Maca root for libido and energy: what the evidence actually shows

Why maca keeps trending

Maca (Lepidium meyenii) is a root that grows high in the Peruvian Andes, dried and ground into a powder that people take at roughly 1.5 to 3 grams a day. It has been a food and folk remedy for centuries, and in the last decade it has become a fixture of the supplement aisle and the wellness feed, sold for libido, energy, mood, fertility, and menopause symptoms all at once. That is a lot of promises for one root, and the honest move is to separate the claim that has real support from the ones riding its coattails.

Here is the through-line for the whole piece: maca’s evidence is best for sexual desire, weaker for energy and mood, and actively misleading when it’s framed as a hormone booster. The most useful thing to understand up front is that maca does not behave like testosterone, estrogen, or anything that pushes on those hormones — a point we’ll come back to because it reshapes how you should read every other claim. For the rest of the field making similar promises, our sex & hormones hub grades each one on the same honest scale.

The strongest claim: sexual desire

Of everything maca is sold for, libido is the claim with the most behind it — though “the most” here is a low bar worth describing precisely. The cleanest single trial comes from Gonzales and colleagues, who gave healthy adult men either 1,500 mg, 3,000 mg, or placebo over 12 weeks. An improvement in self-reported sexual desire showed up from about week 8 onward in the maca groups versus placebo.² Notably, the researchers checked whether that desire bump was just better mood in disguise — and found the effect was independent of depression and anxiety scores, and independent of testosterone.²

Zoom out to the whole evidence base and the picture stays directionally positive but gets blurrier. The 2010 systematic review by Shin and colleagues pooled the four randomized trials that existed at the time — just 131 participants in total — and found that two suggested a real benefit on sexual function, one found nothing in healthy cyclists, and one found a benefit in men with mild erectile dysfunction.¹ Their verdict is the one to anchor on: the trials “provide limited evidence for the effectiveness of maca in the improvement of sexual function,” but the number of trials, the total sample size, and the methodological quality were “too limited to draw firm conclusions.”¹ That is why I grade the libido claim an EMERGING: the signal is consistent and points one way, but it is built on a handful of small, short, methodologically thin studies, not a settled literature.

Maca’s libido evidence isn’t strong — it’s consistent. Several small trials nudge the same direction, which is encouraging, and a long way from proven.

The honesty point: maca is non-hormonal

This is the part the “natural testosterone booster” marketing depends on you not knowing. When researchers have actually measured the hormones, maca does not move them. In a dedicated study of reproductive hormones in healthy men, Gonzales and colleagues reported plainly that “treatment with Maca does not affect serum reproductive hormone levels” — testosterone and estradiol were unchanged across the trial.³ The same team’s desire trial reached the matching conclusion from the other side: the desire effect appeared even though testosterone and estradiol stayed flat.²

So whatever signal maca pulls on desire, it is not the androgen signal. This matters in two directions. First, it kills the “T booster” framing outright — a product that demonstrably leaves your testosterone unchanged is not boosting your testosterone, and I grade both “maca works by raising testosterone or estrogen” and “maca is a proven natural testosterone booster” a flat HYPE. Second, it’s genuinely reassuring for anyone wary of a supplement quietly shifting their hormones: the leading hypotheses for maca’s effect point elsewhere, toward neurotransmitter and central pathways rather than the endocrine axis, though the actual mechanism remains unproven. If your real goal is moving testosterone, the honest read on the popular contenders is in our coverage of Tongkat Ali’s trial data and zinc’s deficiency-versus-booster split — not here.

Energy and mood: a thinner signal

Energy and mood are where maca’s marketing gets loudest and its evidence gets quietest. The data that exists is mostly small, subjective, and concentrated in one population. The clearest mood signal comes from Brooks and colleagues, who ran a randomized, double-blind, placebo-controlled crossover trial in 14 postmenopausal women, giving 3.5 g/day of maca for six weeks against placebo. Maca reduced anxiety and depression scores and lowered measures of sexual dysfunction — and, consistent with everything above, the authors specifically reported these benefits were “not related to estrogen or androgen content.”⁴

That is a real, well-designed result, but read its size and scope before you generalize. Fourteen women, six weeks, one menopausal stage. Per the way female-specific responses work, the postmenopausal context is doing real work here: this is a low-estrogen state, and the women in this trial were past the cyclical swings of prolactin, cortisol, estrogen, and progesterone that complicate results in cycling women — so this finding should be read as specific to postmenopausal women, not transplanted onto every user. On the broader “maca for energy” claim, the controlled evidence is even thinner and leans heavily on subjective self-report. That combination — one good small trial in a narrow group, plus a lot of soft energy data — is why I grade the energy-and-mood claim a WEAK: there is a signal, but it is small, narrow, and not yet replicated at scale.

