Effects of Plant Extract and Dietary Supplements on Tinnitus Perception in Adults: A Systematic Review and Meta-Analysis

Introduction. Tinnitus, the perception of sound without an external source, affects millions worldwide and significantly impacts the health-related quality of life (HRQoL). Despite various management strategies, no universally effective treatment exists. While tinnitus sufferers frequently use dietary supplements, their efficacy remains unclear. This systematic review and meta-analysis evaluated the effectiveness of plant extracts and dietary supplements in treating tinnitus symptoms. Methods. We conducted a systematic search in PubMed for randomized controlled trials (RCTs) and crossover trials comparing plant extracts and dietary supplements with placebo or control groups in adults with tinnitus. Selection criteria included patients with subjective tinnitus and studies examining plant extracts or dietary supplements. Using a random-effects model, we estimated standardized mean differences and odds ratios with 95% confidence intervals (95% CIs). Study quality was assessed using the Revised Cochrane risk-of-bias tool for randomized trials. Protocol registered on PROSPERO (CRD42023446824). Results. Twenty-one studies involving 1,759 participants evaluated four plant extracts and six dietary supplements. Five trials investigated plant extracts (Euterpe oleracea, traditional herbal medicine Hangekobokuto, Neurotec, and caffeine), while sixteen studies examined dietary supplements (melatonin, zinc, alpha-lipoic acid, manganese, vitamin B complex, and nicotinamide). Meta-analysis revealed no significant efficacy for caffeine in reducing tinnitus impact on HRQoL (SMD=0.07; 95% CI: -0.73 to 0.86; I²=0.0%). However, melatonin showed a modest reduction in tinnitus loudness compared to placebo (OR=2.52; 95% CI: 1.33-4.80; k=2, 168 participants). Conclusions. Among the studied interventions, only melatonin showed modest efficacy in reducing tinnitus loudness, though evidence remains uncertain due to methodological limitations. Further high-quality RCTs with larger samples, standardized outcome measures, and long-term follow-up are necessary to confirm these findings and explore melatonin’s potential role in tinnitus management.