AHCC (Active Hexose Correlated Compound) is a proprietary extract obtained from the mycelia of shiitake mushrooms and related species. It has gained attention for its potential immunomodulatory effects, particularly in the context of viral infections. Several preclinical and limited clinical studies suggest that AHCC can enhance innate and adaptive immune responses, including increased activity of natural killer (NK) cells, dendritic cells, and T lymphocytes.

Some small-scale human studies and case reports have evaluated the effect of AHCC supplementation on viral infections such as human papillomavirus (HPV), hepatitis C, and influenza. For example, a pilot clinical trial published in Frontiers in Oncology (2019) found that AHCC supplementation resulted in a higher rate of HPV clearance compared to placebo in women with persistent HPV infections. Animal studies have also demonstrated enhanced survival and reduced viral loads in influenza-infected mice treated with AHCC.

Despite these findings, high-quality, large-scale randomized controlled trials (RCTs) in humans are lacking. Most evidence comes from preclinical studies, small pilot studies, and open-label trials, which limits the strength of recommendations. Thus, while there is some scientific support for AHCC’s use in supporting immune function during viral infections, the evidence remains preliminary and further research is needed to establish efficacy and safety.