Maca: The Andean Root With More Stories Than Data
Maca (Lepidium meyenii) is an Andean root marketed as an aphrodisiac, fertility aid, and energy booster, but its clinical evidence is thinner and more equivocal than its reputation. The best signal is for sexual function: a 2010 review of four small RCTs suggested modest benefit in SSRI-induced and menopausal sexual dysfunction, and small trials show improved sperm count and motility in men over 3–4 months — though effect sizes are small, trials are small, and female-fertility and energy claims are essentially unsupported. Despite “hormone balancing” marketing, controlled studies show no meaningful change in testosterone, estrogen, FSH, LH, or cortisol. It is generally safe at 1.5–3 g/day (mostly mild GI upset), but its goitrogenic potential warrants caution with thyroid conditions, and it is no substitute for a proper workup of documented infertility.
The Sexual Function Evidence
A 2010 systematic review in BMC Complementary and Alternative Medicine analysed 4 RCTs of maca on sexual dysfunction. Evidence was limited but suggested modest benefit in SSRI-induced sexual dysfunction and in menopausal sexual dysfunction. Effect sizes were small and trials were small. Follow-up trials have been inconsistent.
Fertility Claims
Small trials have shown maca increases sperm count and motility in healthy men over 3–4 months. Effect sizes are modest, studies small, and female fertility evidence essentially absent. For documented infertility, maca is not a substitute for reproductive endocrinology evaluation.
Hormonal Effects
Despite marketing suggesting "hormone balancing," controlled studies generally show maca does not alter serum testosterone, estrogen, FSH, LH, or cortisol meaningfully. Its mechanism likely involves non-hormonal pathways (possibly related to macaenes and macamides, unique alkaloids).
Energy and Performance
Subjective energy claims are popular but poorly supported. Small cycling and endurance trials have shown minimal to no performance improvements. If energy benefit occurs, it is modest and mostly subjective.
Colour Variants and Quality
Maca is sold as yellow, red, and black varieties with different marketing claims (red for female hormone balance, black for male fertility, etc.). Evidence for variety-specific effects is weak. Peruvian-sourced, traditionally processed (gelatinised or cooked) maca is generally considered better tolerated than raw powder. Dose is typically 1.5–3 g/day.
Safety
Maca is generally safe at culinary-to-supplement doses, with main side effects being mild GI upset. Mild goitrogenic potential (like most cruciferous vegetables) — caution with thyroid conditions at high doses. Hormone-sensitive conditions warrant caution despite lack of clear hormonal activity.
Sources
- Shin BC, Lee MS, Yang EJ, Lim HS, Ernst E. "Maca (L. meyenii) for improving sexual function: a systematic review." BMC Complementary and Alternative Medicine, 2010;10:44. PMID 20691074.
- Gonzales GF, Córdova A, Vega K, Chung A, Villena A, Góngora C, Castillo S. "Effect of Lepidium meyenii (MACA) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men." Andrologia, 2002;34(6):367–372.
- Dording CM, Fisher L, Papakostas G, Farabaugh A, Sonawalla S, Fava M, Mischoulon D. "A double-blind, randomized, pilot dose-finding study of maca root (L. meyenii) for the management of SSRI-induced sexual dysfunction." CNS Neuroscience & Therapeutics, 2008;14(3):182–191. PMID 18801111.