Vaporizer Setting vs. Herb Temperature: Why They Are Two Different Numbers
The number on the display describes the heating element or air, not the raw material lying in the chamber. We gather what is known about this difference and state clearly what has not been publicly measured.
| Data Sheet | Measurement Status |
|---|---|
| Terpenes with atmospheric measurement | 6 out of 11 |
| Terpenes only under reduced pressure | 1 out of 11 number not comparable to others |
| Terpenes without specified pressure | 4 out of 11 |
| Works in the evidence base | 2 |
- How many studies. 2 works from 2022 to 2023, all listed in the table below along with the model.
- What has not been demonstrated. No study has been published measuring how much terpene from heated herb actually reaches the lungs and blood in humans. It is known in what order the components evaporate and what portion decomposes along the way, but not in
- What you won’t find here. Dosage recommendations or strain indications. The selection is determined by the attending physician, and cannabis herb is a raw material dispensed only by prescription.
- How to read this. The results of studies on rodents or in cell cultures do not directly transfer to a patient consuming herb, and the column with the model indicates what the work was actually about.
What is the difference between the temperature set on the vaporizer and the temperature of the herb?
The setting describes the heating element or airflow, not the raw material lying in the chamber. The herb heats up from what touches it, transfers heat to the inhaled air, and heats unevenly, so its actual temperature is different from the number on the display. There is definitely a difference, but it has not been publicly measured.
Heat reaches the raw material in two ways: through contact with the heated surface of the chamber or through the air flowing through the bed. In the first case, the hottest part is the piece of herb that is in contact with the wall, while the center of the bed lags behind. In the second, the reading refers to the air entering the chamber, not to what it will encounter along the way. Neither of these two readings is a measurement of the material itself.
Inhaling changes the picture once again. The inhaled air enters cold, absorbs heat from the bed, and carries it away with the vapor, so during inhalation, the raw material cools down, and between inhalations, it regains heat. The stronger the flow, the greater this loss. Therefore, the temperature of the herb is not a single value maintained throughout the session, but a fluctuating curve with the breath of the person consuming it.
The raw material itself is also not homogeneous: smaller pieces heat up faster than larger ones, and the layer lying closer to the heat source loses volatile components earlier than the rest. The vaporizer setting does not equal the temperature of the herb and cannot be converted with a single correction. We have not found a publicly available measurement that indicates how much these two values diverge with medicinal herb; inserting our own number here would be fabrication, not rounding.
Does the number on the display describe the composition of the inhaled vapor?
No. The setting only indicates how strongly the device heats. What evaporates first and in what proportion is determined by the vapor pressure of the individual components at a given temperature, and some of them decompose along the way into other substances. The composition of the vapor is therefore a derivative of chemistry, not a reading.
The first of the two works on this page examined the documentation reaching patients and their caregivers.
| Study | Model and route of administration | What was demonstrated |
|---|---|---|
| Zhu J et al., 2022 Scientific Reports PMID:35773373 |
laboratory measurement using thermal desorption coupled with gas chromatography and mass spectrometry, five monoterpenes at temperatures typical for vaporization | Among the five studied monoterpenes, the proportion of the starting compound that survived heating unchanged ranged from 97 to 98 percent for the most resistant to just 11 to 28 percent for the most unstable. The most resistant was myrcene, the most unstable was terpinolene, and the difference between the extreme values is nearly ninefold. This is not a share in the profile, but the percentage of the substance that did not decompose, and the denominator here is the amount introduced into the measurement. The oxidation products had molecular weights of 134, 150, or 152, among which p-(1-propenyl)-toluene, beta-pinon, and fenchol were likely identified. The authors note that the toxicity of inhaling these products is unknown, while allergic and irritating reactions to oxidized monoterpene oils are well documented. |
| Eyal AM et al., 2023 Cannabis and Cannabinoid Research PMID:35442765 |
analysis of own and literature data, review work with measurements of composition at various stages of processing | The authors reviewed the documentation reaching patients and their caregivers and found incorrect data and confusion between the concepts of boiling, vaporization, and evaporation, including incorrectly stated boiling temperatures of cannabinoids. The rate of loss of individual components is determined by their relative vapor pressure at a given temperature, not the boiling point. Loss begins during drying and curing and intensifies during decarboxylation, with monoterpenes evaporating first. During vaporization, terpenes are inhaled before cannabinoids, and commercial cannabis products are poorer in terpenes, especially monoterpenes, than the plants from which they were derived. Terms like full spectrum are directly called misleading by the authors, as no product replicates the composition of the plant. |
The rate at which a given component decreases is determined by its vapor pressure compared to the vapor pressures of the others, while the boiling point does not resolve anything here. Loss begins during drying and curing and accelerates during decarboxylation; monoterpenes escape first, so during vaporization, they reach the lungs before cannabinoids. Finished cannabis products carry fewer terpenes than the plants from which they were made, and phrases like full spectrum are directly called misleading by the authors, as the composition of the plant is not replicated in any of them.
