Immunomodulatory effects of a mycelium extract of Cordyceps (Paecilomyces hepiali; CBG-CS-2): a randomized and double-blind clinical trial

Randomized, double-blind, placebo-controlled, parallel-group clinical trial in healthy adults aged 20–75 years. 80 participants randomized (CBG-CS-2 n=40, placebo n=40); final analysis: 39 in CBG-CS-2 and 40 in placebo; mean age 47.6 ± 5.9; 52 men, 28 women.

Cordyceps mycelium extract (Paecilomyces hepiali, CBG-CS-2) 1.68 g/day in capsules, taken as two capsules twice daily after breakfast and dinner for 8 weeks.

NK-cell cytotoxic activity increased by 38.8% (SD 17.6) from baseline in the CBG-CS-2 group, while placebo decreased by 35.5% (SD 19.9%); between-group difference significant (P = 0.019). IFN-γ rose 11.4% (SD 7.1) vs 10.7% (SD 6.7) in placebo; no significant between-group difference for this cytokine. No significant changes in IL-1β, IL-2, IL-4, IL-10, IL-12, or TNF-α. No adverse events; safety parameters within normal ranges. Conclusion: Eight weeks of CBG-CS-2 supplementation safely enhances NK-cell–mediated immunity in healthy adults, with no safety concerns and no pro-inflammatory cytokine increase.

Short duration (8 weeks); healthy adult population without immune challenge; cytokine changes not consistently different between groups; results may not generalize to diseased populations; single-center study; 1 dropout in the intervention group.