If you've been scrolling through health websites or wandering the supplement aisle, you've probably encountered maca root. The Peruvian root vegetable has built a reputation as a natural solution for everything from menopausal symptoms to athletic performance. But what does the actual science say? Which claims hold up in clinical research, and which ones don't? More importantly, what should you realistically expect if you try it?

The answer is more nuanced than marketing suggests. Maca has solid evidence for some uses and weaker support for others. It's safe, but dosage matters significantly. Most importantly, it doesn't work the way many people think it does. Let me walk you through what the research actually shows.

What Is Maca, Actually?

Maca (Lepidium meyenii) is a root vegetable from the Andes mountains of Peru, related to broccoli and cabbage. Peruvians have used it for at least 2,000 years, and modern research has been examining whether its traditional claims about sexual function, fertility, and hormonal balance hold up to scientific scrutiny.¹

The key finding right at the start: maca doesn't work like you might expect. It's not a hormone supplement, and it doesn't directly increase testosterone or mimic hormone action in your body. Instead, it appears to work through more subtle mechanisms; optimising your existing hormone system, affecting brain chemistry, or improving cellular energy production, depending on what you're using it for.²

Why Maca Works Differently Than People Think: The Hormonal Misconception

This is the most important thing to understand before considering maca: it doesn't add hormones.

Research clearly shows that maca doesn't contain testosterone-like compounds that can bind to androgen receptors in your body.³ In studies of healthy men taking 1.5 to 3.0 grams daily for up to 12 weeks, sex and pituitary hormone levels didn't change.⁴ So if you're worried that maca will masculinise you, or that it will cause hormone-related side effects, the evidence suggests it doesn't work that way.

Instead, maca appears to work by optimising the hypothalamus-pituitary-ovarian axis, the system that controls your body's own hormone production. Think of it as tuning an engine rather than adding fuel. In menopausal women, researchers have documented that pre-gelatinised maca significantly increases the body's production of oestradiol (a form of oestrogen), progesterone, and other regulatory hormones; it does this by helping the body make these hormones itself, not by supplementing them directly.⁵

This distinction matters because it means maca doesn't carry the same risks as hormone replacement therapy (HRT), yet it still produces measurable hormonal improvements in women going through menopause.

Menopausal Symptoms: Maca's Strongest Evidence

This is where maca has the most impressive research backing it.

The numbers are striking: between 74% and 87% of women with menopausal symptoms experienced significant symptom relief when taking maca. That means roughly 3 out of 4 to 7 out of 8 women reported meaningful improvement.⁶

More specifically, in women taking pre-gelatinised maca over several weeks, menopausal symptom scores improved substantially in some trials.⁷ That's not just a small improvement; that's dropping more than halfway down the symptom scale.

 Figure 1: Percentage improvements across menopausal symptoms. Women experienced relief not only in physical symptoms like hot flushes and night sweats, but also in anxiety, depression, and sexual dysfunction.

The improvements extended across multiple symptoms simultaneously. Hot flushes showed significant reductions in both frequency and severity. Night sweating improved dramatically. But maca didn't just address the physical symptoms—anxiety and depression improved measurably, as did sexual dysfunction. This is important because menopause affects women's psychological wellbeing as much as their physical health.⁷

Equally important is how maca achieved these results. A systematic review of all four randomised clinical trials on maca for menopausal symptoms found that all four demonstrated mostly favourable effects using established assessment tools.⁸ This consistency across independent research groups strengthens confidence in the finding.

After 8 months of treatment, researchers observed an important pattern: follicle-stimulating hormone (FSH) levels significantly decreased while luteinising hormone (LH) levels increased. Oestradiol and progesterone rose. This is the pattern you want to see; it shows the body's own hormone-producing system is rebalancing, not just being supplemented artificially.⁹

The bottom line for menopausal women: Maca has the strongest evidence of any use discussed in this article. If you're dealing with hot flushes, night sweats, mood changes, or sexual issues related to menopause, maca has good research support.

Sexual Function and Erectile Dysfunction: Beyond Placebo

Sexual dysfunction affects millions of people, and options feel limited. Maca shows measurable benefits in this area, though the gains are modest.

Mild Erectile Dysfunction

In a randomised, double-blind, placebo-controlled trial of 50 men with mild erectile dysfunction, researchers gave participants either 2.4 grams of maca daily or placebo for 12 weeks. The results were clear: men receiving maca improved on the International Index of Erectile Function (IIEF-5) by 1.6 points, whilst the placebo group improved by only 0.5 points.¹⁰ This represents a 3-fold greater improvement with maca than placebo, a statistically significant advantage that translates to real-world benefit.

This matters because it shows the benefits aren't just psychological. Yes, both groups improved (expectation and psychology matter), but maca provided a meaningful pharmacological advantage beyond what you'd expect from placebo alone.

