About Herbs, Botanicals & Other Products

Scientific Name
Lepidium Meyennii Walp, Lepidium peruvianum Chacon
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Common Name

Maca-maca, maino, ayak chichira, and ayak willku

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Brand Name

Maca Force™

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Clinical Summary

A nutritionally valuable plant native to Peru that grows in a harsh climate above 4,000 feet, maca has been used traditionally to enhance fertility and sexual performance in both men and women and to relieve menopausal symptoms (1). It has been purported to treat cancer and to improve stamina in cancer patients.
Animal studies indicate that maca increases endurance (6) and enhances sexual function (2). The hexanic extract of maca appears to be more effective at improving sexual performance in rats than methanolic and chloroformic extracts (5). Human trials indicate increased libido (3) and improvement in sperm production and sperm motility (4). Maca supplementation may enhance the subjective feeling of sexual well-being (11) and benefit those with sexual dysfunction induced by selective-serotonin reuptake inhibitors (SSRIs) (12). However, the evidence to support use of maca for sexual dysfunction is limited and needs further research (13).

Dried maca was shown to have lower content of the suspected active metabolite than fresh maca. It is also available as a liquor, tonic and mayonnaise, although health benefits of these derivatives seem minimal (7). The therapeutic dose and toxicity of maca are unknown.

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Purported Uses
  • Infertility
  • Menopausal symptoms
  • Sexual performance
  • Strength and stamina
  • Cancer treatment
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Constituents
  • Carbohydrates
  • Amino acids - aspartic acid, glutamic acid, serine, glycine, arginine, valine, phenylalanine, tyrosine, threonine.
  • Fiber
  • Lipids - Fatty Acids, linoleic acid, palmitic acid, oleic acid and sterols
    (1) (7) (6) (8)
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Mechanism of Action

Maca root contains far greater amounts of glucosinolates than other members of the Brassicacae family, such as cabbage, cauliflower and broccoli. Fertility-enhancing properties of maca are thought to be due to aromatic isothiocyanates hydrolyzed from these glucosinolates. Furthermore, benzyl isothiocyanate has been reported to inhibit breast, stomach and liver cancer in rats. Aphrodisiacal properties are attributed to the prostaglandins, sterols and amides of polyunsaturated fatty acids (7). The most confounding question about maca’s effect is its ability to influence sexual performance without affecting serum hormone levels such as luteinizing hormone, follicle stimulating hormone, prolactin, testosterone and estradiol (9). It is therefore assumed that maca acts on the receptors for these hormones (4). Both methanolic and acqueous extracts of Maca exhibit estrogenic activity in vitro (10). Alkaloids purified from the maca root are thought to affect the hypothalamic-pituitary axis, explaining why maca can induce effects in both sexes (6).

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Literature Summary and Critique

Gonzales GF, Cordova A, Vega K, Chung A, Villena A, Gonez C et al. Effect of Lepidium meyenii (MACA) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men. Andrologia 2002;34:367-72.
Fifty-seven male subjects aged 21-56 years participated in a study of the effect of maca in increasing sexual desire. Subjects were randomized into one of three groups. Thirty subjects received 500 mg maca three times a day (1,500 mg/day), another fifteen subjects received 500 mg maca six times a day (3,000 mg/day) and the remainder received placebo for twelve weeks. Subjects were asked to report subjectively about level of sexual desire at 4, 8 and 12 weeks. 40% of men receiving maca reported an increase in sexual desire and eight and twelve weeks. None of the placebo group reported an increase in sexual desire. Results did not appear to be dose-dependent. The study appears to contain a number of statistical flaws which weaken the results. Larger, better run studies are warranted.

Gonzales GF, Cordova A, Gonzales C, Chung A, Vega K, Villena A. Lepidium meyenii (Maca) improved semen parameters in adult men. Asian J Androl 2001;3:301-3.
12 healthy men aged 24-44 participated in a four-month study of the effect of maca on sperm production and motility. Three subjects dropped out for personal reasons. Subjects received either 1,500 or 3,000 mg of maca per day. After four months semen volume, total sperm count, motile sperm count and sperm motility were significantly increased. Serum levels of leuteinizing hormone, follicle stimulating hormone, prolactin, testosterone and estradiol hormones were unaffected. Because the trial was not randomized, observation bias may have been introduced, weakening the results. Further study is warranted.

