Maca is a Peruvian root vegetable used both as food and medicine. It is sometimes called "Peruvian ginseng," not because the plants have any botanical relationship, but because their traditional uses are somewhat similar. Traditionally, maca has been said to increase energy and stamina, and enhance both fertility and sex drive in men and women.
Maca is widely marketed for improving male sexual function, female sexual function, and both male fertility and female fertility. However, at present there is no reliable evidence that it actually provides any benefits at all.
Much of the evidence for maca comes from animal studies. In one study in rats, use of maca enhanced male sexual function.1 Animal studies have had mixed results regarding male and female fertility.2-7
There are two published human trials on maca, performed by a single research group.
In one small 12-week, double-blind, placebo-controlled study, use of maca at 1,500 mg or 3,000 mg increased male libido.8 While this was an interesting finding, the study did not report benefits in male sexual function, just desire. Since loss of sexual function (eg, impotence) is a more common problem in men than loss of sexual desire, these results do not justify the widespread claim that maca has been shown to act like a kind of herbal Viagra.
Another small study found that 4 months of maca use increased sperm count and sperm function.9 Unfortunately, this study failed to use a control group, and for this reason its results are essentially meaningless. (For more information on why studies must use a control group, see Why Does This Database Rely on Double-blind Studies?)
There are no human trials on maca for female fertility or female sexual function.
Contrary to widespread reporting, maca does not appear to increase testosterone levels, or, in fact, affect any male hormones.10
Other animal studies hint that maca might offer benefits for prostate enlargement,11,12 stress,13 diabetes,14 and high blood pressure.15 However, this evidence is as yet too weak to justify any claims regarding maca and these conditions.
The usual dose of maca is 500 to 1,000 mg three times a day.
In the two reported human clinical trials, use of maca has not led to any serious adverse effects. However, this herb has not undergone comprehensive safety testing. Safety in young children, pregnant or nursing women, or people with severe liver or kidney disease has not been established.
1. Cicero AF, Piacente S, Plaza A, et al. Hexanic Maca extract improves rat sexual performance more effectively than methanolic and chloroformic Maca extracts. Andrologia. 2002;34:177-179.
2. Ruiz-Luna AC, Salazar S, Aspajo NJ, et al. Lepidium meyenii (Maca) increases litter size in normal adult female mice. Reprod Biol Endocrinol. 2005;3:16.
3. Oshima M, Gu Y, Tsukada S, et al. Effects of Lepidium meyenii Walp and Jatropha macrantha on blood levels of estradiol-17 beta, progesterone, testosterone and the rate of embryo implantation in mice. J Vet Med Sci. 2003;65:1145-1146.
4. Chung F, Rubio J, Gonzales C, et al. Dose-response effects of Lepidium meyenii (Maca) aqueous extract on testicular function and weight of different organs in adult rats. J Ethnopharmacol. 2005;98:143-147.
5. Gonzales GF, Rubio J, Chung A, et al. Effect of alcoholic extract of Lepidium meyenii (Maca) on testicular function in male rats. Asian J Androl. 2003;5:349-352.
6. Bustos-Obregon E, Yucra S, Gonzales GF, et al. Lepidium meyenii (Maca) reduces spermatogenic damage induced by a single dose of malathion in mice. Asian J Androl. 2005;7:71-76.
7. Gonzales GF, Gasco M, Cordova A, et al. Effect of Lepidium meyenii (Maca) on spermatogenesis in male rats acutely exposed to high altitude (4340 m). J Endocrinol. 2004;180:87-95.
8. Gonzales GF, Cordova A, Vega K, 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.
9. Gonzales GF, Cordova A, Gonzales C, et al. Lepidium meyenii (Maca) improved semen parameters in adult men. Asian J Androl. 2002;3:301-303.
10. 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;176:163-168.
11. Gonzales GF, Miranda S, Nieto J, et al. Red maca ( Lepidium meyenii) reduced prostate size in rats. ReprodBiol Endocrinol. 2005;3:5.
12. Martinez Caballero S, Carricajo Fernandez C, Perez-Fernandez R, et al. Effect of an integral suspension of Lepidium latifolium on prostate hyperplasia in rats. Fitoterapia. 2004;75:187-191.
13. Lopez-Fando A, Gomez-Serranillos MP, Iglesias I, et al. Lepidium peruvianum chacon restores homeostasis impaired by restraint stress. Phytother Res. 2004;18:471-474.
14. Eddouks M, Maghrani M, Zeggwagh NA, et al. Study of the hypoglycaemic activity of Lepidium sativum L. aqueous extract in normal and diabetic rats. J Ethnopharmacol. 2005;97:391-395.
15. Maghrani M, Zeggwagh NA, Michel JB, et al. Antihypertensive effect of Lepidium sativum L. in spontaneously hypertensive rats. J Ethnopharmacol. 2005 Jun 11. [Epub ahead of print]
16. Mehta K, Gala J, Bhasale S, et al. Comparison of glucosamine sulfate and a polyherbal supplement for the relief of osteoarthritis of the knee: a randomized controlled trial [ISRCTN25438351]. BMC Complement Altern Med. 2007 Oct 31. [Epub ahead of print]
Last reviewed August 2013 by EBSCO CAM Review Board
Last Updated: 8/22/2013