Plasma Aβ40 significantly increased in patients with AD. Plasma AD-related molecules including Aβ40 (A), Aβ42 (B), Aβ42/40 (C), p-Taul81 (D) were examined and compared between cognitively unimpaired (CU) controls and AD. Unpaired Student’s t test, *p < 0.05. n = 19 CU, 24 AD. Sex effect on Aβ40 (E), Aβ42 (F), Aβ42/40 (G), p-Taul81 (H) were compared. Unpaired Student’s t test. n = 16 males, 27 females.