The short version
- A 2015 Cochrane review of reishi for cardiovascular risk factors pooled five trials in 398 participants and found no statistically or clinically significant reduction in HbA1c, total cholesterol, LDL cholesterol or body mass index.
- In that review, participants taking reishi for four months were 1.67 times more likely to report an adverse event than those on placebo, though none were serious and the estimate was imprecise.
- A 2016 Cochrane review of reishi in cancer found five randomised trials, described their methodological quality as generally unsatisfying, recorded no long-term survival data, and found insufficient evidence to justify it as a first-line treatment.
- The main study of reishi in healthy people enrolled 10 volunteers and measured antioxidant biomarkers over ten days at 0.72g a day, which is a pilot rather than evidence of any felt effect.
- No randomised placebo-controlled trial has tested reishi in healthy stressed adults with perceived stress or sleep quality as the primary outcome.
We sell reishi gummies, so read the following with that in mind and then check it yourself. Reishi — Ganoderma lucidum, lingzhi — has been consumed in Asia for a very long time and is currently sold in the West as a calming, evening, wind-down mushroom. It has been examined seriously enough to earn two Cochrane systematic reviews. Neither of them is about stress, sleep or mood.
Cochrane, twice, on other questions
Klupp and colleagues, 2015, reviewed reishi for cardiovascular risk factors. Five trials, 398 participants; three provided data usable for statistical analysis, all in people with type 2 diabetes, comparing 1.4 to 3 grams a day against placebo over 12 to 16 weeks. There was no statistically or clinically significant reduction in HbA1c (−0.10%), total cholesterol (−0.07 mmol/L), LDL cholesterol (+0.02 mmol/L) or body mass index (−0.32 kg/m²). No significant differences in blood pressure or triglycerides. Participants taking reishi for four months were 1.67 times more likely to report an adverse event than those on placebo, though none were serious, and that estimate was itself imprecise. Risk of bias was low in one of the five studies and unclear in the other four. The reviewers' conclusion was that the evidence does not support this use.
Jin and colleagues, 2016, reviewed it as a cancer treatment. Five randomised trials. Patients given reishi alongside chemotherapy or radiotherapy were more likely to respond than those on chemotherapy or radiotherapy alone (relative risk 1.50, 95% CI 0.90 to 2.51). Immune markers moved modestly: CD3 up 3.91%, CD4 up 3.05%, CD8 up 2.02%. No trial recorded long-term survival. The reviewers described the methodological quality of the primary studies as generally unsatisfying and found insufficient evidence to justify reishi as a first-line cancer treatment.
Notice what those two documents have in common. Both are careful, both are independent, and both are answering questions nobody buys a gummy for.
What exists in healthy people
Very little. The most relevant study is Wachtel-Galor and colleagues, 2004: a double-blind, placebo-controlled crossover in 10 healthy volunteers. A single 1.1g dose produced a significant rise in plasma antioxidant capacity, peaking at 90 minutes, and a 29% average rise in urine antioxidant capacity within three hours. After ten days at 0.72g a day, plasma alpha-tocopherol and urine antioxidant capacity had increased. Plasma lipids and uric acid tended to fall but not significantly. No deleterious effects were seen.
Ten people, ten days, a biomarker. That is an honest pilot and it is not a reason to feel anything. Nobody has run the trial that would matter to the person reading this: healthy adults under ordinary pressure, randomised to reishi or placebo, with perceived stress or sleep quality as the primary outcome. Compared with holy basil, which now has one properly powered eight-week stress trial, reishi's human trials in stressed people are simply absent.
The safety note we would rather you heard from us
Two case reports, published three years apart, describe liver injury after reishi in powdered form. The second, from Ramathibodi Hospital in Bangkok in 2007, was fatal fulminant hepatitis. The detail that makes both worth repeating is this: in each case the patient had previously taken traditionally boiled lingzhi without any toxic effect, and the injury followed switching to the powdered preparation for one to two months.
Two cases is not a rate, and hundreds of thousands of people take this mushroom without incident. But the preparation-specific pattern is the kind of thing that gets flattened out of a product page, and both patients were also taking other agents. If you are on prescription medication, or you have any liver history, this is a doctor conversation.
What we'd actually tell you
Our gummy is a pleasant evening ritual. That is the honest description, and rituals are not worthless — an unambiguous cue to stop working has real value, and if a chewable at nine o'clock is what closes your laptop, we are glad to sell it to you on that basis. What we are not going to do is imply it is doing pharmacology. The clinical trials that exist used grams of concentrated extract in diagnosed patients, not a confection.
If your evenings are the problem, the intervention with the better-tested numbers is free: slow breathing has more randomised data behind it than reishi does, and it is pooled across trials with actual control groups. If you want the mushroom too, take it because you like it. And do not spend energy wondering whether to cycle adaptogens like this one — with no efficacy trial in healthy adults to begin with, there is nothing for a cycling schedule to preserve.
Good questions
Does reishi actually help you relax?
No trial in healthy stressed adults has tested that, so nobody can tell you. Reishi's two Cochrane reviews cover cancer and cardiovascular risk factors, not stress or sleep. If a reishi product calms your evening, the most defensible explanation is the ritual and the expectation, and we would rather say that than invent a mechanism.
How much reishi is in a gummy compared with the studies?
A small fraction. The trials pooled by Cochrane used 1.4 to 3 grams a day of concentrated extract for 12 to 16 weeks, in people with diagnosed type 2 diabetes. A gummy delivers far less than that, in a different preparation, to a different person. Enjoy it as a ritual rather than as that trial.
Can reishi hurt your liver?
There are two published case reports of liver injury after reishi, one of them a fatal fulminant hepatitis in 2007. In both cases the patient had taken traditionally boiled lingzhi without problems and developed injury one to two months after switching to a powdered preparation, while also taking other agents. Two cases is not a rate, but it is a reason to involve your doctor if you take prescription medication.
Is reishi good for immunity?
The immune markers that moved in cancer trials moved by a few percent — CD3 up 3.91%, CD4 up 3.05%, CD8 up 2.02% — in patients undergoing chemotherapy or radiotherapy. Nobody has shown that translates into fewer colds in a healthy adult. A percentage change in a cell-surface marker is not the same claim as staying well.
Should I buy reishi at all?
Only if you want the ritual and the taste, and only with money you would not miss. We sell it, and we still think ashwagandha and slow breathing have better-tested numbers behind them for stress. If you are choosing one thing to spend on this month, reishi would not be our recommendation.
Sources
- Klupp NL, Chang D, Hawke F, et al. Ganoderma lucidum mushroom for the treatment of cardiovascular risk factors. Cochrane Database Syst Rev, 2015. View study
- Jin X, Ruiz Beguerie J, Sze DM, Chan GC. Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database Syst Rev, 2016. View study
- 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. View study
- Wanmuang H, Leopairut J, Kositchaiwat C, Wananukul W, Bunyaratvej S. Fatal fulminant hepatitis associated with Ganoderma lucidum (Lingzhi) mushroom powder. J Med Assoc Thai, 2007. View study
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.
