What Are Terpenes? A Plain Guide to Aromas, Types and Uses

What are terpenes?

Terpenes are a large family of compounds made by plants, many of which contribute to their smell. They occur in cannabis and hemp, as well as familiar herbs, flowers and fruit.

Peel a lemon and you release a sharp citrus scent, partly from limonene. Lavender's floral smell includes linalool, while pinene contributes to the fresh scent of pine. You already encounter these compounds without needing to know their names.

In cannabis products, the word “terpenes” usually refers to the aromatic ingredients that contribute to a flavour profile. It also covers closely related compounds called terpenoids, including linalool. You don't need the chemistry terminology to compare aromas, but it explains why ingredient lists sometimes use both words.

Terpene chart

This chart introduces six terpenes commonly discussed in cannabis. The strain column gives examples with published terpene profiles, rather than a guarantee that every batch will be high in that compound.

The examples draw on breeder-published analyses, including Dutch Passion's USA Special terpene profiles and myrcene profiles. These describe particular samples and genetics. They aren't independent proof of what another supplier's product contains.

A batch-specific certificate of analysis, often shortened to COA, is more useful than a strain name when you want to know which terpenes are present. Our guide to reading a COA explains how to interpret a lab report. Check how it expresses its results: a percentage of the total terpene mixture is different from a percentage of the whole product.

How to read an aroma profile

Use the chart as a starting point for recognising smells. Limonene suggests a citrus note, while caryophyllene suggests spice. A blend containing both can smell different from either ingredient on its own.

The proportions matter, too. Listing a terpene tells you it is present. It doesn't tell you how strongly you will notice it. Other aromatic compounds can also contribute to the finished scent.

Pinene has two common forms, alpha-pinene and beta-pinene. Lab reports often list them separately. In cannabis discussions, “caryophyllene” usually means beta-caryophyllene.

Terpenes in cannabis

Cannabis produces terpenes in the resin glands known as trichomes. Different plants produce different mixtures, which contribute to the range of citrus, herbal and spicy aromas associated with cannabis.

A plant's genetics help shape its terpene profile, but growing conditions and harvest timing also matter. Drying and storage can change the compounds retained in the finished flower. Research has measured differences between cannabis varieties and across their development, so a familiar strain name should be treated as a guide rather than a fixed recipe. See the study on gene networks and terpene accumulation and the study on drying and hemp aroma.

Terpenes don't explain every cannabis smell. Researchers have identified volatile sulphur compounds behind characteristic skunky notes, and other minor compounds contribute to unusual sweet or savoury aromas. That's one reason two products with similar terpene results can still smell different. Read the research on cannabis sulphur compounds and other aroma compounds.

Terpenes are also separate from cannabinoids such as THC, CBD and THCA. A terpene report describes aromatic composition. It doesn't establish cannabinoid potency. Our THCA Terpenes article introduces terpenes in the context of THCA products. For interpreting effects, keep the research limits below in mind.

Where terpenes come from: CDT, HDT and botanical

You'll often see three source labels on terpene products:

• CDT means cannabis-derived terpenes. These are extracted from cannabis plants.
• HDT means hemp-derived terpenes. These are extracted from hemp, which is a form of cannabis. Suppliers often use HDT as a more specific source label.
• BDT means botanically derived terpenes. In this market, it usually refers to terpenes sourced from plants other than cannabis, then combined into a blend.

These labels describe origin. They don't establish the purity, cannabinoid content or suitability of the finished product for a particular use.

A botanical blend can be formulated to resemble a cannabis aroma. A cannabis-derived extract can retain a mixture from the source plant, although extraction affects what is collected. Neither label guarantees that a product reproduces every part of a flower's scent.

You can compare the source descriptions on our cannabis-derived terpene page and botanically derived terpene page.

How terpenes are used

Terpenes and related aromatic compounds are used in fragrance and flavour formulations. In cannabis vape oils, they are commonly added to give an oil a particular flavour or restore aroma lost during processing.

A strain-inspired blend combines ingredients to create a recognisable profile. That name describes the intended aroma. It doesn't mean the bottle contains the same composition as every flower sold under that strain name.

Terpenes in vape oil

When comparing terpene vape products, look beyond the flavour name. Check the full ingredients, the intended use and any available batch testing. “Natural” and “food grade” do not establish that an ingredient is safe to inhale after heating.