The second work focused on measurement.
The most durable of the five studied was myrcene, the most fragile was terpinolene. Oxidation left behind molecules with masses of 134, 150, and 152, among which beta-pinon, fenchol, and p-(1-propenyl)-toluene were likely identified. Whether inhaling such products harms anyone has not been checked; it has long been known, however, that oxidized monoterpene oils can cause allergies and irritation. Therefore, the reading from the display does not indicate either how hot the material is or what enters the vapor.
Does a terpene evaporate only at its boiling point?
No. Molecules leave the surface under any conditions, and raising the temperature only accelerates this loss, and very rapidly. Boiling begins only when the vapor presses as hard as the surrounding air; it is a threshold for changing the nature of the phenomenon, not a switch. The entire targeting of a single component is based on this misunderstanding.
Water in an open glass disappears at room temperature, even though it is far from boiling. The same goes for plant oils: some molecules leave the surface under any conditions, and the higher the temperature, the faster. Therefore, the raw material loses its most volatile components already during drying and storage, before anyone reaches for the device.
The conclusion is inconvenient for tables: since evaporation has no activation threshold, no setting releases a single component separately. The vapor is always a mixture, and its proportions change during the session, as the most volatile components escape first. The physics of evaporation itself is discussed in a separate text on evaporating terpenes from herb.
Boiling points collected in databases describe the behavior of pure substances in a flask, not the behavior of the same molecule trapped in plant tissue, alongside resin and water. These are two different situations, and only the first has a measured number.
Why are terpene temperature tables not comparable?
Because the numbers in them come from measurements made under different conditions, and the most important condition, which is pressure, is often omitted. We checked eleven terpenes from this project in the public PubChem database, and only for six is the boiling point listed along with the pressure at which it was measured. The rest breaks down into three separate states.
Atmospheric records are held by caryophyllene, limonene, linalool, myrcene, pinene, and terpinolene. Humulene has only a measurement under reduced pressure. Nerolidol and ocimene carry a number without specified pressure, so it cannot be compared with the previous ones. Bisabolol and farnesene do not have a boiling point in this database at all.
Humulene shows what happens when a number is taken out of context. The only record that the database holds for it is the range of 99-100 degrees, but it was taken at a pressure of three millimeters of mercury. There is practically no air there. The same number placed in the same row as readings under normal pressure ceases to be a rounding and becomes a falsehood, as each describes a different physical arrangement.
The table below breaks down eleven names into four states. Only positions from the first row can be compared; the others describe either a different measurement setup or lack of measurement. A comparison that does not distinguish this looks like a measurement result, but is a patchwork of records with different meanings. Why popular tables provide different numbers for the same molecule is discussed in a separate text on their comparability.
| Record State in PubChem Database | Which Names It Concerns | What This Means |
|---|---|---|
| Boiling point with atmospheric pressure | caryophyllene, limonene, linalool, myrcene, pinene, terpinolene | numbers comparable to each other |
| Measurement only under reduced pressure | humulene | record 99-100 degrees at 3 mm Hg, not comparable with the row above |
| Number without specified pressure | nerolidol, ocimene | unknown under what conditions it was obtained |
| No boiling point in the database | bisabolol, farnesene | there is nothing to enter into the table |
How long does the effect last after vaporization, and how long after ingestion?
This is determined by the route of administration, not the device setting or strain name. Inhalation provides the first sensations within a few minutes and closes the episode within a few hours, while ingestion shifts the onset by several dozen minutes and prolongs the entire experience by more than twice. The difference arises from how the substance enters the bloodstream.
The route of administration determines the course more than the strain itself. After vaporization, the substance passes from the lungs to the blood almost immediately, so the first sensations appear after a few minutes, intensity increases for another ten to thirty minutes, and the whole experience lasts two to four hours. After ingestion, the raw material first passes through the intestine and liver, so the first sensations are waited for from half an hour to two, and the episode lasts six, sometimes eight hours. Hence the most common mistake with oral administration: someone who thinks nothing is happening after thirty minutes and takes another dose will receive both doses at once. The above ranges describe the route of administration, not the strain; no pharmacokinetic studies for a single cultivar have been published.
