This study investigated the efficacy and safety of a propolis-mangosteen extract complex (PMEC) on gingival health in patients with gingivitis and incipient periodontitis. A multicentered, randomized, double-blind, placebo-controlled trial involving 104 subjects receiving either PMEC or placebo for eight weeks was conducted. The primary focus was on the changes in inflammatory biomarkers from gingival crevicular fluid (GCF), with clinical parameters as secondary outcomes. The results revealed that the PMEC group showed a significantly reduced expression of all measured GCF biomarkers compared to the placebo group (p < 0.0001) at 8 weeks, including substantial reductions in IL-1β, PGE2, MMP-8, and MMP-9 levels compared to the baseline. While clinical parameters trended towards improvement in both groups, the intergroup differences were not statistically significant. No significant adverse events were reported, indicating a favorable safety profile. These findings suggest that PMEC consumption can attenuate gingival inflammation and mitigate periodontal tissue destruction by modulating key inflammatory mediators in gingival tissue. Although PMEC shows promise as a potential adjunctive therapy for supporting gingival health, the discrepancy between biomarker improvements and clinical outcomes warrants further investigation to fully elucidate its therapeutic potential in periodontal health management.