Maca

Background & General Info

Maca, or Lepidium meyenii, is an Andean herbaceous plant of the Brassicaceae family that thrives and is widely cultivated in the Andean region of Peru at an altitude of over 3000 meters (between 4000 and 4500 meters above sea level), ^[1] as well as other South American countries, such as Bolivia and northwest Argentina. ^[2] However, the plant has newly been introduced in Japan, Europe, and the United States but is progressively available commercially in numerous parts of the globe for its therapeutic benefits ^[3], typically as powdered maca or powdered maca extract with alcohol or water or a mixture of both as solvents. ^[4] In fact, maca exportation from Peru has increased from 1,415,000 USD in 2001 to 6,170,000 USD in 2010. ^[5]

The genus name Lepidium comes from the Greek term “lepidion,” which literally translates to “small scale,” the name specified by Dioscorides to refer to the small fruits of this cosmopolitan genus. ^[6] Commonly called as mace, pepper grass, or pepper weed, maca shares the same growth habit, size, and proportions of radishes and turnips but dwells in a very restricted area of cultivation in the puna agroecological zone of central Andes where temperatures can drop below 0°C. ^[7]

Maca - Botany

Maca is a resilient perennial plant that can grow up to 12 to 20 cm even in areas characterized by severe cold, exceptionally intense sunlight, and strong winds. ^[5] In its vegetative state, maca simply looks as a small rosette of leaves that enlarges in the generative phase when it consists of leaves and flowers. ^[6] Maca distinctively has overground and underground parts: the small and flat overground part appears to be the plant’s adaptation to prevent the impact of strong winds, while the underground part comprises the hypocotyl–root axis where high contents of water are stored. ^[5] The conical succulent root can attain a length of about 18 cm and a diameter of about 6.5 cm ^[6], and the radish-like edible parts, that is, the hypocotyls, vary in color in different maca plants, ranging from yellow (47.8% ecotype), to red white (16.5% ecotype), to black (4.2% ecotype), to white (2.2% ecotype), to yellow red (1.3% ecotype). ^[6] The short and decumbent stems of maca hold rosulate, pinnatipartite leaves that are constantly renewed from the rosette’s center. Its racemes are pauciflorous, whereas its fruit measures 4 to 5 mm in size and is dehiscent with two carinated valves, each enclosing an ovoid, reddish-gray 2–2.5-mm seed. ^[7]

Maca - History & Traditional Use

The traditional use of maca to improve fertility in humans and animals dates back to centuries in the Andes during the time of the Spaniard conquest. ^[8] It was domesticated during the pre-Inca archaic period around 3800 BC and since then has been considered as both a nutritive food and a traditional medicine in the Peruvian region for over 2000 years. ^[9] Prehistoric remnants of the first inhabitants of the Peruvian plateau between 4000 and 1200 BC revealed agriculture of maca exploited by the ancient Cusco and Inca civilization as a foodstuff that boosts the strength and physical feat of soldiers and warriors during marches and vicious warfare. ^[6] The first acknowledged account of maca roots was published in 1553, albeit without proper identification of its botanical or common name. Pedro Cieza de León, a conquistador and chronicler of the Spaniard conquest of Peru, witnessed locals of the province of Bombón (Chinchaycocha; presently known as Junin) in the Peruvian highlands employing maca roots for sustenance. ^[5] Father Bernabé Cobo, a prominent Spanish Jesuit missionary, scholar, and writer in Spanish America during the seventeenth century, in his Historia del Nuevo Mundo in 1653, mentioned the fertility-boosting power of maca roots in the Andean region in animals and humans, and because of such purported sexuality-enhancing effect, maca has earned the moniker “Andean ginseng”. ^[2]

In the United States, maca was first introduced in the market as a nonhormonal preparation with probable anti-aging property and has been included as part of the list of estrogenic herbal preparations, along with soy-based products, red clover, wild yam, etc.. ^[10] Medium-sized maca roots (around 5–6 cm long and 3–5 cm wide) are usually preferred by the Indian populations; in contrast, the larger roots, referred to as “shugla,” are excessively rich in fiber and are regarded as of poor nutritional content. ^[6]

