Active Hexose Correlated Compound (AHCC) is a mushroom-derived compound often marketed as an immune support supplement. Its use for influenza is primarily supported by preclinical scientific evidence rather than long-standing traditional use or robust clinical trials. Several animal studies have investigated AHCC's effects on influenza infection. For example, research in mice has indicated that AHCC supplementation can enhance the immune response, leading to a reduction in viral load and improved survival following influenza virus challenge. The proposed mechanism involves modulation of innate and adaptive immune responses, particularly by increasing activity of natural killer (NK) cells and cytokine production.

However, while these findings are promising, the evidence is limited by the fact that most studies are preclinical, and high-quality, peer-reviewed human clinical trials specifically assessing AHCC for influenza prevention or treatment are lacking. Some small pilot studies suggest immune-modulating effects in humans, but direct evidence for efficacy against influenza in people is insufficient. Therefore, while AHCC has a scientific rationale and some preliminary data supporting its use in influenza, the strength of the evidence is modest and does not currently justify routine clinical use for influenza without further research.