Big Brains Show Probiotic Increases Testosterone

I don’t know much about probiotics, but when researchers from MIT publish a study on something that increases testosterone I listen [1].  Especially when they say this:

probiotic increases testosterone“Ultimately, dietary L. reuteri or other probiotic supplementation may provide an alternative natural approach to prevention of male hypogonadism, absent the controversy and side-effect risks of testosterone replacement therapy [9–10,13,20].”

Pretty exciting, right?  So here’s what they did and why they did it.  First the researchers previously published a study in which they found the priobiotic Lactobacillus reuteri made rats appear younger.  Notably the benefits were stated as ” luxuriant hair” and no diet induced obesity (unlike their brothers and sisters).  They attributed this to a down-regulation of pro-inflammatory cytokine IL-17.  Cytokine IL-17 has been linked to various diseases such as asthma, psoriasis, and arthritis.  They believed this improved immunity in the stomach and intestines, and subsequently improved overall health/immunity.  In all cases they noted larger testicles, and a more dominant male behavior in the rats given lactobacillus reuteri (see photo on right).

Probiotic Lactobacillus Reuteri Gets Put to the “Test”

6-8 week old mice were given one of two diets.  A control diet, or a diet designed to mimic an American “fast food” diet (high fat, low fiber).  Mice were given lactobacillus reuteri for 12, 20, 28, and 40 weeks.  The mice were given a purified strain of lactobacillus called ATCC PTA 6475.  This particular strain is patented for the use of inflammation reduction in animals.  They were given a dose of 3.5 x 10^5 organisms/mouse/day.  They found the following:

  • probiotic increases testosteroneTesticular weight increased in the normal diet of mice fed lactobacillus reuteri
  • Testicular weight increased in the fast food diet mice, and they maintained a “lean physique” unlike the control group
  • Seminiferous Tubule (where sperm is produced in the testicles) count did not increase
  • Seminiferous Tubule cross sectional area increased, as a result of germ cell increases.
  • Both diets fed with lactobacillus reuteri had significantly higher leydig cell count
  • Both diets fed with lactobacillus reuteri had significantly increased testosterone (see image on right)

To test whether the probiotic down-regulation of cytokine IL-17 resulted in these improvements, they also treated mice with anti-IL17A antibody.  This depletes cytokine IL-17 in the testicles.  They found that all the improvements seen with probiotic lactobacillus reuteri supplementation were also true with depletion of cytokine IL-17.  The authors believed this to be a result of an increase in another cytokine Interleukin-10 (IL-10).  Reduced IL-10 has been tied to obesity, general inflammation, and poor immune response.

The next thing we need is some human research, but this certainly makes me want to go out and buy some good probiotic containing yogurt.  The authors concluded the study with this statement:

“Such microbial immune system re-programming may ultimately target other diseases linked to low testosterone including increased body fat, decreased muscle and bone mass, weak physical and mental performance, and depressed mood [8–11] for more healthful longevity.”

– Travis DeGraff


One thought on “Probiotic Increases Testosterone – L. Reuteri

  1. Randy says:


    Is there any way to get the exact lactobacillus reuteri that is in the study? I bought a product that was lactobacillus reuteri but had to return because it is a different one than from the study. Apparrantly there are different versions of it. If you know please tell me how I can purchase this particular probiotic.

    Thank you very much.


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