γ-Secretase modulator 12 (Compound 1a) is a selective compound that effectively reduces amyloid-β42 (Aβ42) levels with an IC50 of 0.39 μM. It is specifically designed for Alzheimer’s disease research. Notably, γ-Secretase modulator 12 exhibits a favorable brain/plasma ratio (Kp, brain = 0.72) in mice [1].