Low Testosterone Symptoms

A more recent randomised, double-blind, placebo-controlled trial examined men with symptoms of late-onset hypogonadism (essentially, low testosterone symptoms). Eighty men received either maca or a placebo. Those taking maca showed significant improvements in sexual function measures, and researchers concluded that "maca may be considered an effective and safe treatment" for these symptoms.¹¹

What makes this finding particularly interesting is that these benefits occurred without any measurable increase in testosterone levels—yet another reminder that maca's mechanisms aren't the simple "add hormones" story that marketing sometimes suggests.

Sexual Dysfunction from Antidepressants (SSRIs)

Between 40% and 60% of people taking SSRIs (selective serotonin reuptake inhibitors) for depression experience sexual side effects. It's a major quality-of-life issue, and people often struggle to find solutions.

In a dose-finding study, women on SSRIs who took 1.5 grams of maca daily showed no significant improvement in sexual dysfunction. But those taking 3.0 grams daily showed significant improvement in sexual dysfunction scores.¹² This dose-response relationship is crucial; it shows that there's a threshold dose needed for effect. If someone tries maca at an under-therapeutic dose, they won't see results.

Importantly, the beneficial effects of maca on sexual dysfunction in these women aren't related to oestrogen or androgen content in the supplement itself.¹³ This reinforces that maca works through different pathways; possibly through dopamine and other neurotransmitter systems rather than through direct hormone addition.

 Figure 2: Maca compared to placebo across three different sexual dysfunction conditions. Maca showed 3-4 times greater improvement than placebo across conditions.

Male Fertility and Sperm Quality: Promising but Mixed Results

For men dealing with infertility or low sperm counts, the evidence on maca is encouraging but inconsistent.

Sperm Concentration

In one 12-week study, men taking 2 grams of maca daily had sperm concentrations of 15.04 million per millilitre, compared to 10.16 million per millilitre in the placebo group.¹⁴ That's approximately a 48% improvement, a significant quantity difference that matters for fertility outcomes.

In vitro (laboratory) studies showed even more dramatic improvements. When maca extract was added to sperm samples in the lab, sperm motility (the ability to swim) jumped from 53.9% in control medium to 82.1% in maca-containing medium; a 28.2 percentage point improvement.¹⁵ However, it's important to note that laboratory findings don't always translate directly to what happens in living men.

The Inconsistency Problem

Here's the complication: more recent research found less clear-cut results. A newer randomised clinical trial found no significant differences between maca and placebo in semen volume, sperm motility, or sperm morphology (shape).¹⁶ So whilst some studies show improvement in sperm concentration and motility, not all parameters show consistent benefit across all studies.

A systematic review examining five studies (three randomised clinical trials and two observational studies) concluded there is "limited evidence" for maca's effectiveness on semen quality.¹⁷ But, and this is crucial, "limited evidence" doesn't mean "no effect." It means the evidence is real and positive, but sample sizes are small, methodology varies between studies, and we need more rigorous trials.

 Figure 3: Sperm quality parameters with maca supplementation. Concentration shows the most consistent benefit (48% improvement), whilst other parameters show more variable results.

The practical message for men trying to conceive: Maca may help, particularly for sperm concentration, but it shouldn't replace standard fertility evaluation and treatment. It may work as an adjunct approach, but have realistic expectations.

Energy, Athletic Performance, and Fatigue: Where the Research Gets Complicated

Maca is heavily marketed for energy and athletic performance. The story here is more complicated than marketing suggests, primarily because animal research shows much stronger effects than human trials do.

What Animal Research Shows

In animal studies, the effects are impressive and consistent. Rats supplemented with maca showed significantly increased swimming time to exhaustion, decreased blood lactate levels (a fatigue marker), and better energy utilisation. Mouse studies on maca polysaccharides showed they could extend swimming duration, accelerate swimming speed, and reduce the accumulation of fatigue markers in the blood.¹⁸

Mechanistically, researchers have documented that maca increases mitochondrial biogenesis; essentially, it helps cells create more of their own "power plants" for energy production. It upregulates important energy metabolism regulators like SIRT1 and increases the expression of genes involved in the citric acid cycle (the central energy production pathway in cells). It also enhances antioxidant defences that protect cells from the oxidative stress that accumulates during intense exercise.¹⁹

What Human Research Actually Shows

The human evidence is far more modest.

A systematic review and meta-analysis including 21 studies reported a large pooled effect for physical performance outcomes. But here's the critical context: this meta-analysis combined animal studies (which showed strong, consistent effects) with human studies (which showed more modest, mixed effects). When you average very strong animal data with modest human data, you get a "large effect" overall; but the human data alone tells a more nuanced story.²⁰

In a study of trained male cyclists over 14 days, maca improved their 40-kilometre time trial performance compared to their own baseline, but when compared to a placebo in a properly controlled way, the improvement was not statistically significant.²¹ This illustrates a common problem in supplement research: showing improvement versus your own baseline (which many people can do through improved motivation and psychology) isn't the same as beating a placebo.

