What is a dry herb vaporizer?

It's a device that heats cannabis flower until its cannabinoids and aromatic compounds turn to vapor, without burning the plant. It's different from an oil vape, which heats a cartridge of cannabis extract.

How do you use a dry herb vaporizer?

Grind the flower, load it into the chamber, set the temperature and wait for the device to heat up, then draw vapor through the mouthpiece. If you're new to it or switching from smoking, start with less than you're used to.

What's the difference between conduction and convection vaporizers?

Conduction heats flower by direct contact with a hot chamber wall, which is fast but can be uneven. Convection passes hot air through the flower, which heats more evenly but usually takes longer to warm up. Many devices combine both.

What temperature do dry herb vaporizers use?

Studies have used roughly 180°C to 226°C (356°F to 439°F). A 2016 lab study set every electric vaporizer to 210°C (410°F). Device thermostats vary, so the same number may not mean the same heat on every model.

Does a vaporizer burn the flower?

A temperature-controlled electric vaporizer shouldn't. In a 2016 lab study, only a flame-heated device with no temperature control showed signs of combustion such as ash and visible smoke.

Is vaping flower stronger than smoking it?

In a 2018 Johns Hopkins study of people who rarely use cannabis, the same dose produced stronger effects and higher blood THC when vaporized than when smoked. The researchers cautioned infrequent users to be careful with how much they use.

Is vaporizing safer than smoking?

The research doesn't settle that. A 2007 study found vaporizing caused little or no rise in exhaled carbon monoxide, a marker of combustion, compared with smoking. But the studies were small and short, and none followed people over the long term.

Can I use a vaporizer in public in California?

Generally no. California's ban on smoking cannabis in public places counts vaporizers as smoking.

A compact matte-black portable vaporizer beside a small glass dish of ground cannabis flower on a light wooden table

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Dry Herb Vaporizers Explained: How They Work and What Studies Found

By Pedro Garcia·October 18, 2026·5 min read

A dry herb vaporizer heats flower without burning it. How conduction and convection differ, what temperatures researchers used, and what lab and human studies actually measured.

A dry herb vaporizer heats cannabis flower until its cannabinoids and aromatic compounds turn to vapor, without setting the plant on fire. It's a different device from an oil vape. An oil vape heats a cartridge of extract; a dry herb vaporizer heats the flower itself.

Here's how the devices work, what temperatures researchers used, and what the studies actually measured. If you're comparing oil options instead, our guide to all-in-one vapes and cartridges covers those.

How a dry herb vaporizer works

Every dry herb vaporizer has the same basic parts: a battery or power supply, a heating element, and a chamber, often called the oven, where the ground flower goes. You load the chamber, set a temperature, wait for it to heat, then draw vapor through a mouthpiece.

The key word is heat, not flame. Raw flower holds most of its THC as THCA, which isn't intoxicating until heat converts it. Our explainer on how THCA converts to THC covers that chemistry. A vaporizer does the same conversion a lighter does, at a temperature it controls.

That control showed up clearly in a 2016 lab study published in PLOS ONE. The researchers tested five commercial vaporizers on cannabis flower. The four electric devices, set to 210°C (410°F), converted at least 97% of the THCA to THC. The fifth, heated by a butane flame with no way to set or monitor the temperature, was the only one where the researchers saw signs of combustion: ash and visible smoke.

Conduction vs convection

Close-up of the open heating chamber of a portable vaporizer packed with ground cannabis flower

Vaporizers heat flower in one of two ways, or a mix of both. The retailer Dank Geek describes them this way:

Conduction: the flower touches a hot surface, usually the metal or ceramic wall of the chamber. It heats up quickly, but it can heat unevenly if the chamber is packed tight, and the flower can scorch if it isn't stirred.
Convection: hot air passes through the flower, more like an oven. It heats more evenly, with fewer hot spots, but usually takes a little longer to warm up.

Some devices use a hybrid of the two. None of the studies below compared conduction with convection; what they do show is the value of a controlled temperature.

The temperatures researchers used

You'll see a lot of confident temperature charts online. The studies themselves used a fairly narrow band.

In the 2016 PLOS ONE study, every electric vaporizer was set to 210°C (410°F).
A 2006 study in the Journal of Pharmaceutical Sciences tested the Volcano, a tabletop vaporizer with settings from 130°C to 226°C. The researchers found the highest setting gave the best THC delivery, and that THC release peaked after about two minutes of heating.
A 2007 University of California, San Francisco study heated cannabis to between 180°C and 200°C, just short of combustion.

Those numbers describe what worked in a lab, not a personal recommendation. Device thermostats differ, and a setting on one vaporizer may not match the same number on another.

How much THC actually comes out

A vaporizer doesn't release everything in the chamber. In the 2016 study, the share of the flower's total THC recovered in the vapor ranged from about 55% to 83%, depending on the device. The 2006 Volcano study found an average of about 54% of the loaded THC reached the device's collection balloon, and the researchers detected no breakdown products when they vaporized pure THC.

Those figures measure what a device delivers into its mouthpiece or bag. They don't measure what a person absorbs, which depends heavily on how deeply and how long someone inhales.

What studies found in people

A clean clinical research room with a tabletop vaporizer and a clipboard on a white counter

Two human studies compared vaporizing with smoking directly.

In the 2007 UCSF study, 18 people stayed in a hospital research ward and used cannabis both ways on different days. The researchers reported that blood THC levels were comparable between vaporizing and smoking at every strength tested. Smoking raised the carbon monoxide in participants' breath, as expected. Vaporizing caused little or no increase, which the researchers used as a marker of exposure to combustion products. A significant majority of participants preferred vaporizing.

The second study is the one new users should know about. In a 2018 trial at Johns Hopkins, published in JAMA Network Open, 17 adults who rarely used cannabis inhaled the same doses of THC by vaporizer and by pipe. At the same dose, vaporized cannabis produced stronger effects and higher blood THC than smoked cannabis. At the higher dose, two participants vomited after vaporizing, and another had hallucinations, according to Johns Hopkins.

The researchers' takeaway was practical: people who don't use cannabis often need to be careful about how much they use with a vaporizer. If you're switching from a joint or a pipe, don't assume a vaporizer session will feel the same as what you're used to.

What a vaporizer doesn't change

A vaporizer changes how flower is heated. It doesn't change the rules about where you can use it. In California, the law that bans smoking cannabis in public places counts vaporizers as smoking. Our guide to where you can smoke weed in California explains what that covers.

It also doesn't settle every health question. The studies above measured specific things, such as carbon monoxide, cannabinoid delivery and short-term effects, in small groups of people. None of them followed users over years. If you're comparing vaporizers with water pipes, our guide to choosing a pipe or bong covers the one well-known lab comparison of the two, with its limits.

Grind matters too. Vaporizer chambers are loaded with ground flower, and Dank Geek notes that packing a conduction chamber too tightly can make it heat unevenly. Our guide to choosing a cannabis grinder covers the main types.

Sources

Medicinal Cannabis: In Vitro Validation of Vaporizers for the Smoke-Free Inhalation of Cannabis, Lanz, Mattsson, Soydaner and Brenneisen, PLOS ONE, 2016
Evaluation of a Vaporizing Device (Volcano) for the Pulmonary Administration of Tetrahydrocannabinol, Hazekamp et al., Journal of Pharmaceutical Sciences, 2006
Vaporization as a Smokeless Cannabis Delivery System: A Pilot Study, Abrams et al., Clinical Pharmacology and Therapeutics, 2007
News release on the vaporizer study, University of California, San Francisco, May 15, 2007
Acute Effects of Smoked and Vaporized Cannabis in Healthy Adults Who Infrequently Use Cannabis, Spindle et al., JAMA Network Open, 2018
Vaping Cannabis Produces Stronger Effects Than Smoking Cannabis for Infrequent Users, Johns Hopkins Medicine, 2018
Convection vs. Conduction Heating: What's the Difference?, Dank Geek

This article is general information for adults 21 and older and is not medical advice. Information is current as of October 18, 2026.

Beginners Research

FREQUENTLY ASKED QUESTIONS

What is a dry herb vaporizer?: It's a device that heats cannabis flower until its cannabinoids and aromatic compounds turn to vapor, without burning the plant. It's different from an oil vape, which heats a cartridge of cannabis extract.
How do you use a dry herb vaporizer?: Grind the flower, load it into the chamber, set the temperature and wait for the device to heat up, then draw vapor through the mouthpiece. If you're new to it or switching from smoking, start with less than you're used to.
What's the difference between conduction and convection vaporizers?: Conduction heats flower by direct contact with a hot chamber wall, which is fast but can be uneven. Convection passes hot air through the flower, which heats more evenly but usually takes longer to warm up. Many devices combine both.
What temperature do dry herb vaporizers use?: Studies have used roughly 180°C to 226°C (356°F to 439°F). A 2016 lab study set every electric vaporizer to 210°C (410°F). Device thermostats vary, so the same number may not mean the same heat on every model.
Does a vaporizer burn the flower?: A temperature-controlled electric vaporizer shouldn't. In a 2016 lab study, only a flame-heated device with no temperature control showed signs of combustion such as ash and visible smoke.
Is vaping flower stronger than smoking it?: In a 2018 Johns Hopkins study of people who rarely use cannabis, the same dose produced stronger effects and higher blood THC when vaporized than when smoked. The researchers cautioned infrequent users to be careful with how much they use.
Is vaporizing safer than smoking?: The research doesn't settle that. A 2007 study found vaporizing caused little or no rise in exhaled carbon monoxide, a marker of combustion, compared with smoking. But the studies were small and short, and none followed people over the long term.
Can I use a vaporizer in public in California?: Generally no. California's ban on smoking cannabis in public places counts vaporizers as smoking.