https://www.selleckchem.com/products/cd38-inhibitor-1.html Hair loss is a common complication after metabolic and bariatric surgery (MBS). There is a lack of published systematic review in the scientific literature on this topic. The aim of this study was to perform a systematic review and meta-analysis on hair loss after MBS in accordance with Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. PubMed, CINAHL, EMBASE, Web of Science, SCOPUS, and four Chinese databases were searched. Data were pooled using Review Manager 5.3 and Stata 12.0, and subgroups were performed if necessary and feasible. A total of 18 studies (n = 2538) were included. The pooled results showed that the incidence of hair loss after MBS was 57% (95% CI 42-71%). It decreased with longer follow-up times. Hair loss was significantly more common in younger (mean difference (MD), - 2.45; 95% CI, - 4.26 to - 0.64; p = 0.008) women (OR, 3.87; 95% CI, 0.59 to 17.59; p = 0.08). Serum zinc (standardized mean difference (SMD), - 1.13; 95% CI, - 2.27 to 0.01, p = 0.05), folic acid (SMD = - 0.88, 95% CI - 1.29 to - 0.46, p < 0.0001), and ferritin levels (SMD, - 0.22; 95% CI, - 0.38 to - 0.05; p = 0.01), but not serum iron and vitamin B , were associated with hair loss following MBS. Hair loss is common after MBS especially in younger women, and those with low serum levels of zinc, folic acid, and ferritin. Prospective studies on larger cohorts are needed. Hair loss is common after MBS especially in younger women, and those with low serum levels of zinc, folic acid, and ferritin. Prospective studies on larger cohorts are needed. Hundreds of thousands of patient-safety clinical incidents are reported to the National Reporting and Learning System (NRLS) database in England and Wales every year. The purpose of this study was to identify bariatric surgery-related learning points from these incidents. We analysed bariatric surgery-related clinical incidents reported to the NRL