Across 4 studies, 2 reported beneficial effects on interleukin-6 levels, while 2 found no significant effect; the predominant effect size was mixed (small to large). The evidence base includes meta-analyses in clinical populations with type 2 diabetes, but no consistent dose range or duration was reported. Overall, propolis shows mixed evidence for reducing IL-6, with findings varying by study design and population.
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 two beneficial studies showed a large effect (SMD = -3.47) and a small effect (WMD = 1.52 pg/mL), respectively, indicating substantial heterogeneity. Dose and form data were not reported in the available abstracts, limiting practical guidance.
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)