At What Temperature Does THC Vaporize?

THC begins to evaporate into inhalable vapor at temperatures well below its true boiling point, which is why vaporizer devices typically operate somewhere between 170°C and 230°C (roughly 340–450°F). But the specific temperature you see quoted most often online, usually around 157°C (315°F), is wrong. That figure comes from measurements taken under laboratory vacuum and has been misrepresented for years as the temperature at which THC boils at normal atmospheric pressure. The real story is more interesting and has real consequences for anyone trying to dial in a vaporizer.

Why the “157°C” Number Is Wrong

If you search for THC’s boiling point, you will almost certainly find a number in the range of 155–157°C. That figure has been copied across cannabis websites, product manuals, and even some scientific reviews for years. The problem is that it was originally measured under high vacuum, at a pressure of about 0.05 torr, which is a tiny fraction of normal atmospheric pressure. Under vacuum, compounds boil at much lower temperatures than they do in everyday conditions. The 157°C number is technically accurate for that specific vacuum level but meaningless for someone vaping at sea level.

A 2023 analysis in Cannabis and Cannabinoid Research traced this confusion and found that dozens of documents and websites repeat the 155–157°C figure for THC and 160–180°C for CBD without noting that those values apply only under vacuum, not at normal room pressure.¹ The sources these websites draw from often do not even specify what pressure the measurement was taken at, making the number look like a universal constant when it is anything but.

What the Actual Boiling Point of THC Is

Measuring the true boiling point of THC at normal atmospheric pressure (760 torr, or 1 atmosphere) is surprisingly hard. At the temperatures required, THC starts to decompose before it can fully boil, so there is no clean way to observe a bubbling phase transition the way you can with water. Researchers have to estimate the normal boiling point using indirect methods, and two recent approaches have produced significantly different numbers.

A 2025 study using thermogravimetric analysis and differential scanning calorimetry placed THC’s normal boiling point at about 245°C (473°F), with a 95% confidence interval of ±6°C. The same study found that the commonly purported value of 157°C is far too low.² Meanwhile, the 2023 analysis mentioned earlier used the Clausius-Clapeyron equation to extrapolate from vapor pressure measurements at lower temperatures, arriving at boiling point estimates higher than 400°C. That paper noted its results aligned with several earlier researchers who also found the boiling point to be well above 300°C.¹

The gap between 245°C and 400°C+ is substantial, and it reflects genuinely different methodologies rather than a simple measurement error. Both groups agree on the important practical point: the boiling point is far higher than 157°C, and THC does not need to reach its boiling point to produce inhalable vapor. That second point is where the conversation shifts from chemistry trivia to something you can actually use.

Evaporation Is Not the Same as Boiling

The confusion around THC’s boiling point matters less than most people think, because vaporizers do not actually boil THC. They evaporate it. Evaporation can happen at any temperature below the boiling point, just more slowly. Think of a puddle drying on a warm sidewalk: the water is not at 100°C, but molecules are still escaping into the air. THC behaves the same way. At 155°C its vapor pressure is only about 0.05 torr, so it evaporates slowly. But raise the temperature and evaporation accelerates dramatically.¹

The rate increase is not linear. According to the Clausius-Clapeyron relationship, compared with vaping at 160°C, the evaporation rate of THC at 180°C is roughly 3 times greater, at 200°C about 8 times greater, and at 220°C nearly 20 times greater. Each 20°C increase roughly triples the rate.¹ This is why most practical vaporizers work in the 170–230°C range. Below about 170°C, the evaporation rate is too slow to produce satisfying vapor in a normal puff. Above about 230°C, you get fast evaporation but also start running into problems with degradation, which we will get to.

Decarboxylation Has to Happen First

Raw cannabis flower contains very little free THC. The psychoactive compound is stored mostly as THCA (tetrahydrocannabinolic acid), its inactive precursor. For THC to become pharmacologically active, THCA has to lose a carboxyl group in a heat-driven reaction called decarboxylation. This step is a prerequisite for getting high, and it happens at lower temperatures than full vaporization.

Decarboxylation begins at temperatures as low as 80°C and proceeds faster as the heat increases. Research studying the kinetics of this reaction across temperatures from 80°C to 160°C found that it follows first-order kinetics, with THCA converting faster than its counterparts CBDA and CBGA.³ A separate kinetic study of hemp plant material confirmed this rate ordering, showing THCA had the fastest decarboxylation rate among the cannabinoid acids tested.⁴

In a vaporizer operating above 170°C, decarboxylation happens almost instantly. The heat simultaneously converts THCA to THC and then evaporates that THC into the vapor stream. With dry herb vaporizers, the two processes overlap in real time. With concentrates that have already been decarboxylated during extraction, the conversion step is mostly done before the material enters the device, and the vaporizer’s job is purely evaporation.

