Vaporized CBD produces much higher blood levels than oral CBD, and pure CBD does not convert to THC in the body
Vaporized CBD reached peak blood concentrations 8-12 times higher than oral CBD at the same 100 mg dose, and neither route produced detectable THC or its metabolites.
Quick Facts
What This Study Found
Mean peak CBD blood concentration was 171.1 ng/mL for vaporized CBD-dominant cannabis, 104.6 ng/mL for vaporized pure CBD, and only 13.7 ng/mL for oral CBD. Among oral formulations, Epidiolex produced the highest peak (20.5 ng/mL) vs. capsule (17.8 ng/mL) and syrup (2.8 ng/mL). Pure CBD by either route did not produce detectable THC or THC-COOH in blood.
Key Numbers
Peak CBD: vaporized cannabis 171.1 ng/mL (range 40-665), vaporized pure CBD 104.6 ng/mL (range 19-312), oral CBD 13.7 ng/mL (range 0-50). THC detected in 12/18 after vaporized CBD-dominant cannabis but in 0/18 after pure CBD products.
How They Did This
Within-subject, double-blind, double-dummy, placebo-controlled study in 18 adults. Each participant received 100 mg CBD via oral, vaporized, and vaporized CBD-dominant cannabis (10.5% CBD/0.39% THC) routes, plus placebo. Blood and oral fluid were collected for 57-58 hours post-dose.
Why This Research Matters
Massive differences in bioavailability between oral and vaporized CBD have direct implications for dosing, product selection, and drug testing. The confirmation that pure CBD does not convert to THC addresses a common concern.
The Bigger Picture
These pharmacokinetic differences explain why vaporized and oral CBD may produce different clinical effects and why research findings from one route may not apply to another. The absence of THC conversion is reassuring for workplace drug testing.
What This Study Doesn't Tell Us
Small sample size (n=18). Single-dose study. Limited to three oral formulations. Fasting condition only tested in 6 participants. May not reflect real-world use patterns with repeated dosing.
Questions This Raises
- ?Do the higher blood levels from vaporization translate to greater therapeutic effects?
- ?Would repeated dosing change the pharmacokinetic profile?
- ?Should CBD dosing recommendations differ by route?
Trust & Context
- Key Stat:
- Vaporized CBD peak: 171 ng/mL vs. oral: 14 ng/mL
- Evidence Grade:
- Well-designed within-subject RCT with multiple comparisons, limited by small sample size.
- Study Age:
- Published in 2022.
- Original Title:
- Pharmacokinetic Profile of ∆9-Tetrahydrocannabinol, Cannabidiol and Metabolites in Blood following Vaporization and Oral Ingestion of Cannabidiol Products.
- Published In:
- Journal of analytical toxicology, 46(6), 583-591 (2022)
- Authors:
- Bergeria, Cecilia L(7), Spindle, Tory R(18), Cone, Edward J(11), Sholler, Dennis, Goffi, Elia, Mitchell, John M, Winecker, Ruth E, Bigelow, George E, Flegel, Ronald, Vandrey, Ryan
- Database ID:
- RTHC-03707
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
Will taking CBD cause a positive drug test for THC?
In this study, pure CBD products (both oral and vaporized) did not produce detectable THC or its metabolite THC-COOH in blood. However, vaporized CBD-dominant cannabis containing 0.39% THC did produce detectable THC in 12 of 18 participants.
Why does vaporized CBD produce higher blood levels than oral CBD?
Inhaled CBD enters the bloodstream directly through the lungs, bypassing the digestive system and liver where oral CBD is extensively broken down before reaching circulation (first-pass metabolism).
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Cite This Study
https://rethinkthc.com/research/RTHC-03707APA
Bergeria, Cecilia L; Spindle, Tory R; Cone, Edward J; Sholler, Dennis; Goffi, Elia; Mitchell, John M; Winecker, Ruth E; Bigelow, George E; Flegel, Ronald; Vandrey, Ryan. (2022). Pharmacokinetic Profile of ∆9-Tetrahydrocannabinol, Cannabidiol and Metabolites in Blood following Vaporization and Oral Ingestion of Cannabidiol Products.. Journal of analytical toxicology, 46(6), 583-591. https://doi.org/10.1093/jat/bkab124
MLA
Bergeria, Cecilia L, et al. "Pharmacokinetic Profile of ∆9-Tetrahydrocannabinol, Cannabidiol and Metabolites in Blood following Vaporization and Oral Ingestion of Cannabidiol Products.." Journal of analytical toxicology, 2022. https://doi.org/10.1093/jat/bkab124
RethinkTHC
RethinkTHC Research Database. "Pharmacokinetic Profile of ∆9-Tetrahydrocannabinol, Cannabid..." RTHC-03707. Retrieved from https://rethinkthc.com/research/bergeria-2022-pharmacokinetic-profile-of-9tetrahydrocannabinol
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.