The supplement aisle at Whole Foods has quite a bit of real estate allocated exclusively towards maca powder and capsules. Likewise for Vitamin Shoppe and Vitamin World. You can even buy maca at Walmart, including a product called “V Shot Male Endurance Formula” which contains it.

If you have some balls, next time you’re in that aisle ask a stranger there why they are buying this root extract. You will find that most people are shelling out big dough for it, yet they really have no clue as to what clinical trials or research there is for the alleged health benefits they believe it has.

raw maca powder in dishWhat does maca root do for men? When it comes to reproductive benefits, the most commonly claimed are libido boosting, fertility, overcoming erectile dysfunction, and prostate health. Many believe it increases testosterone levels and helps with male pattern baldness/hair loss. Although not specific to men, using maca for energy boost or vitality, bodybuilding, and muscle growth are effects which have been claimed by both genders. While these are claimed for all color, red and black maca are perceived as being more potent.

But which of these alleged side effects have reputable research backing them? Which are greatly exaggerated or outright fabrications of the imagination?

Let’s review a sampling of the most noteworthy scientific studies relevant to these topics, to see what they may suggest about this popular superfood. Ordered from earliest to most recent, here they are…

(1) Cayetano Heredia University (Peru), 2001

Topics: fertility, sperm count, testosterone

Title: Lepidium meyenii (maca) improved semen parameters in adult men (1)

This is one of the earliest and no surprise, it was done in Peru which makes sense, given that this root grows high up in their Andean mountain range.

Does maca increase sperm count and volume? Finding that out was the goal of this study. In total 12 men were originally involved, however 3 had to drop out due to personal reasons. That left a total of 9 who finished; 3 single and 6 married men. Their ages ranged from 22 to 44 years old and were healthy with normal sexual vitality.

After a 3 day abstinence, semen samples were collected. The same was done after 4 months of receiving normal yellow maca supplements at a dosage of 1,500 or 3,000 mg per day. Various hormone levels were measured at both times, too.

The results?

semen levels before and after maca dosage

Reportedly there was an increase in sperm count, volume, consistency, and motility. The results are seen in the table.

Testosterone and hormone levels were not affected and therefore any fertility benefit is not because of those. The others measured were serum luteinizing hormone, prolactin, estradiol, and follicle stimulating hormone. By the way, that last one has nothing to do with hair follicles and therefore has no relation to hair loss side effects.

(2) Cayetano Heredia University (Peru), 2002

Topics: libido, testosterone levels

Title: Effect of Lepidium meyenii on sexual desire and its absent relationship with serum testosterone levels in adult healthy men (2)

Same university, same lead researcher (Gustavo F. Gonzales) as the first study we reviewed. In fact, he has conducted tons studies on it over the years; to date there are 38 papers on the NIH’s PubMed database which look at all kinds of maca side effects and benefits.

This was a double blind and placebo controlled trial. There were 57 healthy men who participated, ranging in age from 21 to 56 years. It’s worth noting they were all young to middle age, as no seniors or elderly men were used. That’s too bad because obviously there are higher libido and vitality issues with older age (and hence, those are the men who are even more interested in this possible advantage).

testosterone levels chart

Does maca increase testosterone levels? Not according to this study. The amount vs. placebo was not statically different.

They were instructed to take 3 tablets per day over the course of 12 weeks. For their daily dose, each man received either maca in a dose of 1,500 mg/3,000 mg, or a placebo. None of them knew what they were getting.

The results?

Those receiving the tablets did not experience a change in testosterone or other reproductive hormone levels, however they did experience an improved sexual desire. The maca supplement side effects were no different than what the placebo group experienced.

(3) Cayetano Heredia University (Peru), 2007

Topics: prostate health, frequent urination

Title: Effect of two different extracts of red maca in male rats with testosterone-induced prostatic hyperplasia (3)

Another study by Gonzales and his team. Keep in mind this is a rat study, it didn’t involve humans.

chart of prostate size after maca extract

Does maca root help the prostate? Here’s how it measured up against a leading drug for enlarged prostate treatment (in rats, not humans).

Testosterone, especially too much of it, can make your prostate bigger than it should be, which can lead to all sorts of nasty side effects like frequent urination and sexual vitality and fertility issues. This condition is called prostatic hyperplasia.

In this study, researchers intentionally caused the male rats to experience prostatic hyperplasia by administering them excess testosterone. Then, they administered extracts of red maca to see if it had any effect. It’s important to remember that a rat’s prostate is quite different from that of a man.

The results?

