Lingzhi is a medicinal mushroom that has been used in traditional Chinese medicine for more than 2,000 years. Known in the West as reishi, its scientific name is Ganoderma lucidum. It belongs to the family Ganodermataceae and grows on decaying hardwood trees in temperate forests across Asia, North America, and parts of Europe. In Chinese, “lingzhi” roughly translates to “mushroom of immortality,” reflecting how highly traditional practitioners valued it for promoting longevity and overall health.
Appearance and Growth
Lingzhi is a bracket fungus, meaning it grows shelf-like from the sides of dead or dying trees rather than from the ground. The cap is kidney-shaped or fan-shaped, typically 5 to 25 centimeters across, with a glossy, lacquered surface that ranges from deep reddish-brown to nearly black. The underside is white or cream-colored and covered in tiny pores instead of the gills you’d see on a typical grocery store mushroom. The flesh is tough, woody, and bitter, which is why lingzhi has historically been consumed as a tea or decoction rather than eaten whole.
Wild lingzhi is relatively rare, but it’s now widely cultivated on logs or sawdust substrates in China, Japan, Korea, and other countries. Most lingzhi supplements on the market come from cultivated sources.
Key Active Compounds
Two groups of compounds drive most of lingzhi’s biological activity: polysaccharides and triterpenes.
Polysaccharides are long chains of sugar molecules that dissolve in water. They’re the reason lingzhi has traditionally been brewed into teas and decoctions. These compounds are primarily responsible for stimulating the immune system. They activate several types of immune cells, boost the body’s ability to engulf and destroy pathogens, and promote the release of signaling molecules that coordinate immune responses.
Triterpenes, particularly a group called ganoderic acids, are fat-soluble compounds that give lingzhi its characteristic bitter taste. In laboratory studies, ganoderic acids have shown the ability to kill or inhibit the growth of various cancer cell lines. They also appear to influence inflammation and may contribute to lingzhi’s effects on blood pressure and cholesterol.
Effects on the Immune System
The immune-boosting properties of lingzhi are its most well-documented effect. Lingzhi polysaccharides activate macrophages (cells that engulf and destroy invaders), natural killer cells (which patrol for virus-infected and cancerous cells), and T cells (which coordinate targeted immune attacks). This activation strengthens both the body’s rapid first-line defenses and its slower, more precise adaptive responses.
Beyond activating individual cell types, lingzhi promotes the production of immune signaling molecules called cytokines. Two particularly important ones are interleukin-2 and interferon-gamma, both of which help the immune system ramp up its response to threats. Lingzhi’s triterpenes contribute as well, activating signaling pathways that enhance the killing power of natural killer cells and other immune cells. The combined effect is a broad strengthening of immune surveillance, which is why lingzhi has attracted interest as a supportive therapy for people with weakened immunity.
Cardiovascular and Metabolic Effects
Several clinical trials have examined lingzhi’s effect on blood pressure and cholesterol. In a double-blind, placebo-controlled study of 160 patients with confirmed coronary heart disease, 12 weeks of treatment with lingzhi polysaccharides reduced average blood pressure from 142.5/96.4 mmHg to 135.1/92.8 mmHg. The placebo group saw no significant change. A separate trial in 38 patients with atrial fibrillation found that lingzhi polysaccharides taken three times daily for 90 days significantly reduced both systolic and diastolic blood pressure, LDL cholesterol, and several markers of inflammation.
A smaller crossover study in 26 people with borderline high blood pressure or cholesterol found only a non-significant trend toward improved triglycerides and HDL cholesterol after 12 weeks. The cardiovascular effects appear to be modest and most consistent in people who already have heart-related conditions rather than in otherwise healthy individuals.
Lingzhi and Cancer
Lingzhi is sometimes used alongside conventional cancer treatment, not as a replacement for it. A Cochrane review, the gold standard for evaluating medical evidence, examined whether lingzhi could improve outcomes for cancer patients. The review found that lingzhi may increase the chance of a positive treatment response (meaning full or partial tumor shrinkage) when used in combination with standard therapies. However, the evidence was rated very low quality, based on only two small studies involving 85 people. The reviewers noted that lingzhi appeared more promising as an add-on to chemotherapy or radiation than as a standalone treatment, but stressed that more research is needed before drawing firm conclusions.
Typical Dosage Forms
Lingzhi is available as dried powder, concentrated extracts, capsules, tinctures, and teas. The dried powder is essentially dehydrated mushroom, making it roughly ten times more concentrated than fresh lingzhi by weight. The standard dose for a basic dried extract ranges from about 1.4 to 5.2 grams per day, with 5.2 grams (split into three doses) being the most commonly studied amount.
Ethanolic extracts, which concentrate the fat-soluble triterpenes, are used at much lower doses (around 6 milligrams). Water-based extracts, which are richer in polysaccharides, are typically dosed similarly to the basic powder. Because products vary enormously in concentration and composition, the label on any specific supplement may suggest very different amounts.
Side Effects and Safety
Lingzhi is generally well tolerated. In multiple short-term placebo-controlled trials, it produced few or no adverse effects, and liver enzyme levels stayed normal throughout treatment. However, rare cases of liver injury have been reported in China, Japan, Thailand, and India. These cases typically appeared one to two months after starting lingzhi, though onset ranged from a few days to six months. Symptoms included fatigue, nausea, abdominal pain, poor appetite, dark urine, and jaundice. Most cases resolved after stopping the supplement, though a few progressed to more serious liver inflammation. The U.S. National Library of Medicine rates lingzhi as a “possible rare cause” of clinically apparent liver injury, noting that in most reported cases, other potential causes were not fully ruled out.
Drug Interactions
Lingzhi can interact with several categories of medication. It may increase bleeding risk for people taking blood thinners or antiplatelet drugs. It can amplify the blood-pressure-lowering effect of antihypertensive medications, potentially causing blood pressure to drop too low. And it may enhance the effect of diabetes medications, raising the risk of blood sugar falling below normal levels. If you take any of these types of medication, the interaction is worth discussing with a pharmacist or prescriber before starting lingzhi.