Herbal Uses

In the central Andean region of Peru where maca plant flourishes, its subterranean parts are traditionally used principally to improve sexuality and fertility ^[11] and have long been valued as a staple foodstuff, revitalizing vegetable and dietary supplement by indigenous peoples. ^[9] It has also been employed for centuries in the Andes as an adaptogenic to handle anemia, infertility, and female hormone balance ^[3] and as an established remedy for frequent health problems in both men and women, especially female-related conditions such as hormonal imbalances, menstrual irregularities, infertility, and menopausal symptoms, including hot flashes, vaginal dryness, loss of energy and libido, and depression. ^[10]

Natives of the Andean highlands of Peru, Bolivia, and northwest Argentina eat around 50–100 g of naturally dried maca hypocotyls daily as a traditional food. ^[4] The dried maca can be kept away in storage for several years where it occasionally becomes as hard as a rock, and it is boiled in water before being eaten to get hold of a soft product that can be consumed as a juice. ^[5] As a nutritional supplement, the advised dose ranges from 1.5 to 3 g of dried hypocotyls (equivalent to approximately 10 g of fresh maca). ^[4]

Maca - Constituents / Active Components

Quantification through high-performance liquid chromatography analysis of a number of products acquired from processed maca hypocotyls, such as pills, capsules, flour, liquor, tonic, and mayonnaise, identified abundant amounts of aromatic glucosinolates, benzylglucosinolate (glucotropaeolin), and p-methoxybenzylglucosinolate in the fresh and dry hypocotyls and leaves of maca ^[12] Interestingly, the secondary metabolites macaridine, macaene, macamides, and maca alkaloids can only be found in maca. ^[5] Because the two glucosinolates, sinigrin and glucotropaeolin, are unique to maca and do not exist in other plants belong to the family Brassicaceae, both are considered chemotaxonomic markers. 6,7-Benzylated alkamides or macamides are at a concentration of 0.0016–0.0123% in the dried hypocotyls of maca, with total alkamide content ranging from 0.15% to 0.84%. The compound (1R,3S)-1-methyltetrahydro-β-carboline-3-carboxylic acid is also present in maca. ^[4]

Air-dried hypocotyls of maca bear excellent quantities of carbohydrates (about 59%), protein (10%), moisture (10%), and lipids (2%). Analytical composition of maca roots based on data from nutritional studies expressed the following macronutrient percentages ^[13]:

Components:
Water 10.4%
Proteins 10.2%
Lipids 2.2%
Carbohydrates 59%
Whole fiber 8.5%
Ash 4.9%

Maca roots also contain very appreciable amounts of vitamins, amino acids, sterols, and fatty acids and have high concentrations of minerals, especially potassium and iron, aside from tannins and saponins, making them an ideal food due to their wealth of nutrients in appropriate dietary concentrations. ^[4]

Vitamins:
B1 thiamine 0.20 mg
B2 riboflavin 0.35 mg
C 10 mg
E 87 mg

Amino acids: (mg concentration/gram of protein)
Aspartic acid 91.7 mg
Glutamic acid 156.5 mg
Serine 50.4 mg
Histidine 21.9 mg
Glycine 68.3 mg
Threonine 33.1 mg
Alanine 63.1 mg
Arginine 99.4 mg
Tyrosine 30.6 mg
Phenylalanine 55.3 mg
Valine 79.3 mg
Methionine 28.0 mg
Isoleucine 47.4 mg
Leucine 91.0 mg
Lysine 54.3 mg
Proline 0.5 mg
Sarcosine 0.7 mg

Sterols (as steryl acetate derivatives) (Percent of sterol mixture):
Brassicasteryl acetate 9.1%
Ergosterol acetate 13.6%
Campesteryl acetate 27.3%
Ergostadientyl acetate 4.5%
Sitosteryl acetate 45.5%

