What maca may do for men, based on current evidence

Maca root has been studied most closely for its effects on sexual function in men. The strongest evidence comes from human trials showing that men who took maca powder or extract reported improvements in sexual desire and erectile function after 8 to 12 weeks of use. A 2009 randomized controlled trial published in BMC Complementary and Alternative Medicine found that men taking 2.4 grams of maca daily reported greater satisfaction with sexual intercourse compared to those taking placebo. A separate 2010 trial in the same journal showed similar results for erectile function.

However, these improvements were modest rather than dramatic. Men in the studies reported changes they could notice, but the effect size was smaller than what prescription medications like sildenafil produce. The mechanism is not fully understood—maca does not appear to work the same way those drugs do. Researchers have proposed that maca may increase nitric oxide availability in blood vessels, improve mood, or affect hormone signaling, but human studies have not yet confirmed which of these (if any) is the primary pathway.

Beyond sexual function, maca has been studied for effects on mood, energy, and fertility in men, though the evidence is thinner. Some small trials suggest it may improve general well-being or sperm parameters, but these findings come from studies with fewer participants and less rigorous design than the sexual function research.

Key Takeaways

  • Human trials show men taking maca reported improvements in sexual desire and erectile function after 8 to 12 weeks, but the effect was smaller than prescription medications produce.
  • The strongest evidence comes from randomized controlled trials, though most included fewer than 100 participants and lasted 12 weeks or less.
  • How maca works in the body remains unclear; proposed mechanisms include effects on blood vessel function, mood, or hormone signaling, but none has been proven in humans.
  • Maca appears to be well tolerated in the doses studied (1.5 to 3.5 grams daily), with few reported side effects beyond mild digestive upset in some users.
  • Research on maca and fertility, energy, or mood in men is limited and comes mostly from small studies, so claims in these areas are less established.

How the human trials were designed and what they measured

The most credible studies on maca and male sexual function used a randomized, double-blind, placebo-controlled design—the gold standard for testing whether a substance actually works rather than just making people feel better because they expect it to. Participants were assigned randomly to receive either maca powder or an identical-looking placebo, and neither the participants nor the researchers knew who received which until the study ended.

Researchers measured outcomes using validated questionnaires like the International Index of Erectile Function (IIEF) and the Sexual Desire Inventory (SDI), which ask men to rate specific aspects of sexual response on a numerical scale. This approach is more reliable than straightforward asking "Do you feel better?" because it captures changes in particular domains—desire, arousal, orgasm, satisfaction—rather than a vague overall impression.

Most trials lasted 8 to 12 weeks and included maca doses between 1.5 and 3.5 grams daily, usually divided into two or three doses. Participants were typically men with mild to moderate erectile dysfunction or men without diagnosed dysfunction who wanted to assess changes in sexual function. The studies were small by pharmaceutical standards—most enrolled 40 to 100 men—which means the results are suggestive but not definitive.

What the evidence does not show

Maca has not been tested against prescription erectile dysfunction medications in a head-to-head trial, so claims that it works "as well as" or "better than" those drugs are not supported by evidence. The modest improvements seen in maca trials are consistent with a mild effect, not a replacement for medications that produce larger changes in most men who take them.

Long-term safety and effectiveness beyond 12 weeks are largely unknown. Most published trials lasted three months or less, so there is no human data on what happens if someone takes maca for a year or longer. Animal studies have not raised red flags for toxicity at typical doses, but that is not the same as confirming safety in humans over extended periods.

Maca's effects on fertility, testosterone levels, mood, and energy in men come from very small studies or animal research. While some results are promising, they are not yet strong enough to support confident claims. A 2016 review in Andrologia concluded that evidence for maca and male fertility was "limited" and that larger, longer trials were needed.

Why the mechanism remains uncertain

Maca root contains compounds including glucosinolates, alkaloids, and various amino acids, but researchers have not identified which (if any) are responsible for reported sexual effects. This matters because understanding the mechanism helps predict who might benefit, whether maca could interact with other substances, and whether a more potent version could be developed.

One proposed mechanism involves nitric oxide, a signaling molecule that relaxes blood vessel walls and improves blood flow to the penis. Some laboratory studies show that maca extracts can increase nitric oxide production in cells, which would theoretically improve erectile function. However, this has not been demonstrated in human blood vessels or tissues.

Another hypothesis is that maca affects mood or reduces anxiety, and that improvements in sexual function are secondary to feeling better overall. A few small trials found that maca users reported better mood or less stress, but the studies were not designed to test whether mood changes caused the sexual improvements or were straightforward correlated with them.

