A Plain Guide to Cannabis Terpenes

Cannabis terpenes are the aromatic compounds that give the plant its smell and taste. They are the reason one strain smells of pine and another of citrus or diesel, and they are not special to cannabis: the same compounds are in lemons, lavender, black pepper and pine trees. What is claimed for them goes much further than smell. This is a guide to the common ones, what they are supposed to do, and how much of that has been checked.

What terpenes are

Plants make terpenes partly for defence and signalling, including deterring pests. They evaporate easily, which is why you can smell them. Cannabis makes well over a hundred, in the same sticky glands that make THC and CBD. The mix varies from plant to plant, and it is the mix rather than any single terpene that gives a strain its character. When a product lists a “terpene profile”, this is what it means.

Terpenes are present in far smaller amounts than cannabinoids, usually a few per cent of the plant at most and far less in a CBD oil. That matters for everything below: the doses used in laboratory studies are often much higher than anything you would get from a product.

The common ones

Myrcene is one of the most common terpenes in cannabis, and often the most abundant. It smells earthy and musky, a little like cloves, and is also in mango, hops and lemongrass. It gets the reputation for the sleepy, heavy feeling people associate with “indica” strains. In animals it has shown pain-relieving and sedative effects at high doses. In people, that connection has not been tested — our article on myrcene and pain goes through what exists.

Limonene smells of citrus, because it is what makes citrus peel smell of citrus. It is the terpene people link with a brighter, more uplifting effect, and it is the one with the best evidence in people. In a 2024 study at Johns Hopkins, 20 healthy adults inhaled THC with or without limonene in a double-blind trial. Adding limonene reduced the anxiety and paranoia THC caused, more so at higher limonene doses, and did not blunt THC’s other effects. On its own, limonene did nothing noticeable. That is a real result, but note what it shows: limonene softened a side effect of THC. It did not show that limonene lifts mood by itself, and it says nothing about limonene in a CBD product.

Pinene smells of pine and rosemary. It is credited with alertness and with countering the memory fog of THC. In a 2025 controlled study of 19 adults, alpha-pinene did neither: even at relatively high doses, it did not reduce THC-related memory problems or noticeably change THC’s effects.

Linalool is the smell of lavender, and it carries lavender’s reputation for calm. There is decent human evidence that a lavender oil preparation reduces anxiety when taken as a capsule, and linalool is its main component. But that is lavender oil at pharmaceutical doses, not the trace of linalool in a cannabis product.

Caryophyllene is spicy and peppery, and is in black pepper and cloves. It is the odd one out: in laboratory studies it attaches to one of the body’s own cannabinoid receptors, which none of the others do. That has made it the poster terpene for anti-inflammatory claims. The work is in cells and mice.

Humulene is woody and hoppy, a contributor to the hoppy aroma of beer, and is often paired with caryophyllene. Terpinolene is floral and piney, and turns up in the strains people describe as energetic. For both, the claimed effects rest on very little.

Do they change the effect?

This is the big claim: that terpenes work together with cannabinoids so that a whole-plant product does more than its THC or CBD alone, the “entourage effect”. It is a reasonable idea, and smell affects mood on its own. But the direct human evidence consists of two very small trials with mixed results: limonene reduced THC-induced anxiety in 20 adults, while alpha-pinene did not reduce THC-related memory impairment in 19. That supports the possibility of specific interactions, not a general rule that terpene-rich cannabis or CBD works better. Beyond that, the evidence is laboratory work, and some careful studies have found that common terpenes do not act on cannabinoid receptors at all. The entourage effect is a hypothesis with mixed early support, not a demonstrated fact, and we say the same in our guide to full spectrum, broad spectrum and isolate.

The “indica makes you sleepy, sativa makes you alert” idea is a related claim, usually explained by terpenes. People do report different effects from different products, but the labels are chemically unreliable: the same name can have quite different terpene profiles from different growers, and “indica” or “sativa” on a package does not reliably predict what a product will do.

What this means when you buy

Terpenes do not produce a THC-like high on their own. Concentrated terpene oils can irritate the skin and airways, though, and “natural” does not mean safe to inhale undiluted. Never add essential oils or DIY terpene blends to a vape.

If you like the smell and taste of a product, terpenes are why, and that is a fine reason to choose it. If a product promises a specific effect from its terpene profile, treat it as marketing. Most CBD products contain very little terpene content, and most certificates of analysis do not test for it, so “rich in terpenes” is usually an unverifiable claim. And some added “terpene blends” are made from other plants or synthesised, which is not a problem in itself but is not what “whole plant” suggests.

For a much deeper look at individual terpenes, our sister publication has a full terpene education section.

Nothing in this article is medical advice.