Maca Root and Libido in Men: What the Evidence Actually Shows

Tom of P-Town Health — Provincetown, MA

Maca (Lepidium meyenii) is a cruciferous root vegetable grown at high altitude in the Peruvian Andes, where it's been used as both a food staple and a traditional remedy for fertility and vitality for centuries. It's since become one of the most widely marketed "natural libido" supplements in the U.S. — but how much of that reputation holds up under actual clinical scrutiny? Below is a plain look at the human research, what it does and doesn't show, and the safety considerations worth knowing before trying it.

The core evidence: sexual desire, not testosterone

The most frequently cited trial in this space is a 12-week, double-blind, placebo-controlled study of 57 healthy men aged 21–56, who were randomized to 1,500 mg or 3,000 mg of gelatinized maca daily or placebo. Men in the maca groups reported improved sexual desire starting around week 8, and the effect held through week 12. Notably, the researchers also tracked mood (via depression and anxiety scales) and serum testosterone and estradiol, and found no significant differences between groups on any of those measures — meaning the improvement in desire couldn't be explained by mood changes or a hormonal shift. The authors concluded maca had an independent effect on libido that didn't run through the testosterone pathway (Gonzales et al., 2002).

This is an important and somewhat counterintuitive finding: maca does not appear to work like a testosterone booster.A separate hormone-focused trial from the same research group, using an even larger sample, again found no significant between-group differences in LH, FSH, prolactin, or sex steroid levels after 12 weeks of maca — reinforcing that whatever maca is doing for desire, it isn't via the hypothalamic-pituitary-gonadal axis in any measurable way (Gonzales et al., 2003).

Erectile function: thinner, more mixed evidence

Desire and erectile function are not the same thing, and the data split accordingly. A randomized, double-blind trial in men with mild erectile dysfunction found that a maca extract improved self-reported well-being and sexual performance scores compared to placebo (Zenico et al., 2009). This is one of the few trials to look specifically at an ED population rather than healthy volunteers, and the improvement, while real, was modest — it was a subjective-outcome study, not one built around validated erectile-function instruments or objective measures.

Other open-label work in men with mild ED has reported self-rated improvement, but without a placebo control group, which limits how much weight that evidence can carry on its own.

Bottom line on ED specifically: there's a reasonable signal that maca may help mild erectile difficulties, but the evidence base is much thinner than for libido/desire, and no trial has ever compared maca head-to-head against an approved ED medication like sildenafil or tadalafil. Maca is not a substitute for standard ED evaluation or treatment, especially in men where ED reflects a vascular, neurologic, or cardiac issue that warrants its own workup.

What about semen quality and fertility?

Small pilot trials have looked at semen parameters (concentration, motility) in healthy men taking maca, with some suggesting modest increases in sperm concentration without significant hormonal changes. These studies tend to be small (13–20 participants) and short in duration, so they should be read as preliminary rather than definitive. If fertility is the primary concern, maca is not a replacement for a standard fertility workup.

Proposed mechanism

Since maca doesn't appear to shift sex hormone levels in a meaningful way, researchers have proposed a few alternative explanations for its effect on desire:

• Nutrient density — maca contains amino acids, minerals (notably zinc and iron), and plant sterols that may support general energy and vascular health.
• Adaptogenic activity — maca is often classified as an adaptogen, with proposed effects on the body's stress response that could indirectly support sexual interest and performance.
• Non-hormonal central effects — some researchers speculate maca may act on mood- or arousal-related signaling in the central nervous system, independent of the endocrine axis, though this hasn't been well characterized in humans.

None of these mechanisms are firmly established — they're plausible explanations for an effect that's been observed clinically but not yet fully explained biologically.

Dosing used in trials

Across the human studies above, doses generally ranged from 1,500–3,000 mg per day of gelatinized maca root, taken for at least 6–8 weeks before an effect on desire was detectable. Trials using lower single doses or shorter durations have generally not shown the same benefit, suggesting maca is not a same-day or "as-needed" product — it works, if it works, as a cumulative daily supplement.

Safety and tolerability

Across trials, maca has generally been well tolerated, with mild GI upset (nausea, stomach cramping) the most commonly reported side effect and no serious adverse events documented in the human trial literature. That said, a few caveats are worth flagging clinically:

• Thyroid function: Maca is a cruciferous plant and contains goitrogenic compounds. While this hasn't translated into documented clinical thyroid problems in the trials above, anyone with a known thyroid disorder should discuss maca with their provider before starting it.
• Hormone-sensitive conditions: Although maca hasn't been shown to raise sex hormone levels in trials, data specifically in men with hormone-sensitive cancers or conditions is lacking. Caution and a conversation with your care team is reasonable here.
• Drug interactions: Maca hasn't been well studied in combination with SSRIs/SNRIs, hormone therapies, or other prescription medications. If you're on any of these, tell your prescriber before adding maca.
• Long-term safety: All of the trials above ran 12 weeks or less. There's no good long-term human safety data beyond that window.
• Supplement regulation: Maca products are regulated as dietary supplements, not drugs. The FDA does not evaluate them for safety or efficacy before they reach the market, and product quality/potency can vary significantly by manufacturer. Sourcing matters.
• Not a substitute for medical evaluation: New or worsening erectile difficulty, especially in men over 40 or with cardiovascular risk factors, can be an early marker of vascular disease and should be evaluated by a clinician rather than self-treated.

The honest summary

The best human evidence supports a modest, reproducible improvement in sexual desire in men taking 1,500–3,000 mg of maca daily for 8–12 weeks, occurring independently of any measurable change in testosterone. The evidence for improving erectile function specifically is real but considerably weaker and less consistent. Maca is not a hormonal therapy, not a fast-acting aphrodisiac, and not a replacement for evaluating the underlying causes of low libido or ED — but for men looking for a reasonably well-tolerated adjunct with some legitimate clinical trial support behind it, it's one of the more evidence-backed options in a supplement category that's mostly noise.

As always, talk with your provider before starting any new supplement, particularly if you have a thyroid condition, hormone-sensitive condition, or are on other medications. If you'd like to try it please order from a reputable supplier like our dispensary 

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1. Gonzales GF, Córdova A, Vega K, Chung A, Villena A, Góñez C, Castillo S. Effect of Lepidium meyenii (MACA) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men. Andrologia. 2002;34(6):367–372.
2. Gonzales GF, et al. Effect of Lepidium meyenii (Maca) on serum reproductive hormone levels in adult healthy men. (Cochrane CENTRAL indexed trial record, 2003.)
3. Zenico T, Cicero AF, Valmorri L, Mercuriali M, Bercovich E. Subjective effects of Lepidium meyenii (Maca) extract on well-being and sexual performance in patients with mild erectile dysfunction: a randomised, double-blind clinical trial. Andrologia. 2009;41(2):95–99.
4. Gonzales GF, Nieto J, Rubio J, Gasco M. Effect of black maca (Lepidium meyenii) on semen parameters and hormonal levels in healthy adult men (pilot RCT).
5. Shin D, et al. World Journal of Men's Health. 2023;41(3):692–700.
6. Systematic review: A comprehensive review of the effects of maca (Lepidium meyenii) on sexual health outcomes. Frontiers in Pharmacology. 2024.
7. Systematic review: Maca (L. meyenii) for improving sexual function. BMC Complementary and Alternative Medicine (Cochrane DARE-indexed systematic review, 2010).

This post is for educational purposes and reflects a review of the available clinical trial literature as of 2026. It is not a substitute for individualized medical advice. Talk to your provider about whether maca is appropriate for you.