Benefits
Immune markers in a 30-person pilot trial (trend-level results)
One randomized, double-blind, placebo-controlled pilot trial tested a Phellinus linteus extract for immune support, using a lab measure of natural killer cell activity as the main outcome. It enrolled 30 people in total, 10 per group. The results were trends rather than clear differences, and the researchers wrote that the pilot secured the evidence needed to conduct the main clinical trial, which means the main trial had not been done.
What the published sanghuang trial actually showed
The published trial compared a Phellinus linteus mycelium extract (KCTC0399BP strain, 1,000 mg/day) with placebo and measured natural killer cell activity, interleukin-6 and antibody (immunoglobulin) levels. Natural killer cell activity and interleukin-6 only tended to improve, and antibody levels showed trends toward improvement, so nothing was actually established. With only 10 people per group this is preliminary. The findings also apply to one specific strain, so other Phellinus products may behave differently.
What this mushroom has not been shown to do
Phellinus linteus is often discussed alongside cancer research, but none of that work is cited on this page and none of it supports using the mushroom as a supplement for any disease. The only human study behind this page is a 30-person immune pilot. A dietary supplement cannot treat, cure or prevent cancer or any other disease, and nothing here should replace medical care.
Laboratory immune mechanism work (not human evidence)
In cell and animal studies, Phellinus linteus polysaccharides activate immune cells such as macrophages, B cells and natural killer cells, and the mushroom contains small molecules including hispolon, caffeic acid, davallialactone, interfungins A and inoscavin A. This is laboratory mechanism work only. It does not show that taking the supplement changes immune function in people.
Limits of the current human evidence
Most of what is written about this mushroom comes from cell studies, mouse studies or multi-mushroom blends rather than from people taking Phellinus linteus on its own. Animal and blend results do not carry over to a human supplement. The human record here is a single small pilot trial whose own authors said the main trial still needs to be run.
Autoimmune caution: a case report of pemphigus getting worse
There is a published case report of the skin autoimmune condition pemphigus getting worse while a person was taking Phellinus linteus. Because the mushroom is being studied for stimulating immune activity, that same activity could in theory worsen autoimmune conditions. Avoid in pemphigus, lupus, MS, RA, autoimmune thyroid conditions, and similar diagnoses.
Mulberry-tree parasitic origin (TCM heritage)
PL is selectively parasitic on mulberry trees (Morus species) — distinguishing biology from saprophytic medicinal mushrooms. That host specificity matters mainly for identifying and sourcing the mushroom. There is no human research showing it changes how the supplement works. Korean and Japanese traditional medicine emphasize the mulberry-host origin.
Mechanism of action
Polysaccharide immune cell activation
PL polysaccharides activate macrophage cytokine production, B-cell function, and NK cell cytotoxicity via pattern recognition receptor pathways (Dectin-1, TLR2/4) — standard medicinal mushroom β-glucan-type biology with PL-specific structural variants.
Hispolon and bioactive small molecules
Hispolon, caffeic acid, davallialactone, interfungins A and inoscavin A are small molecules found in Phellinus linteus that are active in laboratory models. No cited human study measured antioxidant or anti-inflammatory outcomes in people.
Cell growth signalling in laboratory models
In cell cultures, Phellinus linteus extracts change genes involved in cell growth and programmed cell death. This is early laboratory work in dishes, and it has not been tested as a health benefit in people.
Macrophage phagocytosis activation
PL extracts enhance macrophage phagocytic activity in RAW264.7 cells against yeast cells and synthetic nanoparticles — innate immune mechanism supporting the immune-function endpoints.
How cells respond in the dish
In some cell studies, certain cell lines were more sensitive to Phellinus linteus extracts than others, and only at high concentrations (above 1 mg/mL). Concentrations applied to cells in a dish do not correspond to what a supplement produces in the body, and none of this has been shown in people.
Immune signalling molecules (cytokines)
The published pilot trial measured immune signalling molecules such as interleukin-6 along with natural killer cell activity, and these only trended in the treated group. The same immune stimulation being studied is also the reason for caution in autoimmune conditions.
Clinical trials
Ku YH, Kang JH, Medicine (Baltimore) 2022. A CONSORT-reported, randomized, double-blind, placebo-controlled pilot trial of Phellinus linteus extract for immune support. 30 participants total, 10 per group.
Clinical population described in trial publication.
A randomized, double-blind, placebo-controlled pilot trial in 30 people, 10 per group. Natural killer cell activity and interleukin-6 tended to improve and antibody levels showed trends toward improvement, but none of this was established as a real effect. The authors concluded that the pilot secured the evidence needed to conduct the main clinical trial, so the definitive study has not been done.
Ku YH and colleagues, 2021 study protocol (doi:10.1186/s13063-021-05740-5). A design paper for a planned trial, with no results reported.
98 participants planned; no results published. The only published human results come from a 30-person pilot.
This 2021 paper (doi:10.1186/s13063-021-05740-5) from the same Korean team at Daejeon University College of Korean Medicine and Cheonan Korean Medicine Hospital sets out the design of a planned 98-person, 8-week trial of the mycelium extract (KCTC0399BP strain, 1,000 mg/day) measuring natural killer cell activity, cytokines and antibodies. It is a plan for a study, not results. The only published results from this program are from the 30-person pilot, whose authors wrote that the pilot secured the evidence needed to conduct the main clinical trial.
A review of laboratory and animal research on Phellinus linteus. Not a study in people.
Clinical population described in trial publication.
This is a review of laboratory research, not a clinical trial in people. It summarises how Phellinus linteus polysaccharides activate immune cells such as macrophages, B cells and natural killer cells in the lab, and lists small molecules found in the mushroom including hispolon, caffeic acid, davallialactone, interfungins A and inoscavin A. Results in cells and animals do not show what the supplement does in humans.