Most striking is a recent study of elite basketball players. Researchers gave them either 2,000 milligrams of maca daily or a placebo for two weeks in a crossover design. They measured countermovement jump height, jump shooting accuracy, repeated sprint performance, fatigue index, and blood lactate clearance. The result: no significant differences between maca and placebo on any measure.²² Researchers concluded that "2-week maca supplementation did not provide ergogenic benefits" in these elite athletes.

However, an 8-week study of elite women's handball players did show improvements in isokinetic muscular performance (strength measurements), suggesting that duration matters—2-week trials may be too short to detect benefits.²³

The Energy Mechanism: Macamides

Maca contains unique compounds called macamides, long-chain fatty acids chemically bonded to benzylamine. In animal studies, specific macamides improved endurance capacity by increasing liver glycogen levels, decreasing blood urea nitrogen (a fatigue marker), decreasing blood lactic acid, and reducing lactate dehydrogenase (an enzyme indicating muscle damage).²⁴ The research notes a dose-response effect: higher doses produce greater benefits, though the optimal human dose remains unclear.

What This Means for You

For general energy: Most human trials used 3 grams daily. In one trial comparing black and red maca extracts at this dose over 12 weeks, red maca showed better effects on energy and quality of life parameters than black maca and placebo.²⁵ But the improvements were modest, not transformative.

For athletic performance: The evidence is weak. If you're hoping for dramatic performance gains, maca isn't that supplement. Short-term supplementation (2 weeks) showed no benefit in elite athletes. Longer supplementation (8 weeks) showed some strength improvements in one study. Endurance activities might benefit more than strength or power activities, but the evidence is limited.

The honest assessment: animal research paints a rosy picture, but human evidence is more cautious. Maca is a mild supplement for energy, not a performance-enhancing drug. If you try it, give it 8-12 weeks, not 2 weeks, and have realistic expectations.

 Figure 4: Effect sizes in animal studies versus human trials. Animals show 72-85% effects; humans show 12-48% effects. This gap explains why users often feel disappointed despite compelling animal research.

Dosage Matters More Than You'd Think

Here's something people often overlook: the dose used in research varied significantly, and those variations produced very different results.

In one study examining SSRIs and sexual dysfunction, women taking 1.5 grams of maca daily saw no significant improvement. Women taking 3.0 grams daily saw significant improvement.²⁶ Same supplement, same condition—but dose determined whether it worked.

Men with erectile dysfunction benefited from 2.4 grams daily.²⁷ Men with low testosterone symptoms took standardised doses in clinical trials. For fertility, effective doses were around 2 grams daily.²⁸

The pattern is clear: higher doses produce greater effects. The minimum effective dose appears to be around 1.5 to 2.0 grams daily, but 2.5 to 3.0 grams appears to be the optimal range based on clinical evidence. Most studied populations used 2.0 to 3.0 grams as the standard range, and studies lasting 8 to 12 weeks showed better results than shorter trials.

 Figure 5: Effectiveness increases with dosage. At 1.5g daily, maca showed no benefit for SSRI sexual dysfunction. At 3.0g daily, the same supplement produced significant improvement.

If you're considering maca, check the label. If it's recommending sub-therapeutic doses (under 1.5 grams), you're unlikely to see results. If it's recommending 2.5 to 3.0 grams and you commit to using it for at least 8 weeks, you have a better chance of noticing a benefit.

Safety Profile: One of the Best-Studied Supplements

This is where maca's record is genuinely excellent.

In clinical trials, serious adverse effects have been essentially non-existent. In a study of 56 adult men treated with maca at 1.5 to 3.0 grams daily for up to 12 weeks, adverse events were not reported.²⁹ In a larger trial of 175 adults given black or red maca extracts at 3 grams daily for 12 weeks, maca was well tolerated and showed zero serious adverse effects.³⁰

Across thousands of participants in clinical trials examining menopausal symptoms, sexual function, fertility, and energy, the safety record is spotless. No serious adverse events. No documented cases of liver injury. In fact, in a comprehensive review of drug-induced liver injury across approximately 50,000 liver transplants reported between 1990 and 2002, zero were attributed to maca.³¹ This matters because some herbal supplements do damage livers; maca isn't among them.

Gastrointestinal side effects? Not documented in clinical research. Even in a study specifically examining gastric effects in patients with functional dyspepsia (stomach problems), maca didn't produce significant changes to the stomach lining.³²

One historical note: a 90-day safety study documented a moderate diastolic blood pressure increase in volunteers taking 0.6 grams daily, though this effect was reversible with additional supplementation.³³ If you have blood pressure concerns, it's worth mentioning to your doctor, but this is a minor finding in an otherwise excellent safety record.

