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Ingredient guide

Reishi mushroom benefits: what the research shows

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

Reishi is a bitter, woody mushroom from traditional Chinese medicine. In small trials of healthy adults, whole reishi at 1.44 to 4 g a day left blood and immune markers largely unchanged, while one company-funded trial of a purified extract found more immune cells. LiverTox says no claimed benefit has been shown in proper trials.1,2,3,4

Key facts

  • LiverTox gives the usual amount of reishi as 500 mg to 3 g a day.4
  • A 2025 review of 17 randomized trials rated the certainty of every reishi finding as very low.5
  • Only 5 of 19 reishi supplements bought in the United States matched their labels when tested.6
  • Liver injury linked to reishi is rare, and LiverTox rates it a possible rare cause.4

What reishi is

Reishi is a large, reddish-brown mushroom with a fan-shaped cap that grows at the base of trees or on stumps. Because it is rare in the wild, it is cultivated on logs, sawdust or wood chips.4

It is called lingzhi in China and reishi in Japan, and labels may list it as Ganoderma lucidum or Ganoderma lingzhi.4

Its main use has been in traditional Chinese medicine, where it was prized as a tonic for vitality and a long life. In Western countries it is now sold mostly as an extract, alone or in blends that make claims about energy and concentration.4

Reishi contains polysaccharides, triterpenoids, sterols, fatty acids, proteins and trace elements. Which of them, if any, act in the body is unknown.4

Two groups of compounds get the most attention. Beta-glucans are long chains of sugars that immune cells can recognize. Ganoderic acids are the bitter triterpenes, and the gut absorbs them within minutes.3,7

What the evidence shows

Each claim on this page carries a grade for how much human research there is and how well it agrees, not for how large the effect is. For reishi, one finding in healthy people passes our evidence rules, and it is graded early. Many reishi trials enrolled people under medical care, and their results are not used here.

A purified reishi beta-glucan may raise counts of some immune cells in healthy adults*1,2,3,8

Early evidence

In a randomized, placebo-controlled trial in healthy adults aged 18 to 55 (157 enrolled, 135 finished), 200 mg a day of a purified reishi beta-glucan for 12 weeks raised counts of several kinds of T cells and natural killer cells more than placebo. It did not measure whether people fell ill less often, and a company paid for it. A trial in young children who ate a yogurt with reishi beta-glucans found a similar rise. Whole reishi did not show this: 1.44 g a day for 4 weeks, and 4 g a day of an extract for 10 days, left immune measures unchanged in small trials.

Amount studied: 200 mg a day of purified reishi beta-glucan, for 12 weeks

LiverTox notes that none of reishi's claimed benefits has been demonstrated in adequately sized, properly controlled human trials.4

A 2025 pooled analysis of 17 randomized trials in 971 people rated the certainty of every reishi finding as very low.5

After a single 1.1 g dose, antioxidant capacity in blood plasma rose briefly and peaked at about 90 minutes. Four weeks at 1.44 g a day changed no blood marker of antioxidant status, although antioxidant capacity in urine rose.1,9

Antioxidant readings in blood are not a measure of health on their own, and these results disagree with each other. We also found no trial in healthy adults that measured reishi's effect on sleep, energy or concentration.1,9

How much people take

LiverTox gives the usual amount of reishi as 500 mg to 3 g a day.4

Trials in healthy adults gave 0.72 to 4 g a day of whole reishi preparations or extracts, for 10 days to 4 weeks.1,2,9,10

Grams are hard to compare between products. A dried preparation, a water extract and a purified beta-glucan are different things, and the 1.44 g a day used in one trial was the equivalent of 13.2 g of fresh mushroom. The dosage guide lists the amount used in each trial.1

Forms and quality

Reishi is sold as an extract on its own or in blends with other herbs, and as powders, dried slices and spore powder.4

A purified reishi beta-glucan concentrates one group of compounds. The rise in immune cells seen with it did not appear in small trials of whole reishi at 1.44 to 4 g a day.1,2,3

When 19 reishi supplements bought in the United States were analyzed, the measured triterpenes and polysaccharides matched the label in only 5.6

Reishi has a distinctly bitter taste. It is used in cooking and to make herbal tea, but its main use has been in traditional Chinese medicine.4

What's in ours

Our Mushroom Complex lists reishi extract made from the fruiting body. Its label gives no beta-glucan figure, so the graded immune finding above, which used a purified beta-glucan at 200 mg a day, does not apply to it. Its reishi amount also sits below the 500 mg low end of the usual range.3,4

Side effects, medicines and who should ask first

Small, short trials have reported few or no side effects, and there is little information on common side effects in people.2,4

Rare cases of liver injury have been reported, usually 1 to 2 months after starting reishi, with tiredness, nausea, stomach pain, poor appetite, dark urine or yellowing of the skin and eyes. Most people recovered within 1 to 3 months of stopping, but one woman died.4

In two of the reported liver cases, the trouble began after the person switched to a powdered reishi product.4

No upper limit has been set for reishi. Trials have used 200 mg to 11.2 g a day for 1 to 24 weeks, so longer use has not been tested.5

