Vaporizing marijuana means heating cannabis flower or oil enough to release cannabinoids as vapor without setting it on fire. A small hospital study found that vaporizing delivered similar peak THC to smoking with lower carbon monoxide, but vaping has its own safety record, most notably the 2019 EVALI outbreak. Buy only licensed, lab-tested products.
Vaporizers are one of the most common alternatives to smoking, and they have been studied for close to two decades. This guide explains how they work, what the research shows, what went wrong in 2019, and how to choose a device and product sensibly. Our Cannabis 101 section covers other methods.
How Vaporizing Works
Smoking burns plant material, and burning produces smoke. A vaporizer heats the material to a lower temperature, so cannabinoids turn into vapor before the plant combusts. NIDA lists dry herb vaporizers and vape pens as the main devices people use. They fall into two groups:
- Dry herb vaporizers heat ground cannabis flower. Desktop units like the Volcano used in early research and portable units both fit here.
- Oil and concentrate vaporizers heat a cartridge of cannabis oil or a small amount of concentrate. These are usually the most potent option.
What the Research Shows
The best-known early test was a pilot study led by Donald Abrams at the University of California, San Francisco. Published in 2007 in Clinical Pharmacology and Therapeutics, it enrolled 18 inpatients at San Francisco General Hospital. Each received cannabis at three THC strengths, either smoked or vaporized with a Volcano device (PubMed record).
| Finding | Result |
|---|---|
| Carbon monoxide in exhaled breath | Lower with vaporization than with smoking |
| Peak THC in blood | Similar between methods |
| THC levels 30 minutes after dosing and later | Higher with vaporization |
| Preference | 14 preferred vaporizing, 2 preferred smoking, 2 had no preference |
| Adverse events | None observed |
Researchers used carbon monoxide as a marker for the many toxic gases produced by combustion. The authors concluded vaporization was a safe and effective way to deliver THC and suggested it could serve as a smokeless delivery method in future trials.
Keep the limits in view. This was 18 people, and it measured a stand-in (carbon monoxide), not long-term lung outcomes. It does not show that vaping is safe over years. The CDC states that smoked cannabis can harm lung tissue; whether long-term vaporizing is meaningfully gentler on the lungs is not something that study settles.
The 2019 EVALI Outbreak: Why Source Matters
In 2019 the United States saw a sharp rise in lung injuries tied to vaping. CDC named the condition EVALI, for e-cigarette or vaping product use-associated lung injury. The agency’s summary (page dated February 25, 2020) reports:
- As of February 18, 2020, 2,807 hospitalized cases or deaths from all 50 states, D.C. and two territories, including 68 confirmed deaths.
- Vaping-related emergency department visits rose sharply in August 2019, peaked in September 2019 and declined afterward.
- Of 2,022 hospitalized patients with substance-use data, 82% reported using THC-containing products.
- Among THC users who reported a source, 78% got products only from informal sources, 16% only from commercial sources and 6% from both.
- Vitamin E acetate was found in lung fluid from 48 of 51 EVALI patients tested, and not in the comparison group.
CDC and FDA recommend avoiding THC-containing vaping products, particularly from informal sources like friends, family or in-person or online dealers, and say vitamin E acetate should not be added to any vaping product. Read the CDC summary.
How to Vape More Safely
- Buy from a licensed store. In Washington, certified labs report potency, and pesticide testing applies to cannabis products under WAC 314-55-102 and the Liquor and Cannabis Board’s 2022 rules. Use our Washington and Oregon directories.
- Skip anything unlabeled. A cartridge with no store, no batch information and no test results is exactly the profile CDC warned about.
- Do not add anything to a cartridge or oil. CDC says vitamin E acetate should not be added to any vaping product, and the same caution makes sense for any other additive.
- Start with a small puff. Concentrates deliver large amounts of THC quickly, which NIDA says raises the risk of negative effects.
- Do not drive after use. The CDC says cannabis can slow reaction time and the ability to make decisions.
What to Check Before You Buy a Cartridge or Device
- The licensee and package label. A real product shows the producer, a batch or lot identifier and the THC content. If any of that is missing, leave it on the shelf.
- The ingredient list. Ask the budtender what is in the oil. Products made from cannabis extract and, where the label says so, cannabis-derived terpenes are easier to evaluate than mystery blends.
- The hardware. Use a battery and charger meant for the device, and stop using any device that overheats or leaks.
- The dose. A strong cartridge is not a reason to take long pulls. Our dosage guide explains why starting small works.
Vaporizer vs. Joint, Bong or Blunt
| Method | Burns plant material? | Evidence in this guide |
|---|---|---|
| Joint, blunt, pipe, bong | Yes | CDC: smoked cannabis can harm lung tissue |
| Dry herb vaporizer | No (heated) | Small 2007 study: lower exhaled CO, similar peak THC |
| Oil cartridge | No (heated oil) | EVALI cases concentrated in informal-source THC products |
If you smoke, see our guides to blunts, joints and roaches and consuming weed without smoking.
Legal Notes
Using cannabis in public in Washington is a civil infraction, so vape at home or where it is allowed. See the Washington and Oregon law guides. Taking cannabis across state lines is illegal under federal law; read our federal law overview.
Vaporizing Marijuana FAQ
Is vaporizing marijuana safer than smoking?
It looked gentler in one measured way: a 2007 study of 18 patients found less exhaled carbon monoxide with a vaporizer. Long-term lung outcomes were not tested, so it is not proven safe.
Does vaping weed get you higher?
In the Abrams study, peak THC in blood was similar between smoking and vaping, though later levels were higher with vaporization. How strong it feels depends on the product and amount.
What was EVALI?
EVALI is the lung injury CDC tracked during the 2019 outbreak. CDC counted 2,807 hospitalized cases or deaths, including 68 deaths, by February 2020, with most patients reporting THC product use.
How do I avoid unsafe vape cartridges?
Buy only licensed, tested products from a state-licensed store, and avoid cartridges from friends, family or dealers, as CDC advises.
Is a dry herb vaporizer different from a vape pen?
Yes. Dry herb devices heat ground flower; pens heat oil in a cartridge. The EVALI warnings concern THC oil products from informal sources.
Can I vape cannabis in public?
Not in Washington, where public use is a civil infraction. Check local rules in Oregon.
For adults 21+ in legal states. General information, not medical advice.
