IntroductionFirst line pharmacological treatments for bipolar disorder (BD) can leave shortfalls in recovery leading to patients seeking alternative and adjunctive treatments such as nutraceuticals. This protocol for a systematic review and proposed meta-analysis aims to answer the research question: in patients with BD, how does use of nutraceutical treatments compare with placebo in reducing depressive and mania symptoms?Methods and analysisClinical trials will be identified through database searches using PubMed via PubMed, EMBASE via embase.com, Cochrane Central Register of Controlled Clinical Trials (CENTRAL) via cochranelibrary.com and CINAHL Complete via EBSCO. Search terms for BD and specific nutraceuticals (75 total search terms) will be used. Double-blind, randomised, controlled, clinical trials of adults with BD will be included in the review. Risk of bias will be assessed using the Cochrane Collaboration’s tool for assessing risk of bias in randomised trials.Ethics and disseminationThis review will only look at published data (already reviewed for ethical compliance); therefore, ethical approval is not required. We aim to publish the systematic review in a peer-reviewed journal and present at conferences.PROSPERO registration numberCRD42019100745.