Fatty acids (as methyl ester derivatives) (Percent of methyl ester mixture):
Dodecanoic (lauric) 0.8%
7-Tridecenoic 0.3%
Tridecanoic 0.1%
Tetradecanoic (myristic) 1.4%
7-Pentadecenoic 0.5%
Pentadecanoic 1.1%
9-Esadecenoic (palmitolete) 2.7%
Hexadecanoic (palmitic) 23.8%
9-Heptadecenoic 1.5%
Heptadecanoic 1.8%
9,12-Octadecadienoic (linoleic) 12.6%
9-Octadecenoic (oleic) 11.1%
Octadecanoic (stearic) 6.7%
11-Nonadecanoic 1.3%
Nonadecanoic 0.4%
15-Eicosenoic 2.3%
Eicosanoic (archidie) 1.6%
Docosanoic (behenic) 2.0%
15-Tetracosenoic (nervonic) 0.4%
Tetracosanoic (lignoceric) 0.4%
Fatty acid saturated 40.1%
Fatty acid unsaturated 52.7%
Saturated/unsaturated ratio 0.76

Minerals (Content in mg/100 g):
Iron 16.6 mg
Manganese 0.8 mg
Copper 5.9 mg
Zinc 3.8 mg
Sodium 18.7 mg
Potassium 2050.0 mg
Calcium 150.0 mg

Maca - Medicinal / Scientific Research

As a traditional folk medicine, maca roots have been claimed to be efficacious in treating or managing a broad array of disorders and medical conditions, and recently, scientific attention has been drawn to the most robustly attested pharmacological actions of maca, such as enhancement of sexual drive in humans, increasing overall vigor and energy levels, and increasing sexual fertility in humans and domestic livestock, to which several scientific studies have provided reliable data as basis. ^[9] Overall, the nutritional, energizing, and fertility-enhancing effects of maca have been scientifically evidenced in various experiments, and recent applications point to its utility against sexual dysfunctions, osteoporosis, and benign prostatic hyperplasia and in improving memory and learning and skin protection against ultraviolet radiation. ^[5] Although maca has long been purported to possess several other medicinal attributes in traditional herbal medicine, still only a few of these attributes have been extensively and thoroughly investigated scientifically and the fact remains that insufficient data elucidate its exact mechanism of action. ^[14]

Sexual Health:

The concern for sexual problems or sexual dysfunctions has become extensive such that, based on data from 18 descriptive epidemiological studies, 20–30% of men and 40–45% of women are afflicted and have reported adverse effects on their mood, well-being, and interpersonal relationships. Preparations from maca root, especially its extract, regularly pop out in Internet searches as among the most commonly mentioned “natural or alternative drugs” for libido improvement and have been clinically evidenced to effectively improve sexual function, although the number of trials still remains limited. In a 2010 systematic review of randomized clinical trials on maca versus placebo treatment in healthy humans with sexual dysfunction, two randomized clinical trials demonstrated the significant favorable effect of maca on sexual dysfunction or sexual desire of healthy menopausal women or adult men, respectively, and another trial, using the International Index of Erectile Dysfunction-5, screened the effectiveness of maca treatment in patients suffering from erectile dysfunction and similarly demonstrated significant effects. Experimental studies in animals pointed out the spermatogenic and fertility-enhancing activities of maca, which are attributable to its phytosterol or phytoestrogen contents, and a number of in vivo studies using rat models have revealed the ability of maca to enhance sexual behavior and androgen-like effects. ^[8]

The study results of Gonzales et al. (2001) showed that oral administration of an aqueous extract from maca roots at a dose of 66.7 mg/mL invigorates the initial stages of spermatogenesis in male Holtzman rats by acting on their initial stages (IX–XIV). Provided two times a day for 14 consecutive days, the treatment with maca root extract increased the weights of testis and epididymis of rats, although the weight of the seminal vesicle remained unaffected. There were also an observed increase in the length and frequency of stage IX–XIV seminiferous tubules, where mitosis happened, and a decrease in stages I–VI. ^[2] These findings on spermatogenesis are congruous with those of Gonzales C. et al. (2006), who similarly evaluated the differential effects of short-term (7 days) and long-term (42 days) treatments with three ecotypes of maca, namely, red, yellow, and black macas, on spermatogenesis in rats. Maca treatment for 7 days resulted in a significant increase in the length of stage VIII (p < 0.05) in the case of yellow and red macas and in stages II–VI and VIII (p < 0.05) for the black maca. An increase in daily sperm production, compared with control values (p < 0.05), was observed only in the group treated with black maca. As regards long-term maca treatment, among the three ecotypes, it was found that only the black maca improved the daily sperm production (p < 0.05) and increased the epididymal sperm motility (p < 0.05). In relation to the control group, the red maca treatment did not influence testicular and epididymal weight and epididymal sperm motility and sperm count, but did significantly decrease the prostate weight (p < 0.05). ^[1]