The Practical Sweet Spot for Vaping

Given that THC evaporates meaningfully above about 170°C and degrades noticeably above about 230°C, the practical operating window for most vaporizers falls in that range. An early and influential study of the Volcano vaporizer systematically varied temperature settings, sample types, and balloon volumes to optimize THC delivery while preventing the formation of breakdown products like cannabinol (CBN) and delta-8-THC.⁵ The study demonstrated that careful temperature control could maximize the amount of THC reaching the user while keeping unwanted byproducts low.

Lower temperatures in the range, around 170–190°C, produce thinner, lighter vapor with a gentler flavor profile. Higher temperatures, around 200–230°C, produce denser clouds and faster cannabinoid delivery, but they also start to pull in more terpene degradation products and can push the vapor toward the harsh, smoky character that vaporizing is supposed to avoid. Medical users who have been interviewed about their vaping habits report noticing that vaporized cannabis seems to contain “some of the compounds but not all of the compounds” compared to smoking, suggesting the selective extraction that temperature control enables.⁶

One practical consequence of this window: if you are vaping at the low end and feeling like the effects are weak, raising the temperature by even 20°C can roughly triple the evaporation rate. That is a big jump from a small dial turn, and it explains why many people find the difference between 180°C and 200°C more dramatic than the numbers suggest.

What Happens When Temperatures Get Too High

Pushing a vaporizer past the 230–250°C range does not just give you more THC vapor. At elevated temperatures, THC itself begins to break down. One pathway converts THC into cannabinol (CBN), a mildly sedative compound. Research on cannabis resin found that the rate of THC-to-CBN conversion increases with temperature, and the reaction accelerates substantially as temperatures climb.⁷ So cranking up the heat does not just waste THC; it actively converts it into something less psychoactive.

The bigger health concern at high temperatures comes from terpenes, the aromatic compounds that give cannabis its smell and flavor. Terpenes are small, volatile molecules that evaporate readily, many of them at lower temperatures than THC. When exposed to extreme heat, terpenes do not just evaporate cleanly. They break apart through thermolysis, producing a range of harmful compounds including benzene, methacrolein, and methyl vinyl ketone.⁸ A follow-up study found that THC alone and THC mixed with terpenes both generated degradation products at high temperatures, but added terpenes led to higher levels of gas-phase toxicants and elevated levels of isoprene.⁹

This is relevant to dabbing in particular, where concentrate is applied to a heated surface that can easily exceed 400°C. At those temperatures, the benzene and alkyl benzenes that form during terpene breakdown become a genuine exposure concern.¹⁰ The takeaway is not that all vaping is dangerous, but that temperature is doing double duty: it determines how much THC you get and how many harmful byproducts come along with it. The two goals pull in opposite directions, which is why the 170–230°C range represents a genuine compromise rather than an arbitrary preference.

Your Device’s Temperature Display Might Be Lying

Knowing the ideal temperature range is only useful if your device actually delivers it. A study using thermal imaging to measure the real temperatures of vaporizer heating coils found alarming discrepancies, especially in voltage-controlled devices. The temperature-controlled system tested was relatively accurate: set to 420°C, it averaged 420 ± 9.5°C at the coil. But a variable-voltage system set to its lowest setting (2.4V), which a user might assume would produce gentle heat, averaged 443 ± 56.1°C at the coil. At the highest voltage (4.0V), that same system reached an average of 543°C with enormous variability of nearly ±96°C.¹¹

Only the temperature-controlled system consistently kept its coil below 400°C for the full duration of a puff. The voltage-based systems were unpredictable enough that even on a “low” setting, the coil could spike into the range where terpene degradation and THC breakdown become serious. If you are using a cheap cartridge-style vape pen with only a voltage dial or a single fixed voltage, the temperature at the coil during your puff could be hundreds of degrees higher than you assume.

This has practical implications. A user who thinks they are vaping gently at a low voltage setting may actually be exposing their material to temperatures that produce the same kinds of degradation products researchers see in dabbing studies. If temperature control matters to you, and the evidence suggests it should, investing in a device that actually regulates temperature rather than just voltage is one of the few hardware decisions that genuinely affects what you inhale.

How Vaporization Compares to Smoking

One of the main reasons people vaporize instead of smoke cannabis is the assumption that lower temperatures mean less exposure to combustion byproducts. That assumption holds up reasonably well in controlled studies. A pharmacokinetic comparison of smoked and vaporized cannabis found that blood concentrations of THC and its metabolites were dose-dependent for both methods but were consistently higher following vaporization compared to smoking at equivalent doses.¹² In other words, vaporizing delivers more THC per gram of material than combustion does.

That finding makes physical sense. Smoking burns cannabis at temperatures well above 600°C, which destroys a substantial fraction of the THC before it ever reaches your lungs. A vaporizer operating at 200°C evaporates THC efficiently without combusting the plant matter around it. You lose less to thermal destruction and inhale fewer combustion byproducts like carbon monoxide and tar. The trade-off is that smoking delivers a broader, less selective extraction: everything in the plant, including potentially beneficial compounds, gets released at once, along with everything harmful. Vaporization is more selective, which is a benefit if what you want is cannabinoids and a drawback if you believe the full spectrum of plant compounds matters for your experience.

