The effects of coenzyme Q10 supplementation on exercise-induced oxidative stress and related physiological outcomes in athletes: a systematic review and meta-analysis.

UNLABELLED: Exercise-induced oxidative stress has been proposed as a mechanistic link between heavy training loads, membrane injury, impaired recovery, and inconsistent performance responses. Coenzyme Q10 (CoQ10), a mitochondrial electron-transport cofactor and lipid-phase antioxidant, is therefore widely promoted as a supportive supplement for athletes, although randomized evidence remains inconsistent. We systematically searched PubMed, Web of Science, Embase, and EBSCOhost from database inception to April 2026 and prospectively registered the review in PROSPERO (CRD420261370320). Randomized parallel-group and crossover trials evaluating oral CoQ10 in athletes or athlete-relevant trained individuals were eligible. Twenty-four studies (613 participants) were included in the systematic review, and 15 studies (330 participants) contributed to at least one quantitative synthesis. Because several studies contributed more than one eligible estimate, the unit of quantitative reporting was the effect size/comparison. Random-effects models were used for meta-analysis. Overall risk of bias was judged as some concerns in 23 of 24 studies (95.8%) and high risk in one study (4.2%). The primary pooled analysis for malondialdehyde (MDA) included seven effect sizes/comparisons from five studies and was not statistically significant (SMD = -0.96, 95% CI -2.07 to 0.15; I² = 73.0%). In the sensitivity analysis, the pooled MDA effect favored CoQ10 (SMD = -0.93, 95% CI -1.65 to -0.22; I² = 73.0%), but this signal remained fragile. The representative pooled physiological outcome, VO₂max, included eight effect sizes/comparisons from seven studies and was neutral (SMD = 0.03, 95% CI -0.32 to 0.39; I² = 0.0%). Supplementary pooled analyses were likewise neutral for blood pressure, creatine kinase, interleukin-6, total antioxidant capacity, tumor necrosis factor-α, and anaerobic threshold. Narrative synthesis, however, suggested more coherent context-dependent signals in studies conducted under marked oxidative or recovery stress. Current evidence does not support a robust overall ergogenic or physiological benefit of CoQ10 supplementation in athletes. The only potentially favorable quantitative signal emerged in the MDA sensitivity analysis; however, this finding should be interpreted cautiously because of residual heterogeneity, small sample sizes, and methodological limitations. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s13205-026-05076-4.