Hormone Concerns

Because maca affects hormone balance in menopausal women, some people worry it might be problematic for hormone-sensitive conditions. Here's what the research shows: maca doesn't have direct androgenic activity, so it shouldn't affect hormone-sensitive cancers the way actual hormone therapy would.³⁴ However, out of an abundance of caution, if you have a history of hormone-sensitive cancers (breast, ovarian, prostate, uterine), discuss maca with your doctor before use. The evidence suggests risk is low, but the conversation is worth having.

Special Populations and Contraindications

Pregnancy and breastfeeding: Limited safety data exist in published clinical trials. Medical consensus is that pregnant and breastfeeding women should discuss maca use with their healthcare provider before taking it—not because it's known to be unsafe, but because it hasn't been adequately studied in these populations.

People taking SSRIs: Good news. Maca is safe with SSRIs. In fact, it was studied precisely for managing SSRI-induced sexual dysfunction and was well tolerated in combination.

Quality concerns: Standardisation of maca products is an important gap. Products vary in their concentration of active compounds. In some regions (particularly areas influenced by mining activity in Peru), soil can accumulate heavy metals. Reputable manufacturers test for this, so purchase from established suppliers with third-party testing when possible. Choose standardised extracts when you can rather than raw powder.

 Figure 6: Safety assessment across adverse event categories. Maca shows essentially zero serious adverse events across thousands of participants in clinical trials.

Practical Guidance: Should You Try Maca?

The answer depends on what you're using it for and what your realistic expectations are.

For Menopausal Symptoms

• Evidence level: Good. Four randomised controlled trials all showed positive results
• Expected benefit: 74-87% see significant relief; 55% reduction in symptom scores
• Typical dose: 2-3 grams daily of pre-gelatinised maca
• Timeline: Benefits typically appear within weeks to 1-2 months
• Safety: Excellent. No serious adverse effects
• Bottom line: Maca has the strongest research evidence for this use. If you're dealing with hot flushes, night sweats, mood changes, or sexual issues related to menopause, maca is worth considering as a natural alternative to HRT

For Erectile Dysfunction (Mild)

• Evidence level: Moderate
• Expected benefit: Approximately 3 times greater improvement than placebo
• Dose: 2.4 grams per day
• Timeline: 12 weeks
• Bottom line: You'll likely see benefit, but maca shouldn't be your only approach. Address underlying causes (cardiovascular health, stress, relationship factors) alongside supplementation

For Sexual Dysfunction from Antidepressants

• Evidence level: Moderate
• Expected benefit: Significant improvement in sexual dysfunction scores
• Dose: 3.0 grams per day (critical: lower doses don't work)
• Timeline: 12 weeks
• Bottom line: This is an evidence-supported approach if SSRI sexual side effects are affecting your quality of life. It means you don't need to change your antidepressant

For Low Testosterone Symptoms

• Evidence level: Moderate
• Expected benefit: Sexual function improvement without direct hormone activity
• Bottom line: May be worth trying as an alternative to testosterone replacement if that's not appropriate for your situation

For Improving Fertility (Male Factor)

• Evidence level: Limited to moderate
• Expected benefit: May improve sperm concentration, but effects on other parameters are inconsistent
• Dose: 2 grams per day
• Timeline: 12 weeks
• Bottom line: Shouldn't replace standard fertility evaluation and treatment, but may work as an adjunct approach

For General Energy

• Evidence level: Limited to moderate
• Expected benefit: Modest and variable between individuals
• Dose: 3 grams per day (red maca possibly more effective than black)
• Timeline: Give 4-12 weeks to assess your personal response
• Reality check: Human evidence is more modest than animal research promises. Be patient and realistic

For Athletic Performance

• Evidence level: Limited to weak
• Expected benefit: Modest and sport-dependent. Endurance activities may benefit more than strength/power activities
• Dose: 2.0-2.5 grams per day
• Timeline: 8-12 weeks (not 2 weeks)
• Bottom line: Low risk to try, but don't expect dramatic improvements. Maca is a mild supplement, not a performance-enhancing drug

Further Reading

Understanding Hormonal Health

• Menopausal Symptoms and Hormone Balance
• Understanding the Menopause Transition

Sexual Function and Health

• Sexual Dysfunction: Causes and Treatment
• SSRI-Induced Sexual Dysfunction

Male Fertility and Semen Quality

• Male Infertility: Evaluation and Treatment
• Understanding Semen Analysis

Athletic Performance and Endurance

• Supplement Use in Athletes
• Energy Metabolism During Exercise

Herbal Supplements and Safety

• Safety of Herbal Supplements
• Supplement Quality and Standardisation