Sucralose’s primary impact on the nervous system is seen in the hypothalamus, the brain region that links sweetness to expected calories.
A 2025 Nature Metabolism trial showed that sucralose consumption increased hypothalamic blood flow and neuronal activity more than sugar or water.
This occurs because sweet taste receptors in the mouth and gut signal to the brain that glucose is on the way, but when no calories arrive, the mismatch triggers abnormal neuronal firing.
As a result, dopamine and serotonin signaling are disrupted, appetite-control circuits are affected, and over time this heightened activity may drive stronger hunger, weaker satiety, and a tendency to overeat.