A 2026 animal study compared cannabidiol (CBD) and cannabigerol (CBG) in rats exposed to excessive iron early in life, a model associated with long-term memory problems, neuroinflammation, and changes in the blood–brain barrier. As adults, the rats received CBD, CBG, or a control treatment for 21 days. Researchers then evaluated recognition memory, inflammatory markers in the hippocampus, and occludin, a protein that helps maintain the tight junctions of the blood–brain barrier. Both CBD and CBG improved recognition memory in iron-exposed rats.

The two cannabinoids also affected inflammation and blood–brain barrier markers. Both reduced the inflammatory marker IL-1β in iron-exposed animals, although their effects on other inflammatory signals differed. Iron overload had reduced levels of occludin, suggesting damage to blood–brain barrier integrity. Treatment with either CBD or CBG restored occludin expression, with CBG producing a particularly strong effect in this measure. The researchers concluded that CBD and CBG appear to act through distinct but complementary mechanisms involving inflammation and blood–brain barrier regulation.

These findings suggest that CBD and CBG may have neuroprotective potential in conditions where excess iron, inflammation, and blood–brain barrier disruption contribute to cognitive decline. However, this was an animal study using male rats, and occludin was used as a molecular marker rather than a direct test of blood–brain barrier permeability. Human studies are still needed to determine whether similar effects occur in people and whether these findings could translate into future treatments for neurological disorders.

Source: Kowalski L, Colucci ACM, dos Santos JB, et al. *Differential Effects of Cannabidiol and Cannabigerol on Cognition, Neuroinflammation, and Blood–Brain Barrier Integrity in a Rat Model of Iron Overload*. *Neurotoxicity Research*. 2026;44:48. https://pmc.ncbi.nlm.nih.gov/articles/PMC13524965/