Effects of curcumin on depression, anxiety, and stress symptoms in adults: a GRADE-assessed systematic review and dose-response meta-analysis

BACKGROUND: Curcumin, a bioactive polyphenol extracted from Curcuma longa, has demonstrated antioxidant, anti-inflammatory, and neuroprotective properties that may benefit mental health. However, evidence from randomized controlled trials (RCTs) remains inconsistent. OBJECTIVE: This systematic review and dose-response meta-analysis aimed to quantitatively assess the effects of curcumin supplementation on depression, anxiety, and stress in adults. METHODS: Electronic databases including PubMed, Scopus, Web of Science, and Google Scholar were searched up to December 2025 for RCTs. Two reviewers independently conducted study selection, data extraction, and risk-of-bias assessment. Pooled standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated. Subgroup, meta-regression, sensitivity, dose-response, and time-response analyses were conducted. Moreover, publication bias and certainty of evidence were evaluated. The study protocol was registered in the PROSPERO database (CRD420251208049). RESULTS: Twenty-six RCTs encompassing 1,491 participants were included. Curcumin supplementation significantly reduced symptoms of depression (SMD = -1.53; 95% CI: -2.05 to -1.02), anxiety (SMD = -1.67; 95% CI: -2.42 to -0.93), and stress (SMD = -1.71; 95% CI: -3.37 to -0.06) compared with placebo. Dose-response analysis indicated a significant nonlinear association, suggesting that higher curcumin doses (>1.5 g/day) were associated with greater reductions in depressive symptoms. Subgroup analyses showed slightly greater improvements among female participants and those experiencing psychological distress. CONCLUSIONS: Curcumin supplementation may provide a potential benefit for depression, anxiety, and stress; however, substantial between-study heterogeneity and moderate-to-low certainty of evidence limit confidence in the generalizability of these findings. Further well-designed RCTs are warranted to confirm these findings.