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References
  1. Muhammad I, Zhao J, Dunbar DC, Khan IA. Constituents of Lepidium meyenii ‘maca’. Phytochemistry 2002;59:105-10.
  2. Zheng BL, He K, Kim CH, Rogers L, Shao Y, Huang ZY et al. Effect of a lipidic extract from lepidium meyenii on sexual behavior in mice and rats. Urology 2000;55:598-602.
  3. Gonzales GF, Cordova A, Vega K, Chung A, Villena A, Gonez Cet al. Effect of Lepidium meyenii (MACA) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men. Andrologia 2002;34:367-72.
  4. Gonzales GF, Cordova A, Gonzales C, Chung A, Vega K, Villena A. Lepidium meyenii (Maca) improved semen parameters in adult men. Asian J Androl 2001;3:301-3.
  5. Cicero AF, Piacente S, Plaza A, Sala E, Arletti R, Pizza C. Hexanic Maca extract improves rat sexual performance more effectively than methanolic and chloroformic Maca extracts. Andrologia 2002;34:177-9.
  6. Balick MJ,.Lee R. Maca: from traditional food crop to energy and libido stimulant. Altern.Ther.Health Med 2002;8:96-8.
  7. Li G, Ammermann U, Quiros CF. Glucosinolate Contents in Maca (Lepidium peruvianum chacon) Seeds, Sprouts, Mature Plants and Several Derived Commercial Products. Economic Botany 2001;55:255-62.
  8. Piacente S, Carbone V, Plaza A, Zampelli A, Pizza C. Investigation of the tuber constituents of maca (Lepidium meyenii Walp.). J Agric.Food Chem. 2002;50:5621-5.
  9. Gonzales GF, Cordova A, Vega K, et al. Effect of Lepidium meyenii (Maca), a root with aphrodisiac and fertility-enhancing properties, on serum reproductive hormone levels in adult healthy men. J Endocrinol 2003;176(1):163-8.
  10. Valentova K, Buckiova D, Kren V, et al. The in vitro biological activity of Lepidium meyenii extracts.Cell Biol Toxicol 2006;22(2):91-9.
  11. Zenico T, Cicero AF, Valmorri L, Mercuriali M, Bercovich E. Subjective effects of Lepidium meyenii (Maca) extract on well-being and sexual performances in patients with mild erectile dysfunction: a randomised, double-blind clinical trial. Andrologia. 2009 Apr;41(2):95-9.
  12. Dording CM, Fisher L, Papakostas G, et al. A double-blind, randomized, pilot dose-finding study of maca root (L. meyenii) for the management of SSRI-induced sexual dysfunction. CNS Neurosci Ther. 2008 Fall;14(3):182-91.
  13. Shin BC, Lee MS, Yang EJ, Lim HS, Ernst E. Maca (L. meyenii) for improving sexual function: a systematic review. BMC Complement Altern Med. 2010 Aug 6;10:44.
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How It Works

Bottom Line: Maca may increase sexual function but it has not been shown effective against cancer.

Maca root is in the same family as cabbage, cauliflower and broccoli. Maca has traditionally been used to improve sexual performance and as a treatment for infertility. Studies have shown that maca is able to improve sexual performance, however it does so without affecting serum hormone levels in the blood. It is possible that maca affects the receptors that these hormones bind to. Because maca affects the body through these hormones, it is assumed that it can produce effects in members of both sexes. Further study is warranted.

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Purported Uses
  • To treat infertility
    No clinical trials support this use.
  • To treat menopausal symptoms
    There is no evidence to back this claim.
  • To improve sexual performance
    A few clinical trials showed increase in sexual desire, sperm count and motility. Further study is warranted.
  • To improve strength and stamina
    This use is not backed by research.
  • To treat cancer
    Scientific evidence is lacking to support this claim.
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Research Evidence

Sexual performance:
Fifty-seven male subjects aged 21-56 years participated in a study of the effect of maca in increasing sexual desire. For twelve weeks subjects received either 500 mg maca three times a day, 500 mg maca six times a day or placebo. Subjects reported subjectively about their sexual desire. Nobody in the placebo group reported increased sexual desire, however 40% of the subjects receiving maca reported increased sexual desire. The study contains a number of statistical flaws which weaken the results.

In another study, twelve healthy men aged 24-44 participated in a four-month study of the effect of maca on sperm production and motility. Subjects received either 1,500 or 3,000 mg of maca per day. Sperm count and mobility increased during the course of the study, however the levels of certain hormones which produce such effects in the body remained unchanged. Because the trial was not randomized, results may be skewed.

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Patient Warnings
  • This product is regulated by the FDA as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. The product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
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Dosage (Inside MSKCC Only)
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Last updated: May 26, 2011