MAPT and amyotrophic lateral sclerosis: Metformin reduces the burden and toxicity of pathological proteins, including Aβ, p-tau, α-syn and HTT, protects neurons, and enhances cognitive and motor function in multiple animal models.423,424 Notably, metformin also improves behaviour and pathology in ALS/FTD mice.425 In contrast, metformin has adverse effects in some studies.