Reishi mushroom, what it is, what trials found and safety
Where reishi grows, why tested products were mostly lingzhi, what trials in people found, the doses they used and what to know about side effects and the liver.
- Written by
- Liz W.
- Last updated
- Reading time
- 7 min read
Overview
Reishi is a shiny Ganoderma mushroom used in Asia for over 2,000 years, and most products in a DNA study were lingzhi. Small trials found less fatigue and better well-being scores, but a review of 5 trials found no effect on blood sugar, blood pressure or blood fats. Rare cases of liver injury have been reported.
Key points
- In DNA tests of 20 reishi products, 93% were lingzhi, an Asian species, and none held true Ganoderma lucidum.
- In 132 adults with long-lasting fatigue, more people improved on a reishi extract than on placebo.
- A review of 17 trials found small drops in heart rate and body mass index, with very low certainty.
- Reishi didn't change blood sugar, blood pressure or blood fats in a review of 5 trials.
- Liver injury is rare, and reishi can raise bleeding risk with blood thinners such as warfarin.
Reishi has a glossy, varnished-looking cap, and the name Ganoderma lucidum has been used for most shiny mushrooms of its kind. The true species has a small native range in Europe and parts of China. When a US team ran DNA tests on 20 reishi products, none of them contained it. Most held lingzhi (Ganoderma lingzhi), an Asian cousin and the species most widely grown and studied [1].
Reishi has been used in Asia for over 2,000 years [1], and today it's sold as capsules, powders, teas and extracts. Small trials found less fatigue and better well-being scores, while a review of 5 trials found no effect on blood sugar, blood pressure or blood fats [2][3][4]. It's usually well tolerated, though rare cases of liver injury have been reported [5].
What is reishi mushroom?
Reishi and lingzhi are names for the same group of shiny Ganoderma mushrooms. Lingzhi is native to Asia and is the one grown on a large scale, which is why it turned up in most of the products in that DNA study [1].
So the label says Ganoderma lucidum. The DNA test usually says lingzhi.
Products are made from the fruiting body, the mushroom you can see, or from the mycelium, its network of root-like threads. Our guide to functional mushrooms explains what that difference means on a label.
What is reishi mushroom good for?
Reishi has been tested for fatigue, fitness, mood and heart health, and alongside cancer treatment. The positive results come from small trials, as the table shows.
| Area | What trials found | Evidence |
|---|---|---|
| Fatigue | More of 132 adults with long-lasting fatigue improved on an extract over 8 weeks than on placebo [2] | Early |
| Fitness and well-being | Fitter than on placebo, with better anxiety and well-being scores, at 1,000 mg a day in 78 inactive young women over 30 days [3] | Early |
| Immune cells | Changes in lab tests of immune cells, in 39 older women after 8 weeks [6] | Early |
| Blood sugar, blood pressure and blood fats | No effect across 5 trials of 398 people, mostly with type 2 diabetes [4] | Mixed |
| Alongside cancer treatment | Tumours responded more often with chemotherapy or radiotherapy in 5 trials, but the effect on survival was unclear [7] | Early |
A 2025 review pooled 17 trials with 971 people. Reishi brought small drops in body mass index and heart rate, but no change in blood pressure, blood sugar, blood fats, inflammation or liver enzymes. The authors rated the certainty of every result as very low [8].
The fatigue trial was in people in China diagnosed with neurasthenia, a long-lasting fatigue condition, and it used a high-dose extract [2]. The immune trial measured immune cells in blood samples, not how often people got ill [6].
Reishi isn't a treatment for cancer. A Cochrane review found too little evidence to use it as a first treatment [7], so speak to your cancer team before taking it alongside chemotherapy [5].
So the encouraging results come from short, small trials, and the longer heart health trials found little.
Does reishi help you sleep?
We found no trial in people that tested reishi alone for sleep, and the studies we found on reishi and sleep were in animals. Trouble sleeping is even listed among its reported side effects [5].
If sleep is your aim, our guide to natural sleep aids compares the options that have been tested in people.
How much reishi do trials use?
Doses vary widely. Across 17 trials, people took 200 mg to 11,200 mg a day for 1 to 24 weeks [8]. The heart health trials used 1.4 to 3 g a day for 12 to 16 weeks [4], and the fatigue trial used 1,800 mg of extract three times a day [2].
Extracts and dried mushroom powder are made differently, so check whether a label gives the amount of extract or of mushroom. Reishi coffee blends are covered in our guide to mushroom coffee.
Is reishi safe?