The SSRI question

One of the more interesting niche uses is for sexual dysfunction caused by antidepressants — a common, frustrating side effect of SSRIs (selective serotonin reuptake inhibitors, the most widely prescribed antidepressant class). Dording and colleagues ran a double-blind, randomized dose-finding pilot in 20 people whose depression had remitted on an antidepressant but who were left with SSRI-induced sexual dysfunction, comparing low-dose maca (1.5 g/day) against high-dose (3.0 g/day).⁵ The signal favored the higher dose, with improvement on standardized sexual-function scales and good tolerability.⁵

It’s a promising, sensible result — but keep the frame honest. This was a pilot of 20 people, designed mainly to find a dose rather than to prove efficacy, and it has not been followed by a large confirmatory trial. So I grade “maca helps SSRI-induced sexual dysfunction” an EMERGING: a real, dose-dependent hint worth knowing if you’re weighing low-risk add-ons with a prescriber, not a settled treatment. If you want a sense of where your own baseline sits before adding anything, our lab-range interpreter is a better first move than stacking supplements blind.

The caveats that matter

Beyond the grades, three practical caveats shape how much weight to put on any of this. First, the trials are heterogeneous in a way that quietly undermines pooling: maca comes in different colors (yellow, red, black) that may not be biologically interchangeable, and studies have used different doses, durations, and preparations. When you average across that variety, you blur real differences, and the modest pooled effect could be hiding both stronger and weaker truths.

Second, the studies are short — six to twelve weeks is typical — so the long-term picture is essentially unstudied. Third, on safety: maca is a food crop with a good tolerability record, which is the main reason it’s a low-risk thing to try. The one mechanistic flag worth naming is that maca, like other plants in the brassica family, contains goitrogens — compounds that can interfere with thyroid function in large amounts — so anyone with existing thyroid concerns should be cautious with high intakes and loop in a clinician. None of this makes maca dangerous; it makes the “more is always better” instinct a poor fit for a supplement whose proven benefits are modest to begin with.

The bottom line

Strip away the stacked promises and maca’s evidence sorts cleanly. Its best-supported claim is sexual desire, where several small trials and a 2010 systematic review point the same direction — encouraging, consistent, and openly described by the reviewers as too thin for firm conclusions.¹² Crucially, it does this without touching testosterone or estrogen, which both debunks the “natural T booster” pitch and reassures anyone worried about a hormonal side door.²³

The energy and mood claims are real but narrower — the strongest sits in a 14-woman postmenopausal trial — and the SSRI use is a promising pilot, not a proven therapy.⁴⁵ So the verdict isn’t “maca works” or “maca is a scam.” It’s narrower and more useful: a low-risk, non-hormonal option with genuine but modest support for desire specifically, and thinner evidence everywhere else. If you try it, try it for the right reason, give it eight weeks, and don’t expect it to move a number on a blood panel.

What we still don’t know

Trial size and quality. There is still no large, modern, high-quality RCT that settles maca’s libido effect. The strongest existing data are small and methodologically limited, which is exactly why even the best claim sits at EMERGING rather than MODERATE.

The mechanism. If maca improves desire without touching sex hormones, how it does so is genuinely unresolved. The leading guesses point toward central, non-endocrine pathways, but none is confirmed — and until it is, the effect remains a finding without an explanation.

The variety and the population gaps. Whether yellow, red, and black maca differ in effect is unsettled, and dedicated trials in cycling premenopausal women, in men with low baseline desire, and over long durations are largely missing. The postmenopausal mood signal is the cleanest piece we have — and it rests on fourteen women for six weeks.