Considering the increasing incidence of Alzheimer’s disease (AD) and mild cognitive impairment (MCI) worldwide, there is an urgent need to identify efficacious, safe and convenient treatments. Numerous investigations have been conducted on the use of supplements in this domain, with oral supplementation emerging as a viable therapeutic approach for AD or MCI. Nevertheless, given the multitude of available supplements, it becomes imperative to identify the optimal treatment regimen.

Eight academic databases and three clinical trial registries will be searched from their inception to 1 June 2023. To identify randomised controlled trials investigating the effects of supplements on patients with AD or MCI, two independent reviewers (X-YZ and Y-QL) will extract relevant information from eligible articles, while the risk of bias in the included studies will be assessed using the Rob 2.0 tool developed by the Cochrane Collaboration. The primary outcome of interest is the overall cognitive function. Pair-wise meta-analysis will be conducted using RevMan V.5.3, while network meta-analysis will be carried out using Stata 17.0 and ADDIS 1.16.8. Heterogeneity test, data synthesis and subgroup analysis will be performed if necessary. The GRADE system will be employed to assess the quality of evidence. This study is scheduled to commence on 1 June 2023 and conclude on 1 October 2023.

Ethics approval is not required for systematic review and network meta-analysis. The results will be submitted to a peer-reviewed journal or at a conference.

PROSPERO (CRD42023414700).