Life Extension Magazine®

Woman stretching before running with reishi mushrooms to the side

Reishi Mushrooms Prevent Obesity in Mice

A new study in overweight mice has found that Reishi mushrooms can reduce body weight and prevent weight gain and fat accumulation by acting as a unique prebiotic. While this has not yet been tested in humans, the benefits are intriguing and show potential in the fight against obesity.

Scientifically reviewed by: Holli Ryan, RD, LD/N, in August 2023. Written by: Brian Ross.

Obesity and persistent weight gain are caused by a host of complex factors.

Researchers are extensively exploring the role the bacteria in our gut (our microbiome) have on health and disease.

A new lab study has found preliminary data that Reishi mushrooms and their extracts, long known for their immune benefits, can reduce body weight and prevent weight gain and fat accumulation in an unexpected way in mice fed a high-fat diet. While this is preliminary data, not tested in humans, the mechanism of action and the benefits are intriguing and show potential. Over time, Life Extension® will keep you informed of more developments and research with regard to Reishi mushrooms.

What has been discovered is the Reishi mushrooms act as a unique prebiotic to favorably change the composition of the intestinal microbial community in a way that favors biological weight reduction.1

What the New Study Showed

An international group of scientists has published a report of the effects of Reishi mushrooms (Ganoderma lucidum) on body weight and obesity-related disorders.1

Using a mouse model of obesity for their study, the researchers found that the mice fed a high-fat diet alone for 8 weeks had a significant increase in body and liver weight, as well as in the size of fat deposits within the body. Furthermore, the obese mice showed increased deposition of fat inside liver and fat cells, just as it is seen in obese humans.

A second group of mice was started on the high-fat diet at the same time, but received, in addition, supplementation with an extract from Reishi mushrooms at varying concentrations. Both of these mouse groups became obese in response to this high-fat diet.

Compared to the non-supplemented group, the mice supplemented with Reishi mushrooms showed:1

  • A decrease in body weight of approximately 8% to 16%.
  • Decreases in the fat deposited within the body cavity of about 20% to 29%.
  • Decreases in the fat deposited beneath the skin of approximately 44% to 59%.
  • A decrease in liver weight, the site of abnormal fat deposition that leads to fatty liver disease, of about 17%.
  • Reduction in the size and fat content of adipocytes, the cells that produce and store fat.

In addition to these reductions in weight and fat distributions, this study identified significant reductions in markers of inflammation.1 This is not surprising, given that fat cells pour out inflammatory signaling molecules (cytokines).

The reduction in pro-inflammatory cytokine production was more pronounced at higher mushroom doses. The supplemented mice also showed significant reductions in the activity of a potent inflammation inducer called nuclear factor-kappa B (NFkB).

Furthermore, supplemented animals showed significant reductions in amounts of bacterial toxins in their bloodstreams, compared with obese, high-fat fed mice.1 This is critical, because overfed obese animals (and humans) develop “leaky guts,” allowing intestinal bacterial products to enter the bloodstream, where they trigger both inflammation and insulin resistance, which leads to diabetes.2

Finally, further molecular evidence of how the mushroom supplement reduced weight gain and body weight was demonstrated by the finding of reduction in the expression of genes involved in fat production.1 This led to a reduction in fat concentrations in the blood of the supplemented animals.

Previous Studies Offered Hints of Reishi’s Metabolic Benefits

Previous Studies Offered Hints of Reishi’s Metabolic Benefits  

Reishi mushrooms have been used for hundreds of years to promote good health and long life.1,3 And, although this is the first-ever proof of Reishi mushrooms’ direct effects on body weight and fat distribution, there had been previous hints that these time-honored fungi could favorably influence fat and sugar metabolism.