Laboratory studies have found that heated terpenes can form additional compounds, including potentially harmful degradation products. What is emitted depends on the formulation and heating conditions. A terpene concentration or temperature setting alone cannot guarantee safety. See the studies on heated terpenoid emissions and pinene and terpinolene at vaping temperatures.

Terpenes in DIY blends

Concentrated terpene products are ingredients for formulation. They should not be vaped undiluted. Essential oils intended for fragrance or aromatherapy should not be substituted for ingredients specified for a vape formulation.

For any DIY project, confirm the intended use with the supplier and follow product-specific formulation guidance. There is no universal mixing ratio that makes every terpene blend suitable for every base oil or device. Testing a finished formulation involves more than checking how it tastes.

For base oil product information, see Owls Original Blend. Confirm product-specific formulation guidance before choosing a terpene blend.

Do terpenes have effects?

Researchers are studying how individual terpenes act in the body and whether they change responses to cannabinoids. Much of the evidence comes from laboratory or animal studies. Those findings do not automatically translate into benefits from a retail terpene product.

Human research is emerging. A small controlled study published in 2024 found that one tested combination of vaporised limonene and THC reduced some ratings of THC-related anxiety compared with THC alone. Limonene on its own did not produce effects different from placebo on the measures studied. The result concerns a specific experiment, and it doesn't establish that a citrus-flavoured vape treats anxiety. See the human limonene and THC study.

You may also encounter the term “entourage effect”. It describes the idea that cannabis compounds can influence one another's effects. Evidence depends on the compounds and conditions being tested. For example, a cell-based receptor study found that several common terpenes did not alter THC activity at the receptors examined.

If you're looking for a list of terpenes and effects, treat charts promising sleep, focus or pain relief with caution. An aroma description is useful for comparing flavour. It is not a reliable prediction of how a product will make you feel.

The practical reason to compare terpene profiles is to understand their contribution to aroma and flavour. This guide makes no therapeutic claims for terpene products.

Are terpenes legal in Ireland?

Terpenes are aroma compounds, chemically distinct from THC and other cannabinoids. Their presence in a product does not, by itself, establish that the product is legal to sell, import or use in Ireland.

Ireland controls cannabis and certain cannabis-related substances under its Misuse of Drugs legislation. A product described as “terpenes”, “hemp-derived” or “cannabis-derived” still needs to be assessed on its actual composition and applicable rules. See the Department of Health's cannabis guidance and the Misuse of Drugs Regulations 2017.

The source label alone is not a legal clearance. Before buying or importing a product, check its ingredients and obtain advice on the rules that apply to that specific product.

Explore strain aroma profiles

Our Zkittlez strain guide explains its reported aroma, popular crosses and the difference between a cannabis strain and a terpene blend.

For citrus and fruit aromas in the Gelato family, read our Lemon Cherry Gelato (LCG) strain guide, including its reported terpene profile and comparison with Runtz.

To compare the named profiles across both ranges, use our strain terpene chart. It groups all Owls Oil profiles for browsing and links to the exact available sizes.

For a tropical strain example, read our Pineapple Express strain guide, which explains its reference terpenes, taste and smell and links to both terpene ranges.

Compare lemon and pine strain references in our Haze terpenes guide, covering Super Silver Haze and Amnesia alongside four other catalogue profiles.

FAQs

What are terpenes in simple terms?

Terpenes are compounds made by plants, many of which contribute to smell. Familiar examples include limonene in citrus peel and pinene in pine. In cannabis products, terpene blends contribute to aroma and flavour.

Do terpenes get you high?

The common aroma terpenes in this guide do not cause the characteristic THC high on their own. A product containing terpenes can still be intoxicating if it also contains THC or another intoxicating ingredient. Check the full formulation.

Are terpenes safe to vape?

Terpenes cannot be assumed safe to vape because they come from plants or are used in food. Heating can create potentially harmful compounds, and inhalation safety depends on the finished formulation and conditions of use. Do not vape concentrated terpenes undiluted. A food-grade label or ingredient test does not prove the safety of a finished vape's emissions.

Are terpenes legal in Ireland?

Terpenes are chemically distinct from THC, but that does not establish the legal status of a finished product. Its composition and the rules covering its source, sale, import and intended use need to be checked. Cannabis-derived and hemp-derived labels do not provide legal clearance.

Explore terpene aromas

Compare the profiles in the Owls Oil terpene collection. Start with the aromas you prefer, then check each product's ingredients and intended use, along with its source.