Reishi is usually well tolerated in trials. In a 16-week trial of 3 g a day, side effects were no more common than on placebo [9]. A review of 5 trials found more minor side effects than placebo, none of them serious [4].
Reported side effects include nausea, dry mouth, constipation, itching, dizziness and trouble sleeping [5].
Liver injury is rare but serious. One person died after taking reishi powder [5]. A man who drank large amounts of vodka while taking spoonfuls of reishi powder developed liver injury, which cleared within two weeks once he stopped both [10]. Stop taking it and see a GP if you feel unwell.
Reishi can raise the risk of bleeding if you take blood thinners such as warfarin, and it may not be safe with medicines that dampen the immune system [5]. If you take any medicine, or you're pregnant or breastfeeding, check with your GP or pharmacist before trying it.
Frequently asked questions
Is reishi the same as lingzhi?
The names are used for the same group of shiny Ganoderma mushrooms. In DNA tests of 20 products labelled Ganoderma lucidum, 93% were lingzhi [1].
What does reishi mushroom do?
Small trials found less fatigue and better well-being scores, but a review of 17 trials rated the certainty of every result as very low [2][8].
Is reishi good for anxiety and stress?
In one 30-day trial of 78 young women, anxiety and well-being scores improved on 1,000 mg a day [3]. That's a single small trial.
Does reishi lower blood pressure?
Reviews found no effect on blood pressure, across 5 trials in one review and 17 in another [4][8].
Is reishi bad for your liver?
Liver injury is rare, but cases have been reported with reishi powder, including one death [5][10].
How much reishi should you take a day?
Trials used anything from 200 mg to 11,200 mg a day [8]. Follow the label, and check whether it gives the amount of extract or of dried mushroom.
Read more about other mushrooms in our guide to functional mushrooms.
References
Every source here is listed so you can read it yourself. This guide is for general information and doesn't replace advice from your GP. We check it again at least every six months.
- Loyd AL, Richter BS, Jusino MA, Truong C, Smith ME, Blanchette RA et al. (2018). Identifying the "Mushroom of Immortality": Assessing the Ganoderma Species Composition in Commercial Reishi Products. Frontiers in Microbiology 9: 1557. PMID 30061872
- Tang W, Gao Y, Chen G, Gao H, Dai X, Ye J et al. (2005). A randomized, double-blind and placebo-controlled study of a Ganoderma lucidum polysaccharide extract in neurasthenia. Journal of Medicinal Food 8(1): 53-58. PMID 15857210
- Mitra S, Mitra M, Nandi DK, Saha M, Bandyopadhyay A (2024). Efficacy of Lingzhi or Reishi Medicinal Mushroom Ganoderma lucidum Supplementation on Psychological Stress and Selective Fitness Profile Parameters in Female College Students in West Bengal, India. International Journal of Medicinal Mushrooms 26(11): 51-64. PMID 39241163
- Klupp NL, Chang D, Hawke F, Kiat H, Cao H, Grant SJ et al. (2015). Ganoderma lucidum mushroom for the treatment of cardiovascular risk factors. Cochrane Database of Systematic Reviews (2): CD007259. PMID 25686270
- Memorial Sloan Kettering Cancer Center. About Herbs: Reishi Mushroom. Last updated 5 May 2026. Accessed 30 October 2026. mskcc.org
- Iser-Bem PN, Lobato TB, Alecrim-Zeza AL, Dos Santos de Oliveira LC, Passos MEP, Manuel R et al. (2024). Ganoderma lucidum dry extract supplementation modulates T lymphocyte function in older women. British Journal of Nutrition 132(2): 130-140. PMID 38800991
- Jin X, Ruiz Beguerie J, Sze DM, Chan GC (2016). Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database of Systematic Reviews 4: CD007731. PMID 27045603
- Jafari A, Mardani H, Mirzaei Fashtali Z, Arghavan B (2025). The Nutritional Significance of Ganoderma lucidum on Human Health: A GRADE-Assessed Systematic Review and Meta-Analysis of Clinical Trials. Food Science & Nutrition 13(6): e70423. PMID 40510787
- Klupp NL, Kiat H, Bensoussan A, Steiner GZ, Chang DH (2016). A double-blind, randomised, placebo-controlled trial of Ganoderma lucidum for the treatment of cardiovascular risk factors of metabolic syndrome. Scientific Reports 6: 29540. PMID 27511742
- Guedikian R, Kim B, Singh G, Alexander R (2023). Ganoderma lingzhi (Reishi Mushroom)-Induced Acute Liver Injury in the Setting of Alcohol Use: A Case Report and Literature Review. Cureus 15(9): e45953. PMID 37885515
