In 1999, the tree conk Hemlock Varnish Shelf was found to possess “the strongest antioxidant activity of five species of Ganoderma [Reishi] tested.” It was found to have stronger antioxidative activity than Vitamin E. The abundance of antioxidants in Hemlock Varnish Shelf has been confirmed by several other research papers. [827, 828, 829, 830]
The fungus Hemlock Varnish Shelf (Ganoderma tsugae) is common on Eastern Hemlock trees (Tsuga canadensis) throughout the Appalachian mountain range. It is the local variety of Reishi (Ganoderma spp.) in the eastern United States.
Much of the therapeutic benefits are the same as those of the Common Reishi (Ganoderma lucidum), which is the oldest used medicinal mushroom in Traditional Chinese Medicine with a 2,000 year history.
Although it can only be found in the east of the American continent, Hemlock Varnish Shelf can also be found in Southeast Asia on Asian hemlock trees. So it is not all that surprising that several Asian studies have been conducted specifically on Ganoderma tsugae.
Commercially cultivated in Taiwan and exported to mainland China as a medicinal mushroom, Hemlock Reishi has traditionally been used in Chinese medicine to treat inflammatory diseases, particularly asthma and autoimmune conditions.
The single modern study conducted on Hemlock Varnish Shelf extract to treat an autoimmune disease, conducted in 2001, concluded that it “improved the survival rate of lupus.” 
A bit more research has been conducted on asthma and lung inflammation. In 2007, it was reported that Ganoderma tsugae extract produced “anti-inflammatory effects on airway responses”  in broncheoalveolar inflammation, including allergic asthma. [802, 803]
In the annals of herbal medicine, several wood conks have been used to cauterize open wounds and speed up healing, including Agarikon (Fomitopsis officinalis) and Tinder Fungus (Fomes fomentarius). Now, modern medicine has discovered this unique application of mushrooms, and the species of choice is neither of the two mentioned above, but Hemlock Varnish Shelf. Sold as Sacchachitin, the skin substitute made from Hemlock Varnish Shelf has been said to support “rapid wound healing.”  A “wound area covered by SACCHACHITIN completely healed by 21 days, while that covered with cotton gauze did not,” concluded one study. [805, 806, 807]
Cancer research has also been conducted on Hemlock Varnish Shelf with encouraging results, [808, 809, 810, 811, 812] in particular in regards to breast  and lung cancer. [813, 814, 815] Ganoderma tsugae extract was shown in one study to be helpful in the prevention of metastatic tumors. 
Same as with Common Reishi (Ganoderma lucidum), the Hemlock Reishi (or Hemlock Varnish Shelf) has also been shown to be a powerful immunomodulator. [817, 818, 819, 820, 821, 822, 823] What that means is that both of these species of Reishi will help adjust the immune system up or down, whichever is needed. They can help strengthen a weak immune system in one person,  while helping to calm an overactive immune system in another person, perhaps someone with an autoimmune disease or an inflammatory condition such as allergy, asthma or arthritis. 
Last but not least, a 2004 study concluded that Hemlock Varnish Shelf also possessed liver protective properties as well as being anti-fibrotic. 
Note: The statements on this page have not been evaluated by the Food and Drug Administration. This article is not intended to diagnose, treat, cure or prevent any disease. Always consult a licensed medical practitioner before using any herb (or mushroom) for medicinal purposes.
Dr. Markho Rafael has worked with natural health since finishing Chiropractic College in 1996. He currently specializes in medicinal mushrooms, working specifically with the extracts from Paul Stamets, including reishi synergistic blends such as G5 (Five Ganoderma) and CordyChi . For scientific references to this article, please visit the Ganoderma tsugae list.