Reishi mushroom (Ganoderma lucidum) is a fungus widely recognized in traditional East Asian medicine. Used for centuries, this mushroom is valued for its adaptogenic properties, helping the body maintain balance and adapt to stress. As interest in natural supplements grows, questions have arisen about how Reishi interacts with the endocrine system, specifically its potential influence on male hormones. Concerns often center on whether this fungus can reduce testosterone levels, requiring a closer look at the biological mechanisms and existing scientific evidence.
How Reishi Might Influence Androgen Levels
The theoretical basis for Reishi’s effect on male hormones involves its interaction with an enzyme called 5-alpha reductase (5-AR). This enzyme is responsible for converting testosterone into a more potent androgen, dihydrotestosterone (DHT). Certain compounds within the Reishi mushroom are believed to interfere with this conversion process.
The primary bioactive compounds implicated in this mechanism are fatty molecules known as triterpenoids, specifically ganoderols B and F. These triterpenoids inhibit the activity of the 5-AR enzyme. By blocking 5-AR, Reishi theoretically limits the amount of DHT produced from circulating testosterone. This anti-androgenic effect is often studied in the context of conditions driven by high DHT levels, such as benign prostatic hyperplasia (BPH).
Beyond inhibiting 5-AR, some Reishi compounds may also interfere with the androgen receptor itself. Research indicates that certain triterpenoids can prevent testosterone and DHT from binding to these receptor sites. This dual mechanism—reducing DHT production and blocking androgen action—gives Reishi its potent anti-androgenic reputation in laboratory settings.
What Clinical Studies Show About Testosterone Levels
The strong anti-androgenic effects observed in laboratory and animal models do not always translate directly to changes in human serum testosterone. In test-tube studies, Reishi extracts (especially those using alcohol) have shown significant 5-AR inhibition, sometimes rivaling pharmaceutical inhibitors. Animal studies confirm that Reishi can suppress the testosterone-induced growth of the prostate in castrated rats, indicating a clear biological effect on androgen-dependent tissues.
However, when measuring circulating testosterone in healthy human subjects, the results are notably different. Studies involving human participants, including older men, have generally shown little to no significant change in total serum testosterone or free testosterone levels. For example, one trial using an ethanolic extract of Reishi did not report any meaningful alteration in circulating testosterone.
The key distinction lies between the effect on the 5-AR enzyme and the effect on the total hormone pool. Reishi may reduce the potency of androgens by limiting DHT conversion and action, but it does not reduce the body’s overall production or supply of testosterone. The focus of Reishi’s hormonal influence appears to be on the utilization of androgens at the tissue level rather than on the systemic concentration of the primary sex hormone.
Practical Considerations for Dosage and Extract Type
The specific form and concentration of the Reishi supplement are significant factors in determining its potential biological effect. Reishi contains hundreds of bioactive compounds, but the two main groups are polysaccharides (water-soluble) and triterpenoids (alcohol-soluble). The anti-androgenic effects, particularly 5-AR inhibition, are primarily attributed to the triterpenoids.
Therefore, the way the mushroom is processed dictates the final concentration of the relevant compounds. Extracts made with alcohol (ethanolic extracts) will contain a much higher concentration of the anti-androgenic triterpenoids compared to simple hot water extracts or powdered mushroom products. Studies that demonstrate the most potent 5-AR inhibition typically use these highly concentrated alcohol-based extracts.
The dosage also varies widely depending on the type of extract. A standard dose for a general Reishi extract, containing both polysaccharides and triterpenoids, can range from 1.44 to 5.2 grams daily. In contrast, studies using highly concentrated ethanolic extracts often involve much lower doses, sometimes as low as 6 milligrams of the concentrated compounds. Consumers should be aware that the high level of anti-androgenic activity observed in a lab setting often requires a specific, highly concentrated extract that may not be present in a standard Reishi powder.