In the study of Zheng et al. (2000), orally administered purified lipidic extracts from maca, namely, MacaPure M-01 and M-02, have been demonstrated to improve sexual function of examined mice and rats and to display aphrodisiac activity. Mice and rats belonging to the experimental group received 10% ethanol suspension of M-01 and M-02 for 22 days, and after such time, two virgin female mice were introduced to a male mouse. The number of complete intromissions of each male mouse in 3 hours was documented, with one male sharing a place with five estrous female mice overnight in an assessment of 1-day mating. The results indicated an increase in the number of complete intromissions in normal male mice during the 3-hour period, with 16.33 ± 1.78, 46.67 ± 2.39, and 67.01 ± 2.55 for the control, M-01, and M-02 groups, respectively. There was also an increase in the number of sperm-positive females in normal mice during the assessment of mating, with 0.6 ± 0.7 for the control group and 1.5 ± 0.5 in the M-01 experimental group. The latent period of erection, which was measured to assess the sexual function of male rats with erectile dysfunction, was 112 ± 13 seconds in the control group with a regular diet, but this period decreased to 54 ± 12 seconds, 54 ± 13 seconds, 71 ± 12 seconds, 73 ± 12 seconds, and 41 ± 13 seconds upon oral administration of 180 mg/kg of M-01, 1800 mg/kg of M-01, 45 mg/kg of M-02, 180 mg/kg of M-02, and 1800 mg/kg of M-02, respectively. ^[15]

A 2001 study involving nine 24–44-year-old healthy men concluded that maca treatment improved sperm production and sperm motility through mechanisms not related to serum luteinizing hormone, follicle-stimulating hormone, prolactin, testosterone, and estradiol. The treatment consisted of 4 months of oral treatment with maca tablets at a dose of 1500 or 3000 mg/day. The study results showed significantly increased seminal volume, total sperm count, motile sperm count, and sperm motility (p < 0.05) as a result of maca treatment, with the serum hormone levels remaining unchanged and the increase in sperm count being not related to dose of maca. ^[11] A 2002 double-blind, placebo-controlled, randomized, parallel trial that lasted for 12 weeks revealed the efficacy of active maca treatment given at different doses in improving sexual desire. This trial enrolled men aged 21–56 years to maca treatment at a dose of 1,500 mg or 3,000 mg and to placebo in order to determine if the effect of maca on subjective report of sexual desire was related to mood or serum testosterone levels. Starting at the eight week of treatment, maca treatment had been observed to enhance sexual treatment, although there was no statistical difference between the serum testosterone and estradiol levels of treated men and those belonging to the placebo group. Based on logistic regression analysis, the independent effect of maca on sexual desire at 8 and 12 weeks of treatment was not linked to changes either in Hamilton scores for depression or anxiety or in serum testosterone and estradiol levels. ^[16]

Endurance Enhancer:

Not only is maca a popular natural enhancer of sexual drive, but also it has been consumed of late as a sports supplement to improve strength and endurance in athletes. A pilot investigation conducted by Stone et al. (2009) explored the effect of maca supplementation on physical activity and sexual desire in sportsmen. This randomized crossover study engaged eight participants to each finish a 40-km cycling time trial before and after 14 days of both maca extract and placebo supplementation and to complete a sexual desire inventory during each visit. Compared with baseline, a markedly improved 40-km cycling time performance was observed upon maca extract administration (p = 0.01); however, this is not the case when compared with the placebo trial after supplementation (p > 0.05). The administration of maca extract had also significantly boosted the self-rated sexual desire score of the study participants when compared with the baseline test (p = 0.01) and placebo trial after supplementation (p = 0.03). ^[17]

Learning And Memory:

