Reishi Mushroom

Ganoderma lucidum

Evidence Level

Limited

2 Clinical Trials

4 Documented Benefits

2/5 Evidence Score

Reishi (Ganoderma lucidum) is a revered medicinal mushroom traditionally called the mushroom of immortality, studied for immune support, stress and sleep, and general wellbeing. It is considered a calming adaptogen, with some people taking it in the evening for relaxation, and its beta-glucans and triterpenes are credited with immune and calming effects, though human sleep evidence is limited. Because reishi is too woody to eat, it is used as a hot-water or dual extract, often around 1 to 2 grams per day, standardized to beta-glucans. It is generally well tolerated, though it may have a mild blood-thinning effect and interact with immune or blood-pressure medications, so check with a doctor if relevant.

Studied Dose 1.5–9 g/day whole mushroom powder; 1–1.5 g/day standardized extract

Active Compound Beta-glucans (≥30%) and Triterpenoids (ganoderic acids) — fruiting body extract

Immune modulation

Beta-glucans from reishi activate macrophages, NK cells, and dendritic cells. The main cited human evidence is a Cochrane review (Jin 2016) of reishi as an adjunct in cancer care, which reported only low-quality evidence with some immune signal; reishi is not a cancer treatment, and this does not establish a general immune-boosting effect in healthy people.

Supported by Trial 1

Stress adaptation and sleep

Triterpenoids modulate the HPA axis and have GABA-like effects on the CNS, and are proposed to promote calm. Reishi is traditionally used as a calming adaptogen in TCM for nervous system support, but human evidence for sleep or anxiety benefits is preliminary and uncited.

Supported by Trial 2, Trial 1

Antioxidant protection

Rich in polyphenols and triterpenoids that scavenge reactive oxygen species and upregulate endogenous antioxidant enzymes (SOD, catalase, GPx), a proposed antioxidant action that is mechanistic and has not been established in human trials of reishi.

Supported by Trial 1, Trial 2

Cardiovascular support

Ganoderic acids inhibit cholesterol synthesis and platelet aggregation. These cardiovascular effects are mechanistic and uncited; reductions in blood pressure or LDL cholesterol have not been demonstrated in controlled human trials of reishi.

Supported by Trial 1, Trial 2

Beta-glucan receptor activation

Reishi beta-glucans bind to Dectin-1 receptors and TLR-2 on innate immune cells, activating NF-κB signaling and triggering production of pro-inflammatory cytokines, NK cell activation, and enhanced phagocytosis.

Triterpenoid adaptogenic activity

Ganoderic acids modulate cortisol secretion, inhibit inflammatory enzymes (COX-1/2), and interact with GABA-A receptors to produce calming and sleep-promoting effects.

HMG-CoA reductase inhibition

Certain ganoderic acids inhibit HMG-CoA reductase, the rate-limiting enzyme in cholesterol biosynthesis — same target as statin drugs — a proposed mechanism; lipid-lowering effects of reishi have not been established in human trials.

Reishi for Immune Function in Advanced Cancer — Clinical Trial

Study info

Clinical trial of reishi (Ganoderma lucidum) polysaccharide extract vs placebo in 48 advanced colorectal cancer patients over 12 weeks. Outcomes: NK cell activity, lymphocyte counts, cytokines.

Population & duration

48 advanced colorectal cancer patients.

Findings

Reishi modestly increased NK cell counts and lymphocyte populations vs placebo. Critical context: cancer patients should never replace evidence-based oncology with reishi; immune-modulating supplements during active treatment should be coordinated with oncologist. Some immune supplements may interact with chemotherapy/immunotherapy. Reishi is at most adjunctive in supportive care.

Reishi for QoL in Breast Cancer — Clinical Trial

Study info

Clinical trial examining reishi extract supplementation in breast cancer patients undergoing endocrine therapy.

Population & duration

Breast cancer patients.

Findings

Modest improvements in fatigue, anxiety, QoL scores; higher NK cell activity vs control. Note: same caveat — coordinate with oncology team.

Common Potential side effects

GI upset, dry mouth, dizziness in some users especially at higher doses

Mild liver enzyme elevation reported with long-term use of concentrated extracts — monitor

Potential allergic reactions in mushroom-sensitive individuals

Important Drug interactions

Anticoagulants (warfarin) — reishi inhibits platelet aggregation; increased bleeding risk

Antihypertensives — additive blood pressure-lowering effect

Immunosuppressants — reishi stimulates immune function; may counteract cyclosporine

Frequently asked questions about Reishi Mushroom

What is reishi mushroom used for?

Reishi (Ganoderma lucidum) is a revered medicinal mushroom studied for immune support, stress and sleep (it is considered calming), and general wellbeing. It is traditionally called the mushroom of immortality in East Asian medicine.

Does reishi help with sleep and stress?

Reishi is traditionally used as a calming adaptogen, and some take it in the evening for relaxation and sleep support. Its beta-glucans and triterpenes are credited with immune and calming effects, though human sleep evidence is limited.

How much reishi should I take?

Doses depend on the extract, commonly around 1 to 2 grams of extract per day; follow product labeling. Hot-water or dual extracts standardized to beta-glucans (and triterpenes) are preferred, since reishi is too woody to eat.

Is reishi safe?

Reishi is generally well tolerated; occasional digestive upset or dry mouth can occur. It may have a mild blood-thinning effect and interact with immune or blood-pressure medications, so check with your doctor if relevant.

What is Reishi Mushroom?

Reishi (Ganoderma lucidum) is a revered medicinal mushroom traditionally called the mushroom of immortality, studied for immune support, stress and sleep, and general wellbeing.

What is the recommended dosage of Reishi Mushroom?

The clinically studied dose is 1.5–9 g/day whole mushroom powder; 1–1.5 g/day standardized extract Always follow the product label and check with a healthcare provider for personal advice.

Is Reishi Mushroom safe, and does it have side effects?

For most healthy adults, Reishi Mushroom is well tolerated at studied doses. Reported effects can include: GI upset, dry mouth, dizziness in some users especially at higher doses Mild liver enzyme elevation reported with long-term use of concentrated extracts — monitor It may also interact with some medications. Reishi Mushroom is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Reishi Mushroom interact with any medications?

Possible interactions include: Anticoagulants (warfarin) — reishi inhibits platelet aggregation; increased bleeding risk Antihypertensives — additive blood pressure-lowering effect If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Reishi Mushroom?

NutraSmarts rates the evidence for Reishi Mushroom as Limited (2 out of 5). It is backed by 2 clinical trials and 1 cited reference summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(1 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

Jin X, Ruiz Beguerie J, Sze DM, Chan GC. Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database Syst Rev. 2016;4(4):CD007731..PubMedUsed to support: Cochrane review reporting immune-modulating and adjunct effects of reishi (Ganoderma lucidum) in cancer care.

Reishi Mushroom

Benefits

Immune modulation

Stress adaptation and sleep

Antioxidant protection

Cardiovascular support

Mechanism of action

Beta-glucan receptor activation1

Triterpenoid adaptogenic activity1

HMG-CoA reductase inhibition2

Clinical trials

Side effects and drug interactions