Laboratory studies once suggested reishi could slow platelets, but in a trial of 40 healthy volunteers clotting tests did not change. If you take warfarin, its label asks for more frequent INR checks whenever an herbal product is started or stopped.10,11

  • Ask your doctor first if you have liver disease, and stop reishi if you notice dark urine, yellowing of the skin or eyes, or unusual tiredness4
  • Ask first if you take a blood thinner or have surgery planned
  • Ask first if you take medicine for blood sugar or blood pressure: lab and animal studies suggest reishi may lower both, although trials in people have not shown it4,12
  • Ask first if you take medicines that suppress the immune system
  • Ask first if you are under cancer care: reishi is popular with people having cancer treatment and has been used alongside chemotherapy4,10
  • Ask first if you are pregnant or breastfeeding

The official sources we use name no specific medicine that interacts with reishi. That is not proof that any combination is free of risk, so tell your pharmacist about reishi before taking it alongside a prescription.

Questions people ask

Does reishi help with sleep?

There is no good evidence either way. We found no trial in healthy adults that measured reishi's effect on sleep, and LiverTox notes that none of reishi's claimed benefits has been shown in adequately sized, properly controlled human trials.4

Are reishi and lingzhi the same thing?

Yes. Lingzhi is the Chinese name and reishi the Japanese name for the same mushroom. Labels may list it as Ganoderma lucidum or Ganoderma lingzhi.4

Are there reishi benefits for men in particular?

We found no study of reishi benefits in men in particular. The one study we read that enrolled only men, an absorption study in 12 men, measured how fast reishi compounds reach the blood rather than any benefit.7

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Sources

  1. Wachtel-Galor S, Tomlinson B, Benzie IF. Ganoderma lucidum ("Lingzhi"), a Chinese medicinal mushroom: biomarker responses in a controlled human supplementation study. Br J Nutr. 2004;91(2):263-269. Opened 2026-10-07.
  2. Wicks SM, Tong R, Wang CZ, O'Connor M, Karrison T, Li S, Moss J, Yuan CS. Safety and tolerability of Ganoderma lucidum in healthy subjects: a double-blind randomized placebo-controlled trial. Am J Chin Med. 2007;35(3):407-414. Opened 2026-10-07.
  3. Chen SN, Nan FH, Liu MW, Yang MF, Chang YC, Chen S. Evaluation of Immune Modulation by β-1,3; 1,6 D-Glucan Derived from Ganoderma lucidum in Healthy Adult Volunteers, A Randomized Controlled Trial. Foods. 2023;12(3):659. Opened 2026-10-07.
  4. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Lingzhi, Reishi. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases. Last update October 5, 2024. Opened 2026-10-07.
  5. Jafari A, Mardani H, Mirzaei Fashtali Z, Arghavan B. The Nutritional Significance of Ganoderma lucidum on Human Health: A GRADE-Assessed Systematic Review and Meta-Analysis of Clinical Trials. Food Sci Nutr. 2025;13(6):e70423. Opened 2026-10-07.
  6. Wu DT, Deng Y, Chen LX, Zhao J, Bzhelyansky A, Li SP. Evaluation on quality consistency of Ganoderma lucidum dietary supplements collected in the United States. Sci Rep. 2017;7(1):7792. Opened 2026-10-07.
  7. Teekachunhatean S, Sadja S, Ampasavate C, Chiranthanut N, Rojanasthien N, Sangdee C. Pharmacokinetics of ganoderic acids A and F after oral administration of Ling Zhi preparation in healthy male volunteers. Evid Based Complement Alternat Med. 2012;2012:780892. Opened 2026-10-07.
  8. Henao SLD, Urrego SA, Cano AM, Higuita EA. Randomized Clinical Trial for the Evaluation of Immune Modulation by Yogurt Enriched with β-Glucans from Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Agaricomycetes), in Children from Medellin, Colombia. Int J Med Mushrooms. 2018;20(8):705-716. Opened 2026-10-07.
  9. Wachtel-Galor S, Szeto YT, Tomlinson B, Benzie IF. Ganoderma lucidum ('Lingzhi'); acute and short-term biomarker response to supplementation. Int J Food Sci Nutr. 2004;55(1):75-83. Opened 2026-10-07.
  10. Kwok Y, Ng KFJ, Li CCF, Lam CCK, Man RYK. A prospective, randomized, double-blind, placebo-controlled study of the platelet and global hemostatic effects of Ganoderma lucidum (Ling-Zhi) in healthy volunteers. Anesth Analg. 2005;101(2):423-426. Opened 2026-10-07.
  11. Warfarin sodium tablets: prescribing information (A-S Medication Solutions). DailyMed, U.S. National Library of Medicine. Published September 23, 2026. Opened 2026-10-07.
  12. Klupp NL, Chang D, Hawke F, Kiat H, Cao H, Grant SJ, Bensoussan A. Ganoderma lucidum mushroom for the treatment of cardiovascular risk factors. Cochrane Database Syst Rev. 2015;(2):CD007259. Opened 2026-10-07.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.