In the experimental study of Rubio et al. (2006), black maca displayed more advantageous effects in terms of latent learning in treated ovariectomized mice than yellow and red macas, as evaluated using the water-finding task wherein trained mice treated with black maca exhibited the best response. The three varieties however were found to be significantly effective in decreasing finding latency in nontrained and trained mice (p < 0.05). Based on the forced swimming test, the three different cultivars manifested antidepressant activity, decreased the immobility time, and increased the uterine weight of ovariectomized mice. ^[18]

Menopause:

In postmenopausal women, some studies pointed out the potential of maca as an attractive nonhormonal alternative to hormone replacement therapy, which still serves as the mainstay treatment of menopausal symptoms despite its increased risk of breast cancer and coronary heart disease occurrence over its long-term use. A 2011 systematic review concerning the effectiveness of maca as a treatment for menopausal symptoms accumulated four randomized clinical trials revealing positive effects of maca against menopausal symptoms using the Kupperman Menopausal Index and the Greene Climacteric Score. By means of the Cochrane “risk of bias” assessment tool, these clinical trials were screened for methodological quality and all trials investigated the effects of any type of maca preparation on menopausal symptoms in healthy perimenopausal, early postmenopausal, and late postmenopausal women. ^[3] One of these randomized clinical trials is that of Meissner et al. (2006), which enrolled 168 Caucasian early-postmenopausal women aged >49 years to treatment of either placebo or pregelatinized organic maca (Maca-GO). Under a double-blind, randomized, placebo-corrected design, this clinical study was conducted in five outpatient sites and involved study participants with a follicle-stimulating hormone level of >30 IU/mL and an estrogen level of <40 pg/mL at admission who were instructed to self-administer either two 500 mg of vegetable hard gel capsules with Maca-GO (a total of 2 g/day) or placebo powder two times a day with meals for three or four months. In the 124 women who finished the study, the production of E2 was significantly induced by Maca-GO (p < 0.001), which was accompanied by a simultaneous inhibition of follicle-stimulating hormone in the blood (p < 0.05) and a significant elevation of high-density lipoproteins (p < 0.05). There was also a reduction of both frequency and severity of individual menopausal symptoms, particularly hot flushes and night sweating, due to Maca-GO treatment, leading to a significant decrease in Kupperman Index score from 22 to 10 (p <= 0.001). ^[10] As suggested by the early laboratory study results of Chacon (1961), the plant sterols present in maca appear to act as biochemical triggers that aid the human body to boost or decrease the production of individual hormones and to regulate their levels accordingly with respect to age and gender. ^[19]

Cytoprotective:

Valentová et al. (2006) noted a cytoprotective effect likely not mediated by antioxidant capacity in methanol and aqueous extracts obtained from dehydrated maca hypocotyls. Both extracts suppressed the leakage of lactate dehydrogenase and aspartate aminotransferase from rat hepatocytes after 72 hours of treatment, but exhibited weak antioxidant activity according to the DPPH radical scavenging test, with IC50 values of 3.46 ± 0.16 mg/mL and 0.71 ± 0.10 mg/mL for aqueous and methanol extracts, respectively. This suggests that the observed inhibition of spontaneous leakage of enzymes is possibly mediated by mechanisms other than antioxidant activity. Additionally, the methanol and aqueous extracts displayed estrogenic activity analogous to that of silymarin in MCF-7 cell line, which is in the range of 100–200 μg of extract/mL. ^[20]

Neuroprotective:

Pino-Figueroa, Nguyen, and Maher (2010) illustrated the neuroprotective activity of maca in both in vitro and in vivo experimental models. Upon microscopic and chemical determination of viability, a significant relationship between concentration and neuroprotective effect was found in crayfish neurons pretreated with vehicle or maca pentane extract and then subjected to H2O2. In rat models, the pentane extract was administered intravenously before and after middle cerebral artery occlusion, and the results indicated decreased infarct volumes for the lower dose but increased infarct volumes for higher doses when compared with controls. ^[21]

