Background: Choline alphoscerate (alpha glyceryl phosphorylcholine, α-GPC) is a choline-containing phospholipid used as a medicine or nutraceutical to improve cognitive function impairment occurring in neurological conditions including adult-onset dementia disorders. Despite its 1985 marketing authorization, there are still discrepancies between countries regarding its approval as a prescription medicine and discussions about its effectiveness. Objective: This study aimed to evaluate the efficacy of the α-GPC compound for treating cognitive impairment in patients with adult-onset neurological disorders. Methods: Relevant studies were identified by searching PubMed, Web of Science, and Embase. Studies that evaluated the effects of α-GPC alone or in combination with other compounds on adult-onset cognitive impairment reporting cognition, function, and behavior were considered. We assessed the risk of bias of selected studies using the Cochrane risk of bias tool. Results: A total of 1,326 studies and 300 full-text articles were screened. We included seven randomized controlled trials (RCTs) and one prospective cohort study that met our eligibility criteria. We found significant effects of α-GPC in combination with donepezil on cognition [4 RCTs, mean difference (MD):1.72, 95% confidence interval (CI): 0.20 to 3.25], functional outcomes [3 RCTs, MD:0.79, 95% CI: 0.34 to 1.23], and behavioral outcomes [4 RCTs; MD: –7.61, 95% CI: –10.31 to –4.91]. We also observed that patients who received α-GPC had significantly better cognition than those who received either placebo or other medications [MD: 3.50, 95% CI: 0.36 to 6.63]. Conclusion: α-GPC alone or in combination with donepezil improved cognition, behavior, and functional outcomes among patients with neurological conditions associated with cerebrovascular injury.