It's in the article: "Human cerebral microvascular endothelial cells were cultured and exposed to an amount of erythritol equivalent to consuming a typical bev

It's in the article: "Human cerebral microvascular endothelial cells were cultured and exposed to an amount of erythritol equivalent to consuming a typical beverage. Experimental conditions included five biological replicates per group." So it needs to cross the blood-brain barrier. From the research paper: "Moreover, it is important to note that erythritol does cross the blood brain barrier and interact with the cerebrovasculature". Unclear what percentage this is.