I recently read an article from a male supplement producer that claimed that Nettle Leaf extract had no impact on testosterone in men. But when I clicked through the author’s links, I found that they had dramatically misrepresented the data–and even gotten a few things flat wrong.
It shouldn’t surprise anyone that Nettle Leaf is not in the product that they were advertising. The story is important because our site isn’t about selling a particular product–it’s about getting to the truth. In this case, the truth about Nettle Leaf extract (Urtica dioica) and testosterone is much more complicated than a simple yes or no.
Key Findings
✲ There is evidence that Nettle Leaf can increase available testosterone in three important ways.
✲ However, the Nettle Leaf itself does not increase testosterone production.
✲ Available data comes almost exclusively through animal studies; more human trials are necessary.
Bonus Finding:
✲ Nettle Leaf appears to be an excellent treatment for an enlarged prostate, reducing growth and improving urination and discomfort.s
Why Some Articles Say “No”
If an author isn’t experienced in science or nutrition writing, or if they’re selling a particular product, they can easily scan a document for the line that says “test group had no change in testosterone levels,” and then move on.
The trouble is, as I’ve mentioned before, scientists often are not looking for the same things we are. All of the studies the naysayer linked were about a disease called Benign Prostate Hyperplasia (BPH)–what most people call an enlarged prostate. Researchers have looked to herbal remedies, and landed on Nettle Leaf.
It is in their studies that scientists first saw Nettle Leaf as an effective prostate treatment. These and other successes led to a large-scale study of over 500 human men–with similarly effective results. But in this human study, they did not see testosterone levels increase.
Case Closed?
Hardly. Fact is, those researchers weren’t testing for testosterone, and only looked at serum levels (more on that later). Looking deeper at the issue of Nettle Leaf and hormones, a team of researchers suspected that, despite the “no change” in testosterone levels, there had to be a link–how else could it be helping the BPH?
These new researchers turned from rats and prostates, and looked to quails and the hormone itself. They found that Nettle can effectively stop the body from turning testosterone into estrogen. In case you’re not familiar, the male body’s primary source of estrogen is when a process called aromatase converts the male hormone into the female hormone in the brain. This is so common in older men, and causes so many health problems, that there is a class of medications designed around aromatase-inhibition.
This study of quails found that Nettle inhibits this process-naturally. This is the first way Nettle can help with testosterone availability–by stopping its conversion into estrogen. The reason we don’t see an increase in testosterone in the studies above has to do with the low percentage of free-testosterone compared to serum testosterone.
Two More Ways Nettle Leaf Helps
More research is conducted every year, finding correlations where we didn’t see any before in the search for how outcomes we’ve seen came about. Following yet another study of Nettle Leaf and BPH, two more outcomes were observed and later studied by latter researchers.
1. Prevention of Dihydrotestosterone (DHT)
DHT, a derivative of free testosterone, is the hormone most responsible for things like genital formation and body hair growth, as well as most other outwardly “male” characteristics. Sounds like a good thing, until you consider that it is taken out of that free testosterone which men already have so little of.
Research into BPH found that Nettle can prevent the conversion of free-testosterone into DHT by blocking a certain enzyme’s activity. And don’t worry, careful reader, I know that link only goes to an abstract–and that’s why I’ve got two more studies confirming that study’s results, one studying the prostate some more, and another showing the effects of herbal supplements in healthy young men. Both later studies referenced and confirmed the findings of the first. This is the second way Nettle Can help–keeping testosterone from turning into DHT.
2. Keeping Free-Testosterone Free
Free-testosterone, when actually free, helps men do all the things they want to keep doing in later life–like building muscle, keeping off fat, and staying healthy inside. Trouble is, as I’ve mentioned, nearly all of the testosterone in the body is bound up–bound into something called the Sex Hormone Binding Globulin, or SHBG. (“Globulin” refers to the blood cells it is attached to.) In an important study published in Planta Medica, researchers were able to show the third way Nettle helps with testosterone–by keeping it from binding with that globulin.
Unfortunately we don’t have access to that full report. But we do have something perhaps better. Based off of that doctor’s research, people began studying for the SHBG effect directly, and found that an average of 67% of free testosterone can be kept from binding into SHBG in the presence of Nettle Extract. That data, along with findings from three more studies, are provided to us from the European Medicines Agency.
Conclusion
It often takes a little extra time to sift through the highly complicated language of a scientific report to find out the answers we’re looking for. With some supplement ingredients it’s quite easy–because a study or nine already exists testing for the very outcome we’re looking for.
But with Nettle Leaf and Testosterone, we have to wade through quails and rat prostates to find the scientific data we’re looking for. In this case, we do not see direct evidence that Nettle Leaf can produce more testosterone in men. But we have seen hard data supporting the correlation between Nettle and free-testosterone. Which for many people is the real goal, in any case.