Maca - Contraindications, Interactions, And Safety

The toxicity of maca is apparently low, with an LD50 of less than 16.3 g/kg in mice, and no toxicity has been observed so far in both in vivo and in vitro studies where maca was administered after being boiled. ^[3] A careful scan of scientific literature consisting of numerous studies would point toward the low degree of acute oral toxicity of maca treatment in animals and low cellular toxicity in vitro. ^[14] Furthermore, a 2009 PubMed search using the terms “Lepidium meyenii,” “maca,” and “adverse” or “safe” or “safety” came up with no case reports concerning adverse reactions associated with maca-based products, whereas an FDA MedWatch search disclosed 22 reports that dated January 2001 to July 2009 and that examined multi-ingredient products containing maca as one of the components. These reports took note of 18 nonserious reactions (numbness, headache, transient global amnesia, dermatological reactions, seizure, priapism, gastritis, sleep deprivation, bleeding, dizziness, and heart palpitations) and four serious reactions. Diarrhea, palpitations, sweating, shaking, nausea, abdominal pain, malaise, dizziness, and tachycardia were reported as adverse effects for maca and maca products according to the ten reports from the Canada Vigilance Program database. ^[4]

Maca appears to interact with selective serotonin reuptake inhibitors (SSRIs) such as escitalopram, citalopram, fluoxetine, or paroxetine, which are antidepressant drugs, and patients under anticoagulant medications such as warfarin should best avoid the consumption of maca because of its high concentration of vitamin K, which, along with an anticoagulant, can adversely affect bleeding parameters. Because of limited research regarding its safety, the Natural Medicines Comprehensive Database advises the avoidance of maca use during pregnancy and breastfeeding. ^[4]

References:

[1] C. Gonzales, J. Rubio, M. Gasco, J. Nieto, S. Yucra and G. Gonzales, "Effect of short-term and long-term treatments with three ecotypes of Lepidium meyenii (MACA) on spermatogenesis in rats," Journal of Ethnopharmacology, vol. 103, no. 3, p. 448–454, 2006. https://www.ncbi.nlm.nih.gov/pubmed/16174556

[2] G. Gonzales, A. Ruiz, C. Gonzales, L. Villegas and A. Cordova, "Effect of Lepidium meyenii (maca) roots on spermatogenesis of male rats," Asian Journal of Andrology, vol. 3, no. 3, p. 231–233, 2001. https://www.ncbi.nlm.nih.gov/pubmed/11561196

[3] M. Lee, B.-C. Shin, E. Yang, H.-J. Lim and E. Ernst, "Maca ( Lepidium meyenii ) for treatment of menopausal symptoms: A systematic review," Maturitas, vol. 70, no. 3, p. 227–233, 2011. https://www.ncbi.nlm.nih.gov/pubmed/21840656

[4] "USP Safety Review of Maca," USP Dietary Supplements Compendium. https://www.usp.org/sites/default/files/usp_pdf/EN/dietarySupp/dsc2012samplesafety_review.pdf

[5] G. F. Gonzales, "Ethnobiology and ethnopharmacology of Lepidium meyenii (maca), a plant from the Peruvian highlands," Evidence-Based Complementary and Alternative Medicine, vol. 2012, p. 193496, 2012. https://www.ncbi.nlm.nih.gov/pubmed/21977053

[6] A. Bianchi, "Maca Lepidium meyenii," Boletín Latinoamericano y del Caribe de Plantas Medicinales y Aromáticas, vol. 2, no. 3, p. 30–36, 2003. https://www.redalyc.org/pdf/856/85620303.pdf

[7] Food and Agriculture Organization of the United Nations, "Neglected crops: 1492 from a different perspective—Andean roots," Agriculture and Consumer Protection. https://www.fao.org/docrep/t0646e/t0646e0h.htm

[8] B.-C. Shin, M. Lee, E. Yang, H.-S. Lim and E. Ernst, "Maca (L. meyenii) for improving sexual function: a systematic review," BMC Complementary and Alternative Medicine, vol. 10, p. 44, 2010. https://www.ncbi.nlm.nih.gov/pubmed/20691074

[9] Y. Wang, Y. Wang, B. McNeil and L. Harvey, "Maca: An Andean crop with multi-pharmacological functions," Food Research International, vol. 40, no. 7, p. 783–792, 2007. https://www.researchgate.net/publication/248425831_Maca_An_Andean_crop_with_multi-pharmacological_functions