Altitude, Atmosphere, and Other Variables

Because boiling point depends on atmospheric pressure, where you live subtly affects how quickly THC evaporates. At higher altitudes, atmospheric pressure drops, which lowers the effective boiling point of every liquid, including THC. Someone vaping in Denver (about 630 torr atmospheric pressure) gets slightly more aggressive evaporation at a given temperature setting than someone in a coastal city at sea level (about 760 torr). The difference is small in practical terms, but it is real and measurable, and it is rooted in the same physics that explains why the 157°C myth persists: that figure is accurate for a pressure of 0.05 torr, which is essentially a deep vacuum.¹

The form of the cannabis material also matters. Dry herb, live resin, distillate, and rosin all present THC to the heating element differently. In dry herb, THC is locked inside trichomes on plant matter. Heat has to penetrate the plant surface, break open those trichomes, and then evaporate the released cannabinoids. In a distillate cartridge, THC is already a purified liquid sitting directly on the coil. The distillate will begin producing vapor at a lower effective temperature setting because there is less material standing between the heat source and the THC molecules. Concentrate users sometimes find they prefer lower temperature settings than herb users for this reason, and the physics backs that up.

Terpene Temperatures and the Entourage Question

THC is not the only volatile compound in cannabis, and it is not the first to evaporate. Many terpenes, the compounds responsible for the plant’s smell and possibly some of its effects, have boiling points and vapor pressures that cause them to evaporate at lower temperatures than THC. Myrcene, limonene, and linalool all become volatile at relatively gentle heat. This is why a low-temperature puff often tastes more flavorful than a high-temperature one: you are selectively pulling terpenes before the heavier cannabinoids fully join the vapor.

Some medical cannabis advocates suggest that terpenes contribute meaningfully to therapeutic outcomes through what is sometimes called the entourage effect. Whether or not that mechanism holds up under rigorous scrutiny, the temperature-dependent volatility of terpenes gives users a real lever to adjust their experience. Starting a session at a lower temperature and gradually increasing it is a common technique among dry herb vaporizer users specifically because different compounds come off at different heats. The first draws tend to be flavorful and light, the later draws heavier and more cannabinoid-dense.

There is a flip side. At higher temperatures, the terpenes that evaporate cleanly at low heat start to decompose. The same compounds that give a low-temperature puff its pleasant aroma can break down into harmful byproducts if overheated. This reinforces the 170–230°C window as a range where you get meaningful terpene vapor without pushing those molecules into destructive thermolysis.

When THC Converts to CBN Over Time

Temperature is not the only factor that degrades THC. Time and storage conditions matter too. THC slowly converts to CBN even at room temperature, and the rate increases with heat exposure. In cannabis resin, researchers found that the transformation rate of THC into CBN increases with temperature, with a noticeable acceleration at elevated temperatures and acidic conditions.⁷ This is relevant to anyone storing cannabis or concentrates in warm environments: you are not just losing potency through evaporation, you are actively converting your THC into a different, less psychoactive compound.

CBN has historically been described as the “sleepy cannabinoid,” though the evidence for that characterization is thin. What is better established is that old, heat-exposed cannabis with high CBN content is less potent in terms of the classic THC experience. If your stored flower or cartridge has been sitting in a hot car or a warm drawer for weeks, some of the THC is now CBN regardless of what temperature you eventually vape it at. Cool, dark storage slows this conversion considerably.

1
PubMed Central. Vapor Pressure, Vaping, and Corrections to Misconceptions Related to Medical Cannabis’ Active Pharmaceutical Ingredients’ Physical Properties and Compositions
2
PubMed Central. Application of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) to estimate the normal boiling points of ∆9-tetrahydrocannabivarin (THCV) and ∆9-tetrahydrocannabinol (THC)
3
PubMed Central. Decarboxylation Study of Acidic Cannabinoids: A Novel Approach Using Ultra-High-Performance Supercritical Fluid Chromatography/Photodiode Array-Mass Spectrometry
4
Industrial & Engineering Chemistry Research. Cannabinoid Decarboxylation: A Comparative Kinetic Study
5
PubMed. Evaluation of a vaporizing device (Volcano) for the pulmonary administration of tetrahydrocannabinol
6
PubMed Central. A Qualitative Analysis of Cannabis Vaporization among Medical Users
7
PubMed Central. Kinetics of CBD, Δ9-THC Degradation and Cannabinol Formation in Cannabis Resin at Various Temperature and pH Conditions
8
PubMed Central. Toxicant Formation in Dabbing: The Terpene Story
9
PubMed Central. Aerosol Gas-Phase Components from Cannabis E-Cigarettes and Dabbing: Mechanistic Insight and Quantitative Risk Analysis
10
PubMed Central. Cannabis concentrate vaping chemistry
11
PubMed Central. Thermography of cannabis extract vaporization cartridge heating coils in temperature- and voltage-controlled systems during a simulated human puff
12
PubMed Central. Acute Pharmacokinetic Profile of Smoked and Vaporized Cannabis in Human Blood and Oral Fluid