Dose, form, and what to expect if you use maca

The doses used in human trials ranged from 1.5 to 3.5 grams daily, usually taken as a powder mixed into food or water, or as a capsule. Most studies divided the dose into two or three smaller amounts throughout the day rather than one large dose. There is no established "optimal" dose because the trials did not systematically compare different amounts.

Maca is sold in several forms: raw powder, gelatinized powder (heat-treated to reduce fiber and improve digestibility), extracts, and capsules. The trials used mostly powder or capsules, so those forms have the most direct evidence. Extracts are more concentrated but have been studied less in humans, so it is unclear whether a smaller dose of extract produces the same effect as a larger dose of powder.

If improvements occur, they typically appear after 4 to 8 weeks of consistent use, not when ready. The trials measured changes at 8 to 12 weeks, and most showed that benefits continued or increased over that period. Stopping maca appears to reverse the effects, based on the trial designs, though this has not been formally studied.

Side effects and interactions reported in trials

Maca was well tolerated in the human trials published so far. The most common side effects were mild and gastrointestinal—nausea, bloating, or loose stools—reported by a small percentage of participants. No serious adverse events were documented in any of the randomized controlled trials, and blood tests showed no concerning changes in liver or kidney function.

However, the trials were short (8 to 12 weeks) and involved relatively small numbers of people, so rare side effects or long-term problems could exist but straightforward not have been detected. Maca has not been formally tested for interactions with medications, so if you take blood pressure drugs, blood thinners, or other medications, you should discuss maca with your doctor before starting it.

Maca is a food plant and is generally recognized as safe by the FDA when used in typical food amounts, but this does not mean it has been tested for safety at the supplement doses used in trials. Pregnant or breastfeeding women should avoid maca supplements because safety in those populations has not been studied.

How maca compares to other supplements marketed for male sexual function

Maca has more human trial evidence than many other plant-based sexual function supplements. Ginseng, for example, has some randomized controlled trials showing modest benefits for erectile function, similar in scope to the maca evidence. Tribulus terrestris and horny goat weed have fewer rigorous human trials and weaker evidence overall.

The prescription medications sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra) have been tested in large, long-term trials and produce larger and more consistent improvements in erectile function than maca does. They work through a clear mechanism—inhibiting phosphodiesterase-5 to increase blood flow—and their effects are well understood. Maca's mechanism remains uncertain, and its effects are smaller.

If you are considering maca, it may be worth trying if you have mild sexual concerns and prefer a plant-based approach, but it should not be viewed as a substitute for medical evaluation. Erectile dysfunction can signal underlying cardiovascular or hormonal problems that deserve professional assessment, regardless of whether you choose maca, medication, or another approach.

Frequently Asked Questions

Does maca increase testosterone?

The human evidence is limited. A few small studies found no significant change in testosterone levels in men taking maca, while one small trial reported a modest increase. The largest and most rigorous studies did not measure testosterone, so it is unclear whether maca's sexual effects depend on hormone changes or work through a different pathway. If testosterone is a concern, blood testing by a doctor is the appropriate first step.

How long does it take maca to work?

In the trials, improvements in sexual function typically appeared after 4 to 8 weeks of consistent daily use and continued through 12 weeks. Some men reported changes sooner, but most studies measured outcomes at 8 to 12 weeks, so that is the timeframe with the most evidence. If you see no change after 12 weeks, it is unlikely maca will help.

Can I take maca with erectile dysfunction medication?

Maca has not been formally tested alongside prescription medications like sildenafil. Because maca's mechanism is not fully understood, there is a theoretical possibility of interaction, though no cases have been reported. Discuss any supplement with your doctor before combining it with medication, especially if the medication affects blood pressure or blood flow.

Is maca safe to take long-term?

Human safety data beyond 12 weeks does not exist. Maca is a food plant and appears safe in the short term based on trial evidence, but long-term safety in supplement doses has not been studied in humans. If you want to use maca for months or years, discuss this with your doctor, who can monitor for any unexpected effects.

What if maca does not work for me?

Not everyone responds to maca, and the effect when it does work is modest. If you see no improvement after 8 to 12 weeks, it is reasonable to stop. Erectile dysfunction has many causes—cardiovascular, hormonal, psychological, or medication-related—and a doctor can help identify which might explore to you and suggest approaches with stronger evidence or better fit for your situation.