Terpenes in Medicinal Cannabis: Why They Matter (and Why Your Vaporiser Temperature Matters Too)

Most people assume THC is what makes one cannabis strain different from another. But if THC were the only active ingredient, every strain would feel the same. Cannabis contains hundreds of other compounds, especially terpenes, and their varying concentrations are thought to be part of why one product feels uplifting and another makes you sleepy. This proposed interaction is often called the entourage effect.

In other words: it's not just what you vape - it's how you vape it. And temperature is a big part of that.

What are terpenes?

Terpenes are the aromatic compounds in cannabis that give it its smell - citrus, pine, earthy, floral, spicy. They're also found in everyday plants like lavender, basil and lemongrass. In cannabis, terpenes are thought to work alongside THC and CBD to influence the overall effect.

Each terpene is released at its own rate, so different temperatures give you different compounds in different proportions. That is why changing your vaporiser temperature changes the effect of the same product.

Boiling point is not the temperature to set

You will see charts pairing each terpene with a boiling point and telling you to dial that number in. That advice is wrong, and it is worth understanding why before you read the list below.

A boiling point is the temperature at which a liquid turns to gas *throughout*, at normal air pressure. It is not the temperature at which a compound starts leaving your flower. Compounds are released long before they boil, which is exactly what your vaporiser relies on. You are not trying to boil anything.

The clearest example is caryophyllene. Its real boiling point is around 263°C, a temperature at which your flower would be burning, not vaporising. Yet at a normal 180°C setting it is released roughly 380 times faster than THC is. It reaches you perfectly well without ever coming near its boiling point.

So read the figures below as an order, most easily released first, rather than as settings to select:

• Pinene (boils ~155°C) - pine, fresh. Reported effects: alertness, memory retention, anti-inflammatory
• Myrcene (~168°C) - earthy, musky. Reported effects: sedative, analgesic, muscle relaxant
• Limonene (~176°C) - citrus, lemon. Reported effects: mood elevation, stress relief, anti-nausea
• Terpinolene (~185°C) - herbal, piney. Reported effects: sedative at higher doses, uplifting at low doses
• Linalool (~198°C) - floral, lavender. Reported effects: sedation, relaxation, anti-anxiety, sleep quality
• Caryophyllene (~263°C) - peppery, spicy. Reported effects: anti-inflammatory, analgesic, anxiolytic
• Humulene (~276°C) - earthy, woody. Reported effects: anti-inflammatory, appetite suppressant

Two of those numbers are higher than you will see almost anywhere else, and the common versions are simply wrong. Caryophyllene is widely published as 119°C or 130°C and humulene as 198°C. Those are measurements taken under vacuum, which lowers a boiling point substantially, then reprinted without the pressure they were measured at. At the air pressure you actually vape in, they are 263°C and 276°C.

The reported effects come from early and largely preliminary research, and the therapeutic role of individual terpenes is not well established. They are most useful as words for describing what does and does not suit you at your next appointment.

Why does vaporiser temperature matter?

When you use a dry herb vaporiser, the temperature setting shifts the proportions of terpene and cannabinoid you inhale. It does not pick particular ones out.

The 157°C often quoted for THC is another vacuum figure. THC's real boiling point is about 425°C, well past the point where cannabis combusts, and it still vaporises perfectly well at 180°C for the same reason the terpenes do.

What actually changes with temperature is the *mix*. The quickest-releasing compounds come through readily at any normal setting; the slower ones need more heat before you get much of them, and THC needs the most of all. Run low and the vapour is proportionally more terpene and less THC. Run high and you collect more cannabinoid, in warmer vapour, having already had most of the aromatic character in the first inhalations.

Understanding this gives you more control over the effect of the same product.

One thing worth knowing before you rely on exact numbers: the temperature on the display is the temperature of the oven or the heating element, not of your flower. How close the two are depends on whether your device heats by contact or by moving hot air, which is why the same setting can behave quite differently on two devices. Our guide to convection and conduction vaporisers covers what that means in practice, including why inhaling too quickly on an air-heated device gives you thin vapour at a setting that should be producing plenty. If you are still choosing a device, our guide to choosing a dry herb vaporiser covers the four approved ones and what they cost.

Lower settings (170°C to 185°C)

• Full release of most of your terpenes: pinene, myrcene, limonene, terpinolene and linalool
• Proportionally less of the two slowest to release, caryophyllene and humulene
• Low release of THC
• More flavour, milder effect

Higher settings (195°C to 210°C)

• Those same terpenes, still fully released
• More of the two slowest to release, caryophyllene and humulene
• Higher release of THC
• A stronger effect, and less aroma, because the quickest terpenes were released earlier

Where most patients settle

Most patients settle between 180°C and 205°C. Above 220°C the terpenes and cannabinoids start to degrade, and there is nothing to gain.

Temperature is part of your dose, so treat it as you treat the rest of the dose: begin at the lower end and raise it only if your symptoms are not adequately controlled. A higher setting delivers more THC per inhalation, which matters while you are finding your dose and is worth leaving alone once you have found it.

Example: targeting sleepier effects

Say you have a myrcene-dominant product. Myrcene is released readily at any normal setting, so there is no number you have to reach to get it. What changes as you raise the temperature is how much of the slower-releasing material arrives alongside it, THC included.

The claim that some terpenes need a higher temperature

You will read, almost everywhere, that the higher-boiling terpenes such as linalool only come through above about 199°C. The measurements do not support it. At an ordinary 180°C setting linalool is already being released around 2,200 times faster than THC, and caryophyllene around 380 times faster, despite boiling at 263°C. The published finding is that the terpenes are largely gone *before* much of the THC has been released at all.

At 180°C you are not leaving your linalool behind. You are leaving your THC behind: only 10 to 20 per cent of it has moved after 40 seconds.

So what does turning it up actually do?

It helps the slower-releasing compounds more than the quick ones. Anything hard to release gains a great deal from extra heat; the quick terpenes were already being released freely and have little room to speed up. So a hotter setting collects more THC. It feels stronger for that reason, not because a terpene has been unlocked.

What this means in practice

You cannot target a single terpene with the dial. Which terpenes are available to you is decided by the product you have been prescribed, not by your device.

What you can control is the balance and the order. Your first inhalations are terpene-rich and comparatively light on THC whatever setting you use. Stop early and that is most of what you have had. Carry on, or turn it up, and the balance moves towards the cannabinoids.

So the terpene profile comes from the product, which your doctor chooses on its full analysis rather than its name or its THC number. Temperature sets how strong the vapour is, and it is part of your dose.

That is the honest version of the common advice. Some products only feel properly sedating at a higher setting, but not because a switch flips at some terpene's boiling point. It is because you are collecting more THC. If a lower setting is not controlling your symptoms, raise it in small steps and give each one a few days.

Can I use this with oils or just flower?

This temperature guide is most relevant for dry herb vaporisers. Oils and capsules aren't affected by vaporiser temp. However, the terpene profile of an oil product may still be part of why one formula feels more "uplifting" and another more "sedating".

For those using concentrated or extract-based products, it's also worth understanding the full spectrum of cannabinoids at play.

Summary

• THC alone doesn't tell the full story.
• Terpenes are thought to contribute to how a product feels, although the evidence is still early.
• Vaporiser temperature sets how much THC you collect and how strong the vapour is. It cannot choose a terpene for you: which terpenes you have was decided by the product you were prescribed.
• Start at the lower end and raise the temperature only if your symptoms are not adequately controlled. Once you have found the setting that works, leave it alone.