Reishi extracts are rich in compounds called triterpenes and polysaccharides, which have been shown to inhibit full development of fat cells, and to lower blood sugar in diabetic animals.1,4,5 And other studies have shown that different compounds from Reishi can produce blood fat- and glucose-lowering effects, while providing free radical scavenging activity.1,6

An entirely separate line of research, meanwhile, has demonstrated that the trillions of microorganisms living in our intestinal tract may have an impact on obesity and other metabolic disorders such as diabetes and metabolic syndrome.1,7 These organisms, formerly thought to be just “along for the ride,” are now recognized to contribute importantly to the ways our bodies acquire nutrients and regulate energy.1,8,9

In particular, the composition of our internal bacterial communities seems to influence our metabolic status. Changes in the percentage of gut bacteria’s individual species, as well as in their ratios to each other, have been shown to promote, or oppose, the development of obesity in animals.1,10,11

Furthermore, an imbalance of the gut organism community can damage the intestinal lining in such a way that it leaks, permitting inflammation-promoting compounds to enter the bloodstream, which ultimately produces body-wide inflammation and insulin resistance, triggering further risk of obesity and metabolic derangements.1,2,12-15

At this point it is natural to ask: if imbalanced gut microbial communities can cause metabolic disturbances leading to obesity, can restoring that balance restore metabolic equilibrium?

There is now evidence that this is indeed the case. Studies show that antibiotics aimed at specific organisms can reduce leakage of inflammatory materials from the intestine into the bloodstream in obese mice.1,12

But antibiotics bring with them a host of problems, including not only immediate side effects, but also long-term risks of drug-resistant organisms, and no one is seriously proposing widespread antibiotics as a cure for obesity.

Importance of Prebiotics

Importance of Prebiotics  

A more natural way to change the composition of the gut microbial community is to change what it eats.

Prebiotics are fermentable fiber and carbohydrate molecules that nourish specific bacterial groups in the intestine, helping to restore a natural balance.

Prebiotic treatment has been shown to reduce body weight and inflammation by boosting communities of beneficial organisms, which in turn may help suppress less beneficial groups.1,16,17 Furthermore, prebiotic treatment can enhance the “tightness” of the intestinal wall, preventing leakage of inflammatory material into the circulation.2

The scientists who carried out the study reported here wondered, then, whether the beneficial effects they were seeing on body weight and fat distribution might arise from some prebiotic properties of Reishi mushrooms. To answer that question, they examined the composition of their animals’ intestinal microbial communities.

Reishi Mushrooms Offer Prebiotic Support

In response to Reishi, humans and obese mice showed a serious alteration in their intestinal microbial community. What researchers found was that both obese mice and humans had an elevated population of inflammation-promoting microbes with a decrease in anti-inflammatory microbes.1,18,19

When the scientists examined the microbial population of the mice’s intestines, they found that the obese, high-fat-fed mice had the expected patterns of intestinal microbial imbalance associated with obesity.1 But when the obese mice were supplemented with Reishi mushrooms, the mice displayed a more “normal” and less inflammatory microbial pattern. When the mice were fed the two higher doses of Reishi mushrooms, it restored the obese mice’s microbial patterns to levels similar to control mice.

In other words, Reishi supplementation had a prebiotic effect, feeding beneficial organisms at the expense of deleterious ones, and triggering a chain of events beginning with normalization of the microbial community, and leading to reduction of inflammation, tightening of leaky intestinal walls, reduced insulin resistance, diminished fat production, and ultimately to the observed weight reduction compared with unsupplemented mice.

Human Studies Needed


Human Studies Needed

The weight control benefits for Reishi have only been demonstrated in laboratory mammals. We hope this Research Update spurs human studies to ascertain the ideal dose of Reishi to assist humans in preventing age-associated weight gain.



Reishi mushrooms and their polysaccharide extracts were shown to produce powerful prebiotic effects in obese, high-fat-fed mice, which led to distinctive changes in their intestinal microbial communities.

Those changes, in turn, set off a beneficial chain reaction resulting in reduced body weight, slower weight gain, improved fat deposition in the body, and a host of beneficial biochemical changes associated with optimized metabolic health.

Given that human intestinal microbes exert similar control over metabolism and weight, there is reason to investigate whether similar results from oral supplementation with Reishi mushroom extracts will manifest in people.

