Oxidative stress has been proposed as a factor in many conditions, such as Alzheimer’s disease. Moreover, there is a link between oxidative stress and a variety of COVID-19 symptoms. The occurrence of multiple diseases can be ascribed to longterm exposure to heightened oxidative stress impeding the body’s normal homeostatic function. Complications arising from elevated levels of oxidative stress include lipid peroxidation, mitochondrial dysfunction, protein oxidation, damage to deoxyribonucleic acid (DNA), glycoxidation, weakened antioxidant defence, and impaired amyloid clearance. Moreover, oxidative stress leads to the onset of inflammation through an increase in the levels of active inflammatory factors. It is widely accepted that the prolongation of this detrimental cycle contributes to the development of pathological states. Consequently, interruption of the cycle of oxidative stress is imperative to prevent disease onset. Research has primarily focused on individual antioxidants, with an emphasis on vitamins C and E, owing to their significant properties as antioxidants that help reduce oxidative stress. Compared to individual antioxidants, supplements encompassing a harmonious assortment mixture of multiple antioxidants may be more effective in combating various symptoms associated with pre-existing conditions and current health concerns like COVID-19 and Alzheimer’s disease. This review explores the correlation between oxidative stress, COVID-19 infection, and Alzheimer’s disease. Additionally, we suggest the use of Twendee X, a remarkably powerful antioxidant compound, to reduce the rate of cognitive decline in individuals with Alzheimer’s disease. Moreover, Twendee X can prevent and alleviate COVID-19 and its associated symptoms.