Everyone seems to be looking for the next big herbal supplement, and unfortunately it can seem like some supplement makers have the policy of “the more the merrier” in their ingredient lists. I’ve seen Maca on nearly a third of male supplement labels over the years.
In this short article, I’ll explore whether Maca Root (Lepidium meyenii) actually increases testosterone, and where some of the confusion about its effects may have come from.
✲ Most Maca studies have derived their outcomes from self-reported data showing Maca is an effective aphrodisiac, the mechanisms of which remain unclear.
✲ There is no hard data, however, that Maca has any influence, direct or indirect, on testosterone levels or production in men.
✲ Some small data sets have indicated that it increased testosterone production in the Leydig cells of lab animals.
What Maca Might Do
I’ll only touch on a few articles, because they are representative of the whole field, and in the main the research into sexual function and health of men, especially aging men, supports the idea that Maca can help with arousal and dysfunction.
A literature review of 17 databases–not studies, but whole databases–was published a few years ago, and found significant improvements in male sexual performance in three separate randomized clinical trials. This might sound like a strong positive correlation, but keep in mind that in over 17 databases they only found three studies with a correlation.
I followed up on their leads, and found two studies, one pointing to a correlation and the other gainsaying that conclusion. The positive test was a randomized, double-blind, placebo-controlled trial that showed an increase in sexual performance and function–based on self-reported data.
To muddy the waters, the other study was… another literature review. Very disappointing, because they don’t publicly disclose their data sets. Conclusions on testosterone, at this point, are not actually conclusive.
More Muddy Waters
So we have a lot of reviews of data that are only available to other research institutions, and then one publicly available study showing that Maca improves sexual health. Where do we go from there?
We can look back at the clinical trial and see that they found no difference in testosterone among the Maca group and the control group. So now we’re left wondering what the mechanism really is, if indeed there is one.
To try and answer that we have, again, conflicting data. From a set of clinical tests conducted on laboratory rats, we have data showing that Maca increased the level of testosterone in the Leydig cells (hormone producing cells in the testes). But they don’t use the word “significant.” This is actually a bigger deal than some may think, because that word, “significant” deals with statistical analysis on which scientists rest their reputations and careers–if their math could show a real correlation, they would have used that trigger word.
Further, we have a study of human men wherein several preparations of Maca were tested. The aim of the study was to see if Maca had something called Androgen Receptor compatibility. To explore this will take a brief paragraph.
When the body wants to perform a function, cells trigger one another with enzymes, proteins, minerals, hormones, or electrical impulses. Androgen Receptors (AR) are so called because they are the receiving end of signals from other cells to produce androgenic hormones, i.e., testosterone in men.
Now, in this study, despite their stated aim of AR research, scientists instead tested for something called the glucocorticoid response element, or GRE. This receptor is strikingly similar to AR–but it does not lead to testosterone production. In any case, the tests failed, and the scientists saw no GRE response from Maca.
What does that mean? Possibly everything, possibly nothing. GRE and AR are very similar in how they react to compounds, but we can’t say definitively that “x didn’t stimulate GRE, and therefore won’t stimulate AR to testosterone production.” At least, I won’t state that here, because the data as I’ve read it does not support that conclusion.
It’s difficult to draw conclusions when the scientific community is so scattered. There has been no convincing evidence on either side of the Maca-testosterone correlation question. More studies are needed–studies that actually test the specific outcome of testosterone production in men.
In the meantime, any claims that Maca definitely does or definitely does not increase testosterone should be met with skepticism–for both those claims and their authors.