The setting does not shorten or prolong this course. It only changes how much substance can pass into the vapor in one session, not how quickly the body absorbs it and how long it will take to eliminate it.
What side effects are reported with cannabis herb?
Reports are collected for a medicinal product from a specific batch, not for the device setting. Heating adds a separate issue: some of the oxidation products formed in the chamber have no described inhalation toxicity, so they do not appear in any symptom list. Known symptoms therefore concern herb as a group of raw materials, not the method of heating.
Reports of adverse effects are collected for a medicinal product with a batch number, not for the strain name, so the following concerns cannabis herb as a group of raw materials. The most common symptoms include dry mouth, red eyes, and increased heart rate. Less frequently reported are dizziness upon rapid standing, daytime drowsiness, and temporary worsening of short-term memory, as well as anxiety that increases with dosage. A separate issue is medications taken concurrently, especially sedatives and those affecting coagulation: their assessment requires knowledge of the entire list of preparations, not just the description of the plant. We do not provide the frequency of these symptoms numerically, as public compilations for cannabis herb in Poland do not separate them by individual products.
The vaporizer setting does not change this list, as it was created from reports on products for which no one recorded how the device was adjusted. If temperature had its own contribution here, today’s data collections would not show it either.
What has not been studied about vaporizing terpenes from herb?
What happens between the chamber and the blood has not been studied. Both works on this page describe the behavior of substances outside the body: one compiles data on composition at processing stages, the other measures distribution in apparatus. None has studied a human inhaling vapor. The evidence base for this axis has not a single study involving humans.
No study has been published measuring how much terpene from heated herb actually reaches the lungs and blood in humans. It is known in what order the components evaporate and what portion decomposes along the way, but it is not known how much of this reaches the body or whether it has any measured effect. It has also not been demonstrated that setting the vaporizer to the temperature listed in the table as the boiling point of a specific terpene leads to inhaling that particular terpene.
This gap has a specific consequence for reading tables. Even if someone measured how much cooler the herb is than the heating element, they would still not know what portion of the released substance reaches the lung alveoli, what settles along the way, or what is exhaled. Without this link, the number on the display does not connect to anything that can be measured in a patient.
What does this mean for the patient?
First of all, that the decision about the method of administration is made by the attending physician, and no table from the internet can replace them. The raw material is dispensed to the patient only by prescription, so this page reports the state of knowledge and does not indicate any value as good for anyone. Questions are resolved through conversation with a doctor or pharmacist.
From the above, one number cannot be derived for everyone. The same raw material in two different chambers will behave differently, and the same chamber will behave differently with a fast versus a slow inhalation. Comparisons circulating online overlook both of these factors, as they provide a single value for the name of the component and remain silent about the rest of the system.
So what remains useful? The awareness that the setting is a parameter of the device, not a description of what the patient inhales, and that no one has publicly measured the difference between them. The strains currently available in Polish pharmacies are collected in a list of currently available strains, while hemp herb sold over the counter has its own place in the store.
Cannabis herb is a pharmaceutical raw material dispensed by prescription in the Rpw category, and the method and timing of administration are determined by the attending physician. The material is informational in nature and does not replace medical advice or information contained in the documentation of the medicinal product.
Frequently Asked Questions
Is the vaporizer setting the temperature of the herb?
No. The setting describes the heating element or the air entering the chamber, and the herb absorbs heat with a delay, cools during inhalation, and heats unevenly. The difference between these two values exists but has not been publicly measured.
How much cooler is the herb than the setting?
It is unknown. We have not found a publicly available measurement of this difference for medicinal herb, and the numbers circulating in guides do not have a source or method provided. Providing a specific value here would be fabrication.
Does a terpene start to evaporate only after exceeding its boiling point?
No. Evaporation occurs at any temperature, and the boiling point is the moment when the vapor pressure equals the surrounding pressure. The rate of loss of individual components depends on their relative vapor pressure, not the boiling threshold.
Why do temperature comparisons provide divergent numbers?
Because they mix records of different statuses. In the PubChem database, six out of eleven terpenes in this project have a boiling point with the specified pressure, one only under reduced pressure, two without specified pressure, and two do not have it at all.
Does heating destroy some components of the herb?
Yes, to a very different extent. In laboratory measurement of five monoterpenes, the proportion of the substance that survived heating unchanged ranged from 97 to 98 percent for the most resistant and from 11 to 28 percent for the most unstable.
Who determines the method of taking the herb?
The attending physician. Cannabis herb is dispensed by prescription, and the informational page does not replace their decision. This text describes the state of evidence and does not indicate any value as good for everyone.
Editorial text by the editorial team of ubucha.pl. Status as of August 2026.
