In 6 cancer cell lines, pure CBD matched or outperformed 3 commercial CBD oils at reducing cancer cell viability, and some oils actually appeared to protect cancer cells from CBD effects.
Oncology researchers, CBD product developers, and patients considering CBD for cancer-related use.
Pure CBD outperformed all 3 CBD oils; some oils protected cancer cells
What the researchers found
Pure CBD (10 μM) reduced cell viability in 3 of 6 cancer cell lines tested. None of the 3 commercial CBD oils reduced viability more than pure CBD. Dose-response curves showed lower IC50 values (higher potency) for pure CBD compared to the most potent oil. Some oils appeared to protect cancer cells from CBD effects. The anti-cancer activity was cell-line specific rather than cancer-type specific.
Why it matters
The "entourage effect" is frequently cited to argue that whole-plant cannabis products are superior to purified compounds. This study provides direct evidence against that claim for anti-cancer activity, finding pure CBD was equal or superior.
The numbers in context
6 cancer cell lines; 3 cancer types; 10 μM CBD; 3 commercial oils; pure CBD effective in 3 of 6 lines; some oils appeared protective of cancer cells.
How the study worked
In vitro study testing pure CBD and 3 commercial CBD hemp oils (independently verified for CBD content and cannabinoid/terpene composition) against 6 human cancer cell lines from 3 cancer types using MTS viability assay and dose-response curves.
What this study cannot tell us
In vitro only (does not reflect in vivo tumor biology); limited to 6 cell lines; only tested one CBD concentration initially; commercial oils vary in composition; anti-cancer cell viability is not the same as treating cancer in patients.
How to read the evidence
Preliminary: in vitro only; novel finding but limited to cell culture conditions.
When this study was published
Published 2020.
The bigger picture
The finding that some CBD oils actually protected cancer cells is concerning. Other compounds in whole-plant extracts may interfere with CBD anti-cancer activity. This challenges assumptions about the superiority of full-spectrum products.
Questions still open
- Which non-CBD compounds in oils protect cancer cells? Does the entourage effect hold for other CBD applications (pain, anxiety) even if not for cancer?
Common questions
Is CBD oil better than pure CBD for fighting cancer?
Does this disprove the entourage effect?
Read the original research
Cannabidiol (CBD) Oil Does Not Display an Entourage Effect in Reducing Cancer Cell Viability in vitro.
Medical cannabis and cannabinoids, 3(2), 95-102
Citation
Raup-Konsavage, Wesley M; Carkaci-Salli, Nurgul; Greenland, Kelly; Gearhart, Robert; Vrana, Kent E. (2020). Cannabidiol (CBD) Oil Does Not Display an Entourage Effect in Reducing Cancer Cell Viability in vitro.. Medical cannabis and cannabinoids, 3(2), 95-102. https://doi.org/10.1159/000510256
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