Explained: Limonene
Pinene
Producing sharp, forest-like aromas, Pinene is widely found in conifer plant species as well as cannabis strains like Jack Herer, Durban Poison, and Trainwreck.
Further Reading: Cannabis Terpenes Explained: Pinene
Caryophyllene
Recognised for its spicy, pepper-like aroma and notable for interacting with CB2 receptors in laboratory models. Caryophyllene is found in strains like Girl Scout Cookies, Sour Diesel, and Bubba Kush.
Terpinolene
Usually present in smaller quantities, terpinolene adds a lightly sweet, herbal and floral layer, making for a bright and fresh quality. Found in strains like Jack Herer, Super Lemon Haze and Strawberry Cough.
Together these, and many other compounds, demonstrate why understanding terpenes is essential for comprehending cannabis phenotype expression - something reflected across well-documented cultivar family lines and terpene-focused strain classification systems.
External Factors Influencing Natural Terpene Production
Although terpene production is genetically guided, cannabis plants naturally adjust terpene output based on on environmental interactions. Scientific literature examining plant secondary metabolites confirms that environmental cues influence terpene synthesis across many plant species.
Exposure to ultraviolet radiation, temperature fluctuations, and biological stressors may trigger changes in terpene production as part of plant defence and adaptation systems. Research investigating UV exposure and cannabinoid biosynthesis in cannabis suggest links between environmental radiation and secondary metabolite development. These responses reinforce the idea that terpene production is an adaptive biological function rather than a passive chemical process.
Why Cannabis Terpene Research is Still Evolving
Despite the growing interest, scientific understanding of cannabis terpene production is still evolving. Historically, legal restrictions limited research opportunities. As research are gaining better access to plant material, lab analysis, and genimic mapping tools.
Advances in metabolomics and genetic sequencing are helping scientists understand how terpene pathways interact with cannabinoid biosynthesis. This exoanding body of research continues to refine our understanding of exactly what are terpenes and how cannabis produces them - insights that help guide breeding projects and preservation initiatives focused on maintaining authentic terpene diversity.
What Are Terpenes as the Language of Cannabis?
So, what are terpenes? Terpenes are more than secret molecules. They are the chemical language cannabis uses to interact with its surroundings. From deterring predators to adapting to environmental pressures, terpene production reflects millions of years of evolutionary refinement.
Answering the intial question "what are terpenes and how do cannabis plants produce them?" reveals the extraordinary biochemical complexity behind every cannabis flower. These complex compounds mean aroma and flavour to the casual observer, but they form at the intersection of genetics, enzymatic activity, and ecological adaptation. They're dynamic, responsive, and endlessly varied.
As scientific exploration continues, terpene research will likely reshape how cannabis is classified, studied, and appreciated. For now, one thing remains clear: terpene production is one of cannabis' most fascinating achievements - one that continues to reward closer inspection, deeper preservation, and careful genetic stewardship.