[10] H. Meissner, A. Mscisz, H. Reich-Bilinska and W. Kapczynski, "Hormone-balancing effect of pre-gelatinized organic maca (Lepidium peruvianum Chacon): (II) Physiological and symptomatic responses of early-postmenopausal women to standardized doses of maca in double blind, randomized, placebo-controlled, multi-centre clinical study," International Journal of Biomedical Science, vol. 2, no. 4, p. 360–374, 2006. https://www.ncbi.nlm.nih.gov/pubmed/23675005

[11] G. Gonzales, A. Cordova, C. Gonzales, A. Chung, K. Vega and A. Villena, "Lepidium meyenii (Maca) improved semen parameters in adult men," Asian Journal of Andrology, vol. 3, no. 4, p. 301–303, 2001. https://www.ncbi.nlm.nih.gov/pubmed/11753476

[12] G. Li, U. Ammermann and C. Quirós, "Glucosinolate contents in maca (Lepidium peruvianum Chacón) seeds, sprouts, mature plants and several derived commercial products," Economic Botany, vol. 55, no. 2, p. 255–262, 2001. https://www.researchgate.net/publication/225108951

[13] "Maca Root Composition Profile," The National University of Agriculture, 2013. https://www.macaperu.com/maca_composition.htm

[14] L. J. Valerio and G. Gonzales, "Toxicological aspects of the South American herbs cat's claw (Uncaria tomentosa) and Maca (Lepidium meyenii) : a critical synopsis," Toxicological Reviews, vol. 24, no. 1, p. 11–35, 2005. https://www.ncbi.nlm.nih.gov/pubmed/16042502

[15] B. Zheng, K. He, C. Kim and e. al., "Effect of a lipidic extract from Lepidium meyenii on sexual behavior in mice and rats," Urology, vol. 55, no. 4, p. 598–602, 2000. https://www.ncbi.nlm.nih.gov/pubmed/10736519

[16] G. Gonzales, A. Córdova, K. Vega, A. Chung, A. Villena, C. Góñez and S. Castillo, "Effect of Lepidium meyenii (MACA) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men," Andrologia, vol. 34, no. 6, p. 367–372, 2002. https://www.ncbi.nlm.nih.gov/pubmed/12472620

[17] M. Stone, A. Ibarra, M. Roller, A. Zangara and E. Stevenson, "A pilot investigation into the effect of maca supplementation on physical activity and sexual desire in sportsmen," Journal of Ethnopharmacology, vol. 126, no. 3, p. 574–576, 2009. https://www.ncbi.nlm.nih.gov/pubmed/19781622

[18] J. Rubio, M. Caldas, S. Dávila, M. Gasco and G. Gonzales, "Effect of three different cultivars of Lepidium meyenii (Maca) on learning and depression in ovariectomized mice," BMC Complementary and Alternative Medicine, vol. 6, p. 23, 2006. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1534053/

[19] R. Chacon, "Phytochemical study on Lepidium meyenii," Universidad Nacional Mayor de San Marcos, Lima, Peru, 1961. https://science.report/pub/29192412

[20] K. Valentová, D. Buckiová, V. Kren, J. Peknicová, J. Ulrichová and V. Simánek, "The in vitro biological activity of Lepidium meyenii extracts," Cell Biology and Toxicology, vol. 22, no. 2, p. 91–99, 2006. https://www.ncbi.nlm.nih.gov/pubmed/16528448

[21] A. Pino-Figueroa, D. Nguyen and T. Maher, "Neuroprotective effects of Lepidium meyenii (Maca)," Annals of the New York Academy of Sciences, vol. 1199, p. 77–85, 2010. https://www.ncbi.nlm.nih.gov/pubmed/20633111

1. Famous Chef Sheds 60lbs Researching New Paleo Recipes: Get The Cookbook FREE Here

2. #1 muscle that eliminates joint and back pain, anxiety and looking fat

3. Drink THIS first thing in the morning (3 major benefits)

4. [PROOF] Reverse Diabetes with a "Pancreas Jumpstart"

5. Why Some People LOOK Fat that Aren't

6. Amazing Secret Techniques To Protect Your Home From Thieves, Looters And Thugs

7. The #1 WORST food that CAUSES Faster Aging (beware -- Are you eating this?)

If you enjoyed this page: