Maca
Maca (Lepidium meyenii), a Peruvian root vegetable from the Andes, is traditionally used to enhance fertility, sexual function, energy, and menopausal symptom relief. Available in black, red, or yellow varieties, it contains glucosinolates, flavonoids, and macamides, offering antioxidant and anti-inflammatory benefits. Clinical trials suggest maca may improve libido, sperm quality, menopausal symptoms, and psychological well-being without altering hormone levels.
Benefits
Improved Sexual Function and Libido
Enhances libido and sexual performance in men with mild erectile dysfunction (2.4 g/day, 12 weeks; significant improvement in IIEF-5 scores, p < 0.001). Reduces SSRI-induced sexual dysfunction in women (3.0 g/day, 12 weeks; improved ASEX and MGH-SFQ scores, p < 0.05). Increases sexual desire in male athletes (2 g/day, 14 days; p = 0.03).
Enhanced Male Fertility
Improves sperm concentration, count, and motility in healthy men and those with infertility (2 g/day, 12 weeks; p < 0.05), without altering hormone levels (testosterone, LH, FSH).
Relief of Menopausal Symptoms
Reduces hot flushes, night sweats, depression, and anxiety in peri- and postmenopausal women (3–3.5 g/day, 6–12 weeks; p < 0.001 for Maca-GO®), independent of estrogen changes.
Improved Psychological Well-Being
Decreases depression and anxiety in postmenopausal women (3.5 g/day, 6 weeks; p < 0.05) and in overweight/obese individuals (33.2% anxiety reduction, 29.4% depression reduction, 8 weeks).
Enhanced Physical Performance
Modestly improves cycling performance in trained male athletes (2 g/day, 14 days; 1.84% reduction in 40 km time trial, p = 0.01).
Support for Late-Onset Hypogonadism
Improves sexual function and urination symptoms in men over 40 (12 weeks; significant improvements in IIEF-5 and IPSS scores, p < 0.05).
Mechanism of Action
Antioxidant and Anti-Inflammatory Effects
Glucosinolates and flavonoids scavenge free radicals and reduce oxidative stress, which may improve sperm quality, menopausal symptoms, and general cellular health. Glucosinolates (e.g., benzyl glucosinolate) break down into isothiocyanates, which modulate inflammatory pathways like NF-κB, reducing pro-inflammatory cytokines (e.g., IL-6).
Neuroendocrine Modulation (Adaptogenic Properties)
Unique fatty acid derivatives (e.g., N-benzyl-palmitamide) interact with the hypothalamic-pituitary-adrenal (HPA) axis, balancing stress responses and enhancing energy, mood, and libido. They may act as endocannabinoid-like compounds, influencing CB1 receptors to improve psychological well-being.
Spermatogenesis Support
Maca’s alkaloids and amino acids (e.g., arginine) support sperm production and motility, likely by protecting testicular tissue from oxidative damage and enhancing mitochondrial function in sperm cells.
Estrogenic Support in Menopause
While Maca lacks direct estrogenic activity, its metabolites (e.g., via glucosinolate breakdown) may modulate estrogen receptor signaling indirectly, reducing menopausal symptoms like hot flushes and night sweats.
Energy and Performance Enhancement
Polysaccharides and Sterols improve mitochondrial efficiency and glucose metabolism, enhancing physical endurance and reducing fatigue. Beta-sitosterol may support muscle recovery.
Clinical Trials
Maca for Mild Erectile Dysfunction (ED)
Study: A randomized, double-blind, placebo-controlled trial in Italy enrolled 50 Caucasian men with mild ED. Participants received 2.4 g/day maca dry extract or placebo for 12 weeks. Outcomes were assessed using the International Index of Erectile Function (IIEF-5) and Satisfaction Profile (SAT-P).
Findings: Both groups showed improved IIEF-5 scores (p < 0.05), but the maca group had a significantly greater increase (1.6 ± 1.1 vs. 0.5 ± 0.6, p < 0.001). Psychological performance-related SAT-P scores improved in both groups, with maca showing a higher improvement (+9 ± 6 vs. +6 ± 5, p < 0.05). Maca modestly enhanced subjective sexual well-being.
Link: https://pubmed.ncbi.nlm.nih.gov/19260845/
Maca for SSRI-Induced Sexual Dysfunction in Women
Study: A 12-week, double-blind, placebo-controlled trial at Massachusetts General Hospital enrolled 45 women (mean age 41.5 ± 12.5 years) with remitted depression and SSRI/SNRI-induced sexual dysfunction. Participants received 3.0 g/day maca root or placebo. Outcomes were measured using the Arizona Sexual Experience Scale (ASEX) and Massachusetts General Hospital Sexual Function Questionnaire (MGH-SFQ).
Findings: Both groups improved, but the maca group showed significant improvements in ASEX and MGH-SFQ scores, particularly in libido and sexual enjoyment. The effect was more pronounced at 3.0 g/day compared to a lower dose (1.5 g/day) in a parallel study, suggesting dose dependency.
Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4411442/
Maca for SSRI-Induced Sexual Dysfunction (Dose-Finding Study)
Study: A double-blind, randomized, pilot dose-finding study enrolled 20 remitted depressed outpatients (17 women, mean age 36 ± 13 years) with SSRI-induced sexual dysfunction. Participants received low-dose (1.5 g/day) or high-dose (3.0 g/day) maca or placebo for 12 weeks. Outcomes included ASEX and MGH-SFQ scores.
Findings: Both doses improved sexual function, with the high-dose group (3.0 g/day) showing greater improvements in libido and sexual function compared to the low-dose group and placebo. No effect on serum hormone levels (e.g., testosterone, estrogen) was observed.
Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6494060/
Maca for Menopausal Symptoms
Study: A systematic review included four randomized controlled trials (RCTs) assessing maca for menopausal symptoms in peri- and postmenopausal women, using the Kupperman Menopausal Index and Greene Climacteric Scale. Trials tested various maca preparations (e.g., Maca-GO®) vs. placebo for 6–12 weeks.
Findings: All RCTs showed favorable effects on menopausal symptoms (e.g., hot flushes, night sweats, depression). Maca-GO® trials reported significant reductions (p < 0.001) in symptoms, with an 84% success rate in postmenopausal women and 74–82% in perimenopausal women, alongside benefits for heart and bone health. Effects were not related to estrogen or androgen changes.
Link: https://pubmed.ncbi.nlm.nih.gov/21840656/
Study: A 12-week, double-blind, placebo-controlled trial in Peru enrolled men with infertility to assess 2 g/day maca on semen quality and hormone levels. Another study examined maca’s effect on sperm count and motility in healthy men.
Findings: Maca significantly improved sperm concentration (p < 0.05) but not motility compared to placebo. A separate study found increased semen volume, sperm count, and motility in healthy men after 12 weeks, without affecting serum testosterone, LH, FSH, or estradiol levels.
Link: https://pubmed.ncbi.nlm.nih.gov/34585449/
Maca for Physical Performance in Athletes
Study: A 14-day, placebo-controlled crossover study at Northumbria University enrolled 8 trained male cyclists receiving 2 g/day maca extract (5:1, equivalent to 10 g raw maca). The outcome was 40 km cycling time trial performance.
Findings: Maca improved cycling time (1.84% reduction, 57.62 ± 3.14 min to 56.56 ± 2.68 min, p = 0.01) compared to baseline, but not significantly vs. placebo (p > 0.05). Sexual desire also improved significantly (p = 0.03).
Link: https://pubmed.ncbi.nlm.nih.gov/19781622/
Maca for Late-Onset Hypogonadism
Study: A 12-week, randomized, double-blind, placebo-controlled trial in Korea enrolled 80 eugonadal men (aged >40 years) with late-onset hypogonadism symptoms. Participants received gelatinized maca tablets or placebo. Outcomes included IIEF-5, International Prostate Symptom Score (IPSS), and Aging Males’ Symptoms (AMS) scores.
Findings: The maca group showed significant improvements in IIEF-5 (sexual function) and IPSS (urination symptoms) at weeks 4 and 12 compared to placebo (p < 0.05). AMS scores improved, but only total scores were analyzed. No serious adverse events were reported.
Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10307657/
Maca for Psychological Symptoms in Postmenopausal Women
Study: A 6-week, double-blind, placebo-controlled trial enrolled 14 postmenopausal women receiving 3.5 g/day maca. Outcomes included psychological symptoms (depression, anxiety) and sexual dysfunction, measured via Greene Climacteric Scale.
Findings: Maca reduced depression and anxiety scores (p < 0.05) but showed non-significant reductions in menopausal symptoms (p = 0.07). No changes in estrogen or androgen levels were observed.
Link: https://pubmed.ncbi.nlm.nih.gov/18784609/
Potential Side Effects
Gastrointestinal Issues
Mild abdominal discomfort, bloating, or nausea. Noted in trials with doses of 2–3.5 g/day (e.g., menopausal women, 6–12 weeks). Incidence is low (<10% of participants).
Elevated Liver Enzymes
Slight increase in serum alanine aminotransferase (ALT). Observed in one study at 0.6 g/day for 90 days, but levels remained within normal ranges and were not clinically significant.
Increased Blood Pressure
Minor increase in diastolic blood pressure. Reported in the same study at 0.6 g/day for 90 days, but not replicated in other trials with higher doses (e.g., 2–3 g/day).
Headaches or Insomnia
Occasional reports of headaches or sleep disturbances. Anecdotal in some trials (e.g., athletes, 2 g/day) but not statistically significant or consistently reported.
Hormonal Effects (Rare)
Description: Mild symptoms like acne or irregular menstruation in women, possibly due to adaptogenic effects on the HPA axis. Rare case reports, not consistently observed in trials. No significant changes in serum testosterone, estrogen, FSH, or LH levels were found.