Reishi is a mushroom often used in “Eastern” medicine where Reishi is the Japanese name and Lingzhi is Chinese. Mostly profiled as an immune system booster for those who are already ill, there is some interesting research behind this with reference to stimulus of white blood cells (lymphocytes).
Reishi can affect the gene pathway expression of cells and has in the hyperlinked study shown to reorganize cells in a way that white blood cells can become stronger. This can furthermore increase the activity of the white blood cells, meaning that there is a greater chance to fight diseases.
Furthermore, Reishi has shown in a placebo controlled study to reduce fatigue symptoms amongst patients with neurasthenia. During this 8 week study, 132 chinese neurasthenia patients received either placebo or Reishi and the control group of Reishi consumers showed (via Clinical Global Impression severity scores) results of reduced fatigue.