Maca
Lepidium meyenii
Andean root with modest, inconsistent libido evidence.
Evidence tier
Preliminary
Research weight
Citations
15 verified / 15
Classification
Adaptogen
❝
What the evidence says. Early or small human trials; promising but not yet conclusive.
What is Maca?
Maca (Lepidium meyenii) is an adaptogen used for possible improved sexual desire. NutriDex grades the human evidence as Preliminary. Maca is a Peruvian root food traditionally used for energy and fertility. Several small RCTs suggest a modest improvement in sexual desire in men and women and some benefit for menopausal symptoms and semen quality, while at least one trial found no effect. Systematic reviews conclude the evidence is limited by small, low-quality studies — promising but not definitive.
Purported Benefits
✓Possible improved sexual desire
✓Possible menopausal-symptom & mood support
✓Possible sperm-quality support
Evidence by outcome
The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.
| Outcome | Evidence | Effect | Studies |
|---|---|---|---|
| Sexual desire / libidoMultiple small RCTs and reviews suggest improved desire, but the 2010 systematic review flags small, low-quality trials. | Preliminary | ↑ benefit · small | 3 |
| Sperm concentration / fertilityMeta-analysis of 5 RCTs (~244 men) found no significant effect on sperm concentration; one RCT showed only non-significant trends. | Moderate | — no effect · negligible | 3 |
| Menopausal symptoms & moodSmall crossover RCTs reduced Greene/Kupperman and depression scores without hormonal change; systematic review notes methodologically weak trials. | Preliminary | ↑ benefit · small | 3 |
| Antioxidant status (GPx, SOD, MDA)One meta-analysis of 8 studies showed dose-dependent antioxidant improvements, but the pool mixes preclinical and clinical data. | Preliminary | ↑ benefit · moderate | 1 |
Dosing & Compounds
Typical Dose
1.5–3 g/day of dried root powder (as used in trials).
Active Compounds
Safety & Cautions
Generally well tolerated as a food. Possible mild GI effects. Caution in hormone-sensitive conditions due to limited data. Educational only — always check with your doctor or pharmacist before combining Maca with any medicine.
Key Studies ★ 15 studies
meta-analysis
Lee 2023 (systematic review & meta-analysis)
✓ Full text
Review of RCTs for erectile dysfunction found only 2 eligible trials suggesting a positive effect of maca on erectile function in mild ED, but overall evidence was limited and low-quality.
meta-analysis
Cellular oxidative stress review 2024 (systematic review & meta-analysis)
✓ PubMed
Meta-analysis of 8 studies found maca (mainly macamides) dose-dependently improved antioxidant markers (glutathione peroxidase SMD 0.96, SOD 0.68) and lowered malondialdehyde (SMD -0.53).
Systematic review
Carrasco Front Pharmacol 2024
✓ PubMed
Comprehensive review concludes clinical studies indicate improved sexual desire, erectile function, and subjective wellbeing in men, plus alleviation of menopausal symptoms in women, though mechanisms remain unclear.
meta-analysis
Ki 2022 (systematic review & meta-analysis)
✓ PubMed
Pooled analysis of 5 RCTs (~244 men) found no significant effect of maca on sperm concentration (WMD 2.22, 95% CI -2.94 to 7.37, p=0.4); effects on semen quality remain unclear.
Meta-analysis
Lee Front Pharmacol 2022
✓ Full text
Meta-analysis of 5 RCTs found maca failed to significantly increase sperm concentration versus placebo (weighted mean difference 2.22, 95% CI -2.94 to 7.37, p=0.4); effects on semen quality were unclear.
Systematic review
Shin 2010 (systematic review)
✓ PubMed
Limited evidence for improved sexual desire; trials small and low-quality.
systematic review
Brooks/Lee 2011 (Maturitas systematic review)
✓ PubMed
Systematic review of 4 RCTs found favorable effects of maca on menopausal symptoms (Kupperman Index / Greene Climacteric Score), but concluded evidence was limited by small, methodologically weak trials.
RCT
Shin 2023 (RCT)
✓ PubMed
In 80 men with late-onset hypogonadism symptoms, 12 weeks of 6 g/day maca significantly improved AMS, IIEF and IPSS scores and reduced ADAM-positive rate versus placebo (p<0.05).
RCT
Gonzales-Arimborgo 2021 (RCT)
✓ PubMed
In 50 infertile men, 16 weeks of maca produced only non-significant trends in sperm concentration (40% rise vs 76% with placebo); evidence insufficient to confirm a fertility benefit.
randomized controlled trial
Stojanovska 2015 (Climacteric RCT)
✓ PubMed
In a randomized double-blind crossover pilot of 29 postmenopausal Chinese women, 3.3 g/day maca for 6 weeks significantly reduced diastolic blood pressure and depression scores versus placebo, without hormonal changes.
RCT
Dording 2015
✓ PubMed
12-week double-blind placebo-controlled RCT (n=45 women, maca 3.0 g/day) for antidepressant (SSRI/SNRI)-induced sexual dysfunction: remission rates were higher for maca than placebo on ASEX (9.5% vs 4.8%) and MGH-SFQ (score <=12: 30.0% vs 20.0%), with benefit concentrated in postmenopausal women; maca was well tolerated. A small/preliminary positive signal.
authoritative body / drug-safety database
LiverTox 2020 (NIH/NIDDK)
✓ Full text
NIH LiverTox classifies maca as an unlikely cause of clinically apparent liver injury (likelihood category E); side effects are uncommon and mild (mainly GI symptoms and headache), with one isolated 2017 case of jaundice from maca medicinal liquor.
Clinical trial
Cyclist RCT
✓ PubMed
No effect in one trial — results inconsistent across studies.
RCT
Brooks 2008
✓ PubMed
Randomized double-blind placebo-controlled crossover trial (n=14 postmenopausal women, 3.5 g/day maca x6 wk): significant reduction in Greene Climacteric Scale psychological symptoms (anxiety and depression subscales) and in sexual dysfunction vs placebo and baseline (P<0.05), with no change in estradiol, FSH, LH, or SHBG, indicating effects independent of estrogenic/androgenic activity.
Review
Menopause / semen reviews
✓ PubMed
Some RCTs suggest benefits for libido, menopausal symptoms and sperm quality.