The Spartan Guide to Reishi Mushroom

The Claim

To make an herbal medicine, supplement manufacturers use two parts of reishi mushroom: the fruiting body (what you’d see in the dirt) and the mycelium (the network of fine, white filaments that connects groups of mushrooms). The woody, bitter fungus is then used to bolster the immune system, fight off viruses (such as the flu), and treat heart disease and cancer.

The Evidence

Researchers have studied reishi mushroom extract for handful of conditions, and early results are promising.  They suggest that reishi mushrooms can decrease the symptoms of clogged arteries, such as shortness of breath and chest pain. And taking an extract daily for three months may reduce blood pressure among people whose blood pressure is already extremely high. Not all studies back this effect, thought, and some suggest that the extract doesn’t do much for those with only slightly elevated blood pressure. So as of now, the results still aren't conclusive. 

In addition to the potential heart-helping effect, a budding body of research suggests that reishi mushrooms may reduce the number of tumors in people with colorectal adenomas (noncancerous tumors). They may also help people with hepatitis B and boost the quality of life and immune function in lung cancer patients. “I prescribe the supplement for its antioxidant and anticancer activity,” says Junella Chin, an osteopathic physician in New York City who specializes in functional medicine. How to Use It The extract comes in pill, powder, and liquid form. “Some people get a skin rash, which is an allergic reaction,” Chin notes. So stop use if that happens. And since reishi mushroom extract might lower blood pressure and slow blood clotting, those on blood-pressure medications (such as Vasotec or Lasix) and blood thinners should be careful.