Across 4 studies, results are mixed: 2 reported beneficial effects of propolis on reducing interleukin-6 levels (one with a large effect size, one with a small effect), while 2 high-quality systematic reviews found neutral effects. The predominant effect size is mixed (small to large), with the strongest signal coming from a 2024 meta-analysis reporting a large effect (SMD = -3.47, p < 0.001). Doses, forms, and study durations were not consistently reported across studies, limiting the ability to identify effective dose ranges or treatment durations.
Caveats: Evidence base is small (only 4 studies) — conclusions should be considered preliminary. Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. The largest and highest-quality review (2025 systematic review, n=731, evidence score 6) found no significant effect on IL-6 in T2DM patients, contrasting with a smaller 2024 meta-analysis that reported a strong benefit. Doses and forms were not specified in available abstracts, making it impossible to identify effective regimens or isolate form-specific effects.
no significant effects were observed for ... interleukin-6 (IL-6)
there were no significant effects on ... IL-2 ... in comparison to the control group
The overall estimate indicated that the propolis significantly reduced serum levels of IL-6 (SMD = -3.47, 95% confidence interval (95%CI): -5.1, -1.84; p < 0.001)
interleukin 6 (IL-6) (WMD: 1.52 pg/mL)