Effects of Coenzyme Q10 Supplementation on Depressive Symptoms and Fatigue

BACKGROUND: Coenzyme Q10 (CoQ10) is a mitochondrial cofactor with antioxidant and anti-inflammatory properties that may counteract mechanisms implicated in depression, such as oxidative stress and mitochondrial dysfunction. We evaluated the efficacy of CoQ10 supplementation on depressive symptoms and fatigue in patients with depression, whether as a primary disorder or in the context of underlying medical illness. METHODS: A systematic review and meta-analysis was conducted according to PRISMA guidelines. Randomized controlled trials comparing CoQ10 with placebo or standard treatment in patients diagnosed with depression were eligible, independent of concomitant medical conditions. Outcomes included changes in depressive symptoms and fatigue. Data were pooled using random-effects models, with standardized mean differences (SMD) and 95% CIs. Heterogeneity was assessed with the I 2 statistic, and sensitivity analyses were performed using a leave-one-out approach. RESULTS: Five RCTs with 474 participants were included. Three trials enrolled patients with depression associated with significant medical conditions-multiple sclerosis, breast cancer, and polycystic ovary syndrome-while 2 included patients with primary depressive disorders (major depression and bipolar disorder). CoQ10 supplementation significantly reduced depressive symptoms compared with control (SMD: -0.68; 95% CI: -1.02 to -0.33; P <0.01; I2 =58%), with consistent results across rating scales. Sensitivity analysis indicated that heterogeneity was largely driven by a single study. No significant benefit was observed for fatigue (SMD: -0.33; 95% CI: -1.38 to 0.72; P =0.54; I2 =89%), based on only 2 trials. CONCLUSIONS: CoQ10 supplementation may confer moderate improvement in depressive symptoms across diverse populations. However, the evidence for fatigue remains inconclusive.