Maca: The Honest Evidence on Libido and Testosterone

Does Maca Work? The Evidence, Outcome by Outcome

Does maca work? The verdict, outcome by outcome

Maca is sold to you for at least six different reasons. The evidence behind each one is not equal. Here's the honest grade for every claim, before the detail.

Sexual desire: modest support, and it's the strongest lane maca has

The anchor trial gave men 1,500 mg or 3,000 mg of maca a day for 12 weeks. Self-reported desire improved from week 8 (PMID 12472620). Testosterone and estradiol didn't move. The effect held after adjusting for depression and anxiety scores.

A separate review found that phytoestrogens isolated from maca, alongside fennel and maritime pine bark, significantly improved sexual function in menopausal women, while soy, red clover, genistein and flaxseed did not (PMID 30156931). A review of herbal treatments for erectile dysfunction found maca contributed one trial of 50 people, called "very preliminary" (PMID 29633089).

Don't let anyone oversell this to you. A systematic review searched 17 databases and found only 4 trials that qualified (PMID 20691074). One of those four found no effect in healthy cyclists. The reviewers called the evidence limited. Desire is also a self-report measure in every trial cited here, not a lab test.

Antidepressant-induced sexual dysfunction: preliminary, but the effect size is real

This is a narrow claim about a specific side effect. Twenty remitted, depressed outpatients with SSRI-related sexual dysfunction were randomized to 1.5 g or 3.0 g of maca a day. Only 10 completed the trial. On 3.0 g/day, both sexual-function measures improved. On 1.5 g/day, neither did (PMID 18801111).

A larger follow-up gave 45 women 3.0 g/day for 12 weeks. Remission rates were higher on maca, but the gap was small: 9.5% vs 4.8% on one measure, 30.0% vs 20.0% on another (PMID 25954318). Read the actual percentages before treating "improved sexual function" as a strong claim. The benefit was tied to postmenopausal status specifically.

Menopausal symptoms: favourable trials, but the review calls its own evidence thin

A systematic review found 4 trials, and all four favoured maca on standard menopause symptom scores (PMID 21840656). That same review states, in its own words, that maca's safety "has not been proved yet."

A 6-week-per-arm crossover trial in 29 postmenopausal women found no change in estradiol, FSH, TSH, SHBG, glucose, lipids or cytokines at 3.3 g/day. It did find lower diastolic blood pressure and lower depression scores (PMID 24931003). Both are pilot findings in a small sample. A separate minireview lists maca among extracts that reduce hot flushes (PMID 24314619).

Testosterone: not supported, and the shelf claims it constantly

Say it flatly: maca does not raise testosterone. The anchor trial measured it directly at 1,500 and 3,000 mg/day and found no difference from placebo (PMID 12472620). The menopause crossover trial measured estradiol, FSH, TSH and SHBG and found none of them moved either (PMID 24931003).

A 2024 systematic review of testosterone-boosting supplements concluded most ingredients in this category fail to raise total testosterone. Maca was not named among the exceptions (PMID 37697053). Three independent studies point the same direction. If a maca product markets itself as a testosterone booster, the research on this page does not back that claim.

Fertility and semen quality: the pooled result is null

A 2022 meta-analysis pooled 5 randomized trials on maca and semen quality (PMID 36110519). For sperm concentration, the pooled result was null: a weighted mean difference of 2.22, 95% confidence interval −2.94 to 7.37, p=0.4. The reviewers called the evidence unclear and the trial pool too small for firm conclusions.

Don't soften this one. Maca is sold heavily for fertility. The best pooled data available does not support that use.

Energy and physical performance: mostly animal data

A 2024 review pooled 16 studies on maca and physical performance (PMID 39796542). Most of the pooled outcomes are rodent tests: forced swimming, rota-rod, grip strength and blood lactate. That is not human performance evidence, and we won't present it that way.

The one human performance trial gave 8 trained male cyclists maca for 14 days. Their 40 km time trial improved against their own baseline, but it did not beat placebo (PMID 19781622). Better than doing nothing is not the same as better than a sugar pill.

The stronger human signal is mood, not power output. A 175-person, 12-week trial of spray-dried maca found improvements in mood, energy and quality of life, with no serious adverse effects (PMID 27548190). Part of that group lived at high altitude, which limits how far the result generalizes. Red maca did better for mood and energy; black maca lowered blood glucose.

So who is this reasonable for?

• If you want the best-supported effect, it's on self-reported sexual desire, and it's modest — not a guaranteed result.
• Skip it if you're buying it as a testosterone booster or fertility aid. The trials cited here don't support either use.
• If you try it, take 3,000 mg/day, the dose the positive trials used — see the dosage guide for what that means in capsules.
• Trials only ran 6 to 12 weeks. There is no long-term evidence, positive or negative, past that window.

Common questions