Parts Used & Where Grown
Maca is a cruciferous vegetable in the mustard family, related to radishes and turnips. Used as food and medicine in the Andes Mountains of Peru, it is not known to occur naturally anywhere else in the world. The four major cultivars of maca are red, black, cream, and purple; none has been definitely proven to be medicinally superior to any other.
Our proprietary "Star-Rating" system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2 Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
This supplement has been used in connection with the following health conditions:
1,500 to 3,000 mg daily
A small clinical trial found that healthy men who took dried maca powder had increased sperm counts and enhanced sperm motility.4
2.5 to 3 grams per day for 6 to 12 weeks
Maca (Lepidium meyenii) has been used traditionally for balancing female hormones. A review of randomized controlled trials concluded that maca appeared to be beneficial in the treatment of menopausal symptoms. The amount used in these studies was 2.5 to 3 grams per day for 6 to 12 weeks.5
Refer to label instructions
The herbs discussed here are considered members of a controversial category known as adaptogens, which are thought to increase the body's resistance to stress, and to generally enhance physical and mental functioning.6 , 7 Many animal studies have shown that various herbal adaptogens have protective effects against physically stressful experiences,8 , 9 but whether these findings are relevant to human stress experiences is debatable.
Animal studies have shown that maca can reduce the negative effects of stress; however, whether maca is effective in humans is unknown.10
Traditional Use (May Not Be Supported by Scientific Studies)
Maca root has been an important food for the native people in the Andes of Peru, including the Incas, for at least 2,000 years.1 It is eaten baked, dried, mixed with milk, or in a variety of other forms and dishes. It is also traditionally believed to enhance strength, endurance, libido, and fertility.2
How It Works
How It Works
Maca contains substantial quantities of protein, fat, fiber , and minerals including iron , which also contribute to its nutritional value. It also contains glucosinolates,11 the strong-smelling compounds that are responsible for the pungent smell and taste of mustard family plants. Neither these nor any other constituents in maca have definitively been shown to contribute to its actions.
Preliminary studies have shown that maca can increase libido in healthy men.12 It does this without influencing levels of testosterone or any other sex hormones.13 Healthy men who take maca have also been shown to have increased semen volume, increased sperm counts, and enhanced sperm motility.14
Numerous animal studies show that maca extracts can increase sex drive and improve fertility.15 , 16 , 17 Other studies support that it can relieve the negative effects of stress reactions.18 The red cultivar, though not the black or cream, also reduced enlarged prostates in rats.19
How to Use It
The amount used successfully in studies so far has been 500 to 1,000 mg three times per day of dried root powder in capsules.20
Interactions with Supplements, Foods, & Other Compounds
Interactions with Medicines
Glucosinolates can cause goiter (swollen thyroid gland with decreased activity) if taken in excess combined with a low-iodine diet. Though this is documented to occur with other glucosinolate-rich foods, it is not known if maca causes goiter.
1. Valentova K, Ulrichova J. Smallanthus sonchifolius and Lepidium meyenii - prospective Andean crops for the prevention of chronic diseases. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2003;147:119-30.
2. Smith E. Maca root: Modern rediscovery of an ancient Andean fertility food. J Amer Herbalists Guild 2003;4:15-21.
3. 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;34:367-72.
4. Gonzales GF, Cordova A, Gonzales C, et al. Lepidium meyenii (maca) improved semen parameters in adult men. Asian J Androl 2001;3:301-3.
5. Lee MS, Shin BC, Yang EJ, et al. Maca (Lepidium meyenii) for treatment of menopausal symptoms: A systematic review. Maturitas 2011;70:227-33.
6. Brekhman II, Dardymov IV. New substances of plant origin which increase nonspecific resistance. Annu Rev Pharmacol 1969;9:419-30 [review].
7. Panossian A, Wikman G, Wagner H. Plant adaptogens. III. Earlier and more recent aspects and concepts on their mode of action. Phytomedicine 1999;6:287-300 [review].
8. Rege NN, Thatte UM, Dahanukar SA. Adaptogenic properties of six rasayana herbs used in Ayurvedic medicine. Phytother Res 1999;13:275-91 [review].
9. Wagner H, Nrr H, Winterhoff H. Plant adaptogens. Phytomed 1994;1:6376 [review].
10. Lopez-Fando A, Gomez-Serranillos MP, Iglesias I, et al. Lepidium peruvianum Chacon restores homeostasis impaired by restraint stress. Phytother Res 2004;18:471-4.
11. 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.
12. 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. Andrologia2002;34:367-72.
13. 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;176:163-8.
14. Gonzales GF, Cordova A, Gonzales C, et al. Lepidium meyenii (maca) improved semen parameters in adult men. Asian J Androl 2001;3:301-3.
15. Cicero AF, Piacente S, Plaza A, et al. Hexanic maca extract improves rat sexual performance more effectively than methanolic and chloroformic maca extracts. Andrologia2002;34:177-9.
16. Gonzales GF, Ruiz A, Gonzales C, et al. Effect of Lepidium meyenii (maca) roots on spermatogenesis of male rats. Asian J Androl 2001;3:231-3.
17. Ruiz-Luna AC, Salazar S, Aspajo NJ, et al. Lepidium meyenii (maca) increases litter size in normal adult female mice. Reprod Biol Endocrinol2005;3:16.
18. Lopez-Fando A, Gomez-Serranillos MP, Iglesias I, et al. Lepidium peruvianum Chacon restores homeostasis impaired by restraint stress. Phytother Res 2004;18:471-4.
19. Gonzales GF, Miranda S, Nieto J, et al. Red maca (Lepidium meyenii) reduced prostate size in rats. Reprod Biol Endocrinol 2005;3:5.
20. Gonzales GF, Cordova A, Gonzales C, et al. Lepidium meyenii (maca) improved semen parameters in adult men. Asian J Androl 2001;3:301-3.
Last Review: 09-04-2013
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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2014.
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