Control = placebo
RM-H = hydroalcoholic extract of red
RM-AQ = freeze-dried aqueous extract of red
Finasteride = leading prescription prostate medication

The prostate size was reduced in the rats who received red maca extract, which contained 0.1 mg of benzylglucosinolate. That’s a natural compound in the root which is suspected to be the cause.

For ventral prostate weight it actually performed better than finasteride, but for seminal vescicles weight the results were almost the same as placebo.

(4) Northumbria University (UK), 2009

Topics: libido, athletes, muscle gain and building

Title: A pilot investigation into the effect of maca supplementation on physical activity and sexual desire in sportsmen (4)

athletic performance in placebo compared to maca

Even if performance improved, it doesn’t mean better muscle growth.

For this study, the researchers recruited 8 endurance athletes (experienced male cyclists) from a local cycling club. The following averages were provided for them; 30 years of age, 5′ 8″ tall, and 155 lbs.

All eight men completed a 40 km cycling timed trial. Then after 14 days of receiving either maca root powder or a placebo, they completed it again. Before each trial, each man took a Sexual Desire Inventory (SDI). That’s a 14 question test to measure characteristics of sexual desire, or to put it more plainly, horniness.

The results?

The group receiving the root extract achieved greater improvement in cycling time as well as higher sexual desire or libido according to the SDI questionnaire. However given that both groups had experienced better times and given the tiny sample size, it’s tough to say how statistically significant this may be.

(5) Morgagni-Pierantoni Hospital (Italy), 2009

Topics: erectile dysfunction, fertility, libido

Title: Subjective effects of Lepidium meyenii extract on well-being and sexual performances in patients with mild erectile dysfunction: a randomized, double-blind clinical trial (5)

This study involved 50 Caucasian males who all had mild erectile dysfunction. What constitutes “mild” they did not say. Each guy received a 2,400 mg daily dose of dry maca extract or a placebo. The treatment lasted for 12 weeks.

The results?

In terms of psychological performance, both the supplement and placebo experienced “significant improvement.”

Now that may sound like there’s zero benefit involved, but in reality results like this aren’t that unusual when it comes to men and ED. Just the belief that you might be getting a substance to help achieve an erection is sometimes enough to cause improvement (women probably won’t understand that performance is just as much a psychological as it is a physiological side effect). Plus between the two, it’s also stated that the maca benefits for men were higher versus placebo.

In terms of physical and social performance, only those the receiving supplements of maca experienced “significant improvement.”

Overall, the conclusion was that that it provided a “small but significant effect” on the men who have mild ED.

(6) Cayetano Heredia University (Peru), 2011

Topics: alcohol/drinking, memory, hangovers

Title: Dose-response effect of black maca (Lepidium meyenii) in mice with memory impairment induced by ethanol (6)

frothy beer glassAs mentioned there are dozens of studies by Gonzales but most cover the same topics repeatedly. Here is one that’s different from the rest; the benefits of black maca on drunk mice. While alcohol technically is not related to libido, some men may argue otherwise!

Gender was not specified, so presumably both males and females were used.

The mice were divided into the following; (1) control group, (2) those receiving 20% ethanol/alcohol, (3) and those receiving the 20% ethanol plus ascorbic acid and black maca extract in 3 different dosage amounts.

The results?

The mice who were treated with the ascorbic acid (vitamin C) and black root extract reportedly took less time to find a hidden platform than the control group.

The supplement combination was also claimed to “reverse” some side effects of the alcohol. It was said to improve memory impairment and that effect was correlated with the dosage received. One reason was believed to be due to the polyphenol compounds in the supplement.

It probably a matter of when, not if, the black maca hangover cure is claimed by dubious marketers. Or that it’s a vitality supplement for drinking. Remember this involved mice, not people! Furthermore it had pure vitamin C involved, which obviously would be a potent antioxidant in and of itself.

We are highly skeptical if there are any advantages of mixing maca root and alcohol. If this root really is a stimulant or energy booster, the interaction between it and booze seems like a bad idea to begin with. Anyone who has done Red Bull and vodka knows it has terrible side effects!

(7) Xi’an University (China), 2015

Topics: exercise fatigue, muscle recovery, bodybuilding, physical vitality

Title: The Research on the Impact of Maca Polypeptide on Sport Fatigue (7)

laying on bench lifting barbellsUsing maca before or after a workout has been popular with bodybuilders for years. Men use it before they hit the gym, as a pre-workout supplement because they believe it helps increase energy and support muscle growth afterward.

Even though there are testimonials on bodybuilding forums which vouch for those claims, to date there has been almost no research looking at these alleged exercise advantages. Does maca root build muscle? No studies have been done for weight lifting or to evaluate muscle growth. We mentioned the cycling study, but that was more focused on recovery and endurance. It did not measure muscle growth.

