When the FDA put out the call for new studies on the safety of CBD last March, the CBD industry quickly responded. A group of ten CBD brands (including industry leaders like Charlotte’s Web, CBDistillery, and Medterra CBD) banded together to support a study designed by Validcare, a Colorado-based clinical research company.
The focus of the study was on the burning question of the effect of CBD on the liver. An early animal study had shown that (extremely) high levels of CBD had caused decreased liver function in mice, and the question of whether the same could be true for humans has cast a bit of a shadow over CBD’s otherwise stellar safety profile.
It seemed highly unlikely that CBD taken in the moderate amounts that most CBD users dose with would cause liver toxicity. (The study in question used doses of CBD of up to 615 mg/ kilo of body weight, which is…staggeringly high.) Nevertheless, the question of liver toxicity has certainly been one issue that the FDA has flagged as needing further study.
With FDA regulation seemingly being held back by these questions of safety to the liver, the industry was eager to participate in a study that could help put the issue to rest.
According to co-investigator Jeff Lombardo, a pharmacist with a specialty in toxicology, the primary purpose of the study was “to observe potential liver effects in adults ingesting oral forms of hemp-derived CBD for a minimum of 60 days.”
The twelve CBD companies involved in the study each recruited up to 100 consumers through their websites. These volunteers were then vetted by Validcare to ensure that they met the inclusion criteria for the study. Altogether, 839 customers qualified to participate in the study.
The FDA has been asking for evidence of CBD's safety - in particular for the liver. This large-scale clinical study showed no evidence of liver toxicity with daily use of CBD.
Companies provided lot-specific product information (so it was clear what each participant was ingesting) and the study participants provided blood samples at a lab close to their homes. The entire study was conducted between August 2020 and February 2021, and the results have yet to be published in a peer-reviewed journal.
However, Validcare has released the preliminary study results, and they look very promising. According to Lombardo, “What we observed to date is no clinical evidence of liver disease in any participants.”
According to a press release, the results did show “slight, clinically insignificant elevations of liver function tests in less than ten percent of consumers irrespective of age, product composition, and form and the amount consumed.”
Of more concern were the three of the 839 participants that had three times the normal levels of the liver enzyme ALT. However, all of these three consumers reported taking prescription medications that are known to elevate liver enzymes, so this is likely not related to CBD consumption at all.
Nevertheless, Lombardo states that Validcare will be investigating whether prescribed medications or other factors contribute to these outliers.
Researchers also discovered that almost 70% of the study participants had medical conditions and were taking medications for those listed conditions – but without an attendant increase of adverse side effects. For context, studies of similar populations would be expected to demonstrate an 11% elevation in liver function tests.
“This unexpected, positive finding makes the data even more compelling and provides significant data to consider secondary safety measurements in the general population,” said Keith Aqua, MD, co-principal investigator of this IRB-approved study.
Validcare will be adding a second cohort to the study in order to increase statistical certainty for liver safety – and they will continue to include diverse populations and consumers with various medical conditions.
These preliminary findings are very encouraging for the CBD industry, as well as helpful for the scientists studying CBD as a treatment for multiple conditions. And, of course, they should help the FDA move towards publishing a regulatory framework for the industry, providing much-needed stability and consumer confidence.