If you have any questions on the scientific content of this article, please call a Life Extension® Wellness Specialist at 1-866-864-3027.


  • Chang CJ, Lin CS, Lu CC, et al. Ganoderma lucidum reduces obesity in mice by modulating the composition of the gut microbiota. Nat Commun. 2015;6:7489.
  • Cani PD, Possemiers S, Van de Wiele T, et al. Changes in gut microbiota control inflammation in obese mice through a mechanism involving GLP-2-driven improvement of gut permeability. Gut. 2009;58(8):1091-103.
  • Sanodiya BS, Thakur GS, Baghel RK, et al. Ganoderma lucidum: a potent pharmacological macrofungus. Curr Pharm Biotechnol. 2009;10(8):717-42.
  • Thyagarajan-Sahu A, Lane B, Sliva D. ReishiMax, mushroom based dietary supplement, inhibits adipocyte differentiation, stimulates glucose uptake and activates AMPK. BMC Complement Altern Med. 2011;11:74.
  • Li F, Zhang Y, Zhong Z. Antihyperglycemic effect of ganoderma lucidum polysaccharides on streptozotocin-induced diabetic mice. Int J Mol Sci. 2011;12(9):6135-45.
  • Pan D, Zhang D, Wu J, et al. Antidiabetic, antihyperlipidemic and antioxidant activities of a novel proteoglycan from ganoderma lucidum fruiting bodies on db/db mice and the possible mechanism. PLoS One. 2013;8(7):e68332.
  • Ridaura VK, Faith JJ, Rey FE, et al. Gut microbiota from twins discordant for obesity modulate metabolism in mice. Science. 2013;341(6150):1241214.
  • Dethlefsen L, McFall-Ngai M, Relman DA. An ecological and evolutionary perspective on human-microbe mutualism and disease. Nature. 2007;449(7164):811-8.
  • Backhed F, Ding H, Wang T, et al. The gut microbiota as an environmental factor that regulates fat storage. Proc Natl Acad Sci U S A. 2004;101(44):15718-23.
  • Turnbaugh PJ, Ley RE, Mahowald MA, et al. An obesity-associated gut microbiome with increased capacity for energy harvest. Nature. 2006;444(7122):1027-31.
  • Goodman AL, Kallstrom G, Faith JJ, et al. Extensive personal human gut microbiota culture collections characterized and manipulated in gnotobiotic mice. Proc Natl Acad Sci U S A. 2011;108(15):6252-7.
  • Cani PD, Bibiloni R, Knauf C, et al. Changes in gut microbiota control metabolic endotoxemia-induced inflammation in high-fat diet-induced obesity and diabetes in mice. Diabetes. 2008;57(6):1470-81.
  • Cani PD, Amar J, Iglesias MA, et al. Metabolic endotoxemia initiates obesity and insulin resistance. Diabetes. 2007;56(7): 1761-72.
  • Wellen KE, Hotamisligil GS. Inflammation, stress, and diabetes. J Clin Invest. 2005;115(5):1111-9.
  • Shi H, Kokoeva MV, Inouye K, et al. TLR4 links innate immunity and fatty acid-induced insulin resistance. J Clin Invest. 2006;116(11):3015-25.
  • Nakamura YK, Omaye ST. Metabolic diseases and pro- and prebiotics: Mechanistic insights. Nutr Metab (Lond). 2012;9(1):60.
  • Everard A, Lazarevic V, Derrien M, et al. Responses of gut microbiota and glucose and lipid metabolism to prebiotics in genetic obese and diet-induced leptin-resistant mice. Diabetes. 2011;60(11): 2775-86.
  • Brun P, Castagliuolo I, Di Leo V, et al. Increased intestinal permeability in obese mice: new evidence in the pathogenesis of nonalcoholic steatohepatitis. Am J Physiol Gastrointest Liver Physiol. 2007;292(2):G518-25.
  • Ley RE, Turnbaugh PJ, Klein S, et al. Microbial ecology: human gut microbes associated with obesity. Nature. 2006;444(7122):1022-3.