This is one other study which may be relevant to these topics. How many mg of maca should I take for bodybuilding and exercise? No human study has evaluated that and this study only involves swimming mice, so it’s not relevant to human biology, though the results may still pique your interest.

There’s only one author listed for it, which is unusual as the vast majority of studies list an entire team.

The goal of the study was to measure exercise fatigue, which is defined as being caused by physical and mental stress for prolonged periods of time (i.e. intensely working out). Side effects from sports fatigue are listed as loss of appetite or eating less food after, sleeping problems, and decreased physical ability during the muscle recovery time.

This researcher took 40 mice who were all males and divided them into four groups, each having a different concentration of the root in their food.

Group A: 5g per liter (0.9% of food)
Group B: 10g per liter (1.8% of food)
Group C: 20g per liter (3.6% of food)
Group D: control group, none added (0% of food)

The research did not provide the percentages listed, we came up with those. Converting grams to liters isn’t black and white, since gram is a weight and liter is a volume. We estimated that maca powder has the same weight as typical baking flour (1 mL = 0.57g) and based on that assumption, we converted the concentration to a percentage and added those estimates above.

glucose levels after maca supplementation

aqua = glucose levels at end of study, green = standard error estimate

He didn’t specify which variety was used, but presumably it was the white or yellow. However in the intro, he discusses all the colors, including black and purple maca root. He states that the darker the color, the higher the concentration of active ingredients. Between purple maca versus black maca, he claims that black is more rare and considered to be “best of breed.”

They were fed these concentrations for 2 weeks and during that time, adaptive swimming training was done.

The results?

After the 2 weeks, blood glucose, creatinine, and urea nitrogen levels were measured in their blood.

The blood glucose levels were higher in the 3 dosage groups versus the placebo group.

bun test graphThe creatine levels between the 4 groups had no statistical difference.

The urea nitrogen (BUN) levels for groups with the supplement were higher than the placebo. The researcher claims this shows it can effectively reduce nitrogen that is generated during exercise-induced fatigue.

The conclusion was that there are exercise recovery benefits. Not in men necessarily, but at least in the mice. The amount correlates with the dosage (higher doses = better recovery).

Bogus benefit claims

Right off the bat, let’s shoot down the claims which have little to no research.

Hair growth

man going baldWe are unable to locate a single medical study or research paper in the NIH database about maca benefits for hair. To the best of our knowledge, using it to treat hair loss has not been studied – not in humans or animals – as part of any legitimate study that has been published in a peer reviewed medical journal.

What makes this particularly disturbing is that we see a number of blogs and supplement marketing which blatantly claims that maca helps with hair regrowth and/or “strengthens and fortifies” the hair follicles.

Guys, sorry but there is nothing to suggest this is an herbal remedy for male pattern baldness.

Testosterone

This is another that is clearly a figment of imagination, at least based on the research to date.

Gonzales may be the foremost authority on the maca root research. He and his team have specifically measured this hormone in more than one study and found that maca and testosterone levels are unrelated. It’s true that most of those were for mice, but the human studies haven’t claimed it either.

It’s not a testosterone booster for men, plain and simple.

That being said, 2017 research using rats found that their 3ß-HSD testicular gene expression was increased when they were fed maca extract as 2% concentration of their diet.  In turn, this genetic behavior boosted their testosterone production. No one has checked if that gene or similar is being affected in humans. (8)

Claims which need more research

couple making out in bedFor most of the other claims, there might be something to them, but the problem is that research is way to preliminary to draw any kind of conclusions. Right now, it’s not appropriate for supplement manufacturers to claim that maca increases libido. Even more so for claims about muscle/gain recovery, as there are even fewer studies related to that and only two of which involve humans.

Out of all the research, those related to fertility benefits seem to be the most intriguing. When it comes to maca root for men, certainly the studies involving sexual libido/vitality, sperm count, and ED are of interest to many. But remember it’s a very limited body of research and only future studies and human clinical trials will tell us what’s fact and what’s fiction.

Considering that all health benefits are unproven, when you buy maca supplements it probably doesn’t make sense to get the expensive stuff (unless you can easily afford the black extract). A reasonably priced yellow powder or basic extract capsule makes more sense.

There are plenty of respectable brands on the market that are a decent value:

NOW Foods Maca 500 mg (250 Vcaps)
Navitas Naturals organic maca gelatinized powder (1 lb bag)
Healthworks raw maca powder USDA certified organic (2 lb bag)


These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.