Common Names
- Maca-maca
- Maino
- Ayak chichira
- Ayak willku
For Patients & Caregivers
How It Works
Maca may increase sexual function, but more studies are needed.
Maca is an herbaceous plant related to the cabbage family and is a nutritional staple in Peru. It is used in traditional medicine to improve stamina and sexual functioning. Lab experiments suggest various properties and benefits, but only a few studies have been conducted in humans. Some of these studies suggest possible benefit to improve sexual dysfunction or menopausal symptoms, but more studies are needed to determine safety and effectiveness.
Maca may affect blood hormone levels, so patients should discuss any use of this supplement with their physician.
Purported Uses
Do Not Take If
Side Effects
Unverified possible reactions include: altered menstrual cycles, moodiness, cramps, gastritis and insomnia
Case report
- Prolonged bleeding and high testosterone levels: In a woman in her thirties who took 1 tsp daily of maca powder to improve energy and libido. Bleeding began within a few weeks of this regimen and improved after she stopped taking maca. High testosterone levels also returned to normal 1 month after she stopped taking maca.
For Healthcare Professionals
Clinical Summary
Maca is a nutritionally valuable plant native to Peru that grows in harsh climates above 4,000 feet. It has been used traditionally to enhance fertility and sexual performance in both men and women and to relieve menopausal symptoms (1). In vitro, maca or its constituents have demonstrated antiviral (17), antioxidant (18), anti-inflammatory, analgesic, or neuroprotective (19) activities. Animal studies suggest maca may increase endurance (6), enhance sexual function (2) (5), and improve memory deficits (14). It also demonstrated antidepressant (20) and postmenopausal hormone-modulating (21) effects.
Only a few small trials have been conducted in humans. Maca consumption was associated with lower serum IL-6 levels and higher health status (22). In men, preliminary findings suggest supplementation may enhance subjective sexual well-being (11), but data are mixed on whether it can affect various parameters of semen quality (3) (4) (35). In women, several studies suggest maca improves both antidepressant- and menopause-induced sexual dysfunction (12) (24) (25) (26), although one small study showed neither hormonal nor immunological effects (27). In addition, systematic reviews have deemed evidence for improving sexual dysfunction (13) (28) (29) or menopausal symptoms (15) to be limited. Another review found maca is not an effective anti-aging agent (16).
A case report showed maca may interfere with testosterone immunoassays (30). Although it is unclear the extent to which maca may affect blood hormone levels, patients should discuss any use of this supplement with their physician.
Mechanism of Action
Maca contains glucosinolates, mostly benzylglucosinolate, along with hydroxy or methoxylated benzyl derivatives and tryptophan-derived compounds, and depending on the phenotype (red, yellow, purple or black) may be associated with different biological effects (31).
In vitro, both methanolic and aqueous extracts of maca exhibit estrogenic activity (10). A methanol maca extract demonstrated antiviral activity against Flu-A and Flu-B viruses (17). An isolated N‑alkylamide from maca root exerted cannabimimetic actions (32). Maca polysaccharides demonstrated radical scavenging activity (18). Macamides, normally not present in fresh plants but introduced during traditional drying practices (31), are fatty acid amide hydrolase inhibitors that modulate release of neurotransmitters (19). Antidepressant-like effects were associated with activation of both noradrenergic and dopaminergic systems and attenuation of oxidative stress (20).
In animal models, maca powder enhanced serum luteinizing hormone (LH) levels in female rats during the proestrus LH surge in a dose-dependent manner, suggesting it may enhance fertility (33). In postmenopausal models, maca modulates hormone levels particularly by decreasing follicle-stimulating hormone (FSH) levels (21).
In humans, although maca does not affect serum levels of LH, FSH, prolactin, testosterone, or estradiol in men (4) (9), it appears to modulate some hormone levels in women in some studies (24) (26) but not others (25) (27). Increased LH and decreased FSH that corresponded with improved sexual functioning in postmenopausal women are potentially attributed to a negative feedback loop, resulting in increased androgen production (24) (26). It may also exert androgenic effects at the testosterone receptor on target organs without affecting testosterone or gonadotrophin levels (24) (30). At the same time, the benefits of maca for antidepressant-induced sexual dysfunction in women may be more a function of advancing age rather than menopausal status, as there was no correlation with estrogen levels (24).
Adverse Reactions
Subjective reports of altered menstrual cycles, moodiness, cramps, gastritis, and insomnia (34). Flu-like symptoms and vomiting were reported in one study, but it is unclear if these were caused by maca (24).
Case report
Prolonged intermenstrual bleeding, elevated testosterone: In a woman in her thirties who ingested maca powder 1 tsp daily to improve energy levels and libido (30).
Herb Lab Interactions
Maca may interfere with testosterone immunoassays (30).