Reishi is perhaps one of the most confusing ingredients we’ve seen when it comes to it’s impact on hormones. Some studies have shown that it raises testosterone levels, and others have shown that it actually lowers testosterone levels.
So, the question is of course, does Reishi raise testosterone or lower it?
Before we get too caught up in this however, we should also note that this is largely in animal studies, meaning that we don’t know how much most of this will carrier over to humans if at all. But, it’s interesting all the same. So, let’s get into a bit more information on the conflicting studies.
The first study found that consuming Reishi extract increased testosterone levels by about 25% in middle-aged male mice. It also made them horny… It doubled their pursuit of females, and led to a 37% increase in offspring production. 
However, another animal trial exploring the anti-androgenic effects of 20 species of mushrooms found that reishi mushrooms had the strongest action in lowering testosterone . But, it is also worth noting that the rats in this particular trial were castrated, and lowering testosterone was the desired outcome to deal with prostate related issues.
It could well be the case that Reishi stimulates something in the testes which leads to an increase in testosterone production which compensates for any other lowering effect. And of course in the case of the castrated rat studies this could result in lowered rather than increased testosterone production.
This ultimately means that when it comes to reishi’s effect on testosterone we’re onto a mixed bag.
Reishi effect on Testosterone in Human Studies
There have however been some indirect trials in humans. This means that whilst the studies weren’t being done specifically to study Reishi’s effect on testosterone it was noted.
One randomized, double-blind, placebo-controlled study was conducted that recorded the effects of reishi extract (dried and chipped with 30% ethanol) on testosterone concentrations.  The study itself was in relation to urinary tract issues, but it ultimately showed that there were not changes to testosterone levels in the men on the trial.
So Does Reishi Effect Testosterone Levels?
Ultimately the answer is most likely no, and the only evidence we really have is one trial on rats. It is however worth noting that neither the negative rat study or the negative human study particularly do anything to suggest that Reishi does not raise testosterone levels in males either. Seeing as the dose required in humans could simply be substantially higher. As is often the case with a lot of natural compounds that are eventually be shown to have use. It could be that it’s a specific compound within Reishi or a host of other things that caused the results in the first rodent trial.
1 - https://pubmed.ncbi.nlm.nih.gov/36432421/
2 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3693613/
3 - https://pubmed.ncbi.nlm.nih.gov/18097505/