Three Popular Medicinal Mushroom Supplements: A Review of Human Clinical Trials

There are many mushroom supplements on the market claiming a variety of health benefits, and it is difficult to discern which of these claims are backed by reliable research. Most of the existing research is conducted using either human cells or animal models rather than human participants. Without being tested directly on humans, this research has limited application. A review of the literature reveals a relatively small number of studies have been conducted using human patients and those that do exist vary widely in study design and quality. This article brings together all the existing studies that involve human participants for three popular mushroom species that are commonly consumed as dietary supplements. The three species reviewed are Agaricus blazei or royal sun agaric, Inonotus obliquus or chaga, and Ganoderma lucidum or reishi. Each study described includes the study’s design, the condition being treated, the preparation, dosage, and duration of treatment, the number of subjects, and a summary of the results. The outcome of these studies is variable and caution is recommended when extrapolating the results. Many factors — such as poor study design, small sample sizes, lack of replication, mushroom variability, and problematic statistical methods — make it difficult to rely on the results of any individual study. Further research using well-designed clinical trials is needed to establish medicinal benefits for these three mushroom species.