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Unspecified Color

Despite the compelling evidence that the colors of maca vary in their composition and impact on various health conditions, much of the published literature does not disclose the color(s) studied, creating a challenge in understanding the potential health benefits and highlighting the need for color-specific studies to be completed. A 2022 systematic review and meta-analysis revealed that 50% of the articles published did not state the color(s) used.


The research suggests that maca, without specifying the color(s), support:

  • Mood regulation (anxiety and depression)

  • Sexual health (libido, erectile dysfunction

  • Reproductive health (sperm health

  • Cardiometabolic health (blood pressure, cholesterol, triglycerides, glucose)

  • Lowering inflammation

  • Energy

  • Menopausal symptoms (hot flashes, insomnia)

Below is a compilation of the available literature (including animals and humans) for unspecified colors of maca, with an overview and a summary of the findings provided. 

April 2022

The improvements of daily fatigue in women following the intake of maca (Lepidium meyenii) extract containing benzyl glucosinolate

Human study, N=60 Japanese women 20-65 yo

doi: 10.31989/ffhd.v12i4.912

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Summary of Findings:

  • Unspecified color of maca was taken at a dose of 200 mg twice daily by women reporting fatigue

  • Significant decrease in fatigue (p<0.001), as measured by visual analogue scale (VAS) in women 20-45 yo

November 2020

Does Lepidium meyenii (Maca) improve seminal quality?

Human study, N=69, men ages 20-40

PMID: 32654242

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Summary of Findings:

  • Unspecified color of maca was taken in a dose of 1,000 mg twice daily

  • Significant increase in sperm concentration (p<0.011) by 31.69%

  • Though not of statistical significance, sperm motility increased by 10.48% and morphology of spermatozoa increased by 6.33%.

March 2019

Clinical Effect of Oral Adminstrastion of Maca (Lepidium meyenii) Extract on Japenese Peri-Menopsual Women Subjects: A Randomized, Double-Blind, Placebo-Controlled Study

Human study, N=42, Japanese women, ages 40-59

Not indexed on PubMed

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Summary of Findings:

  • Unspecified color of maca known as Maca-BG1.2, was taken in a dose of 300 mg per day

  • E2 level showed a 2.2-fold increase though not of significance; further analysis revealed serum E2 level in the peri-menopausal subjects with regular menstruation cycle displayed a mostly significant change

  • Marginal decrease in insomnia and hot flushes. 

  • Women with mild symptoms achieved the greatest improvements in reducing menopausal symptoms. 

December 2018

Lepidium meyenii Walp Exhibits Anti-Inflammatory Activity against ConA-Induced Acute Hepatitis

Animal study, female mice

PMID: 30647537

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Summary of Findings:

Maca extract 

  • Significantly suppressed multiple inflammatory cytokines

  • Moderated liver injury in ConA-induced acute hepatitis

  • Suppressed infiltration of natural killer T cells and macrophages

  • "In this study, we found that the protective effects of Maca extract ameliorate ConA-induced acute hepatitis (CIH) and underlying mechanisms."

August 2016

Preservation of Cognitive Function by Lepidium meyenii (Maca) Is Associated with Improvement of Mitochondrial Activity and Upregulation of Autophagy-Related Proteins in Middle-Aged Mouse Cortex

Animal study, middle-aged mice

PMID: 27648102

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Summary of Findings:

  • Maca treated mice had improvements in memory retention.

  • Improved motor coordination was observed in mice that were administered maca. 

  • A significant increase in swim time to exhaustion, suggesting maca's antifatigue property.

  • A significant increase in oxidative phosphorylation enzyme complexes, suggesting an improvement in mitochondrial function. 

  • A significant upregulation of the expression of autophagy-related proteins.

  • "In summary, the present study demonstrated for the first time that maca improves cognitive function in middle-aged mice, and this effect may be associated with improved mitochondrial respiratory function and upregulation of autophagy-related proteins."

February 2015

Maca reduces blood pressure and depression, in a pilot study in postmenopausal women

Human study, N=34, postmenopausal women, ages 46-59

PMID: 24931003

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Summary of Findings:

Unspecified color of maca was taken for 6 weeks at a dose of 3.3 grams per day, with a 6-week crossover of placebo.

After 6 weeks of treatment, the maca group showed significant changes in:

  • Decrease in systolic (p=0.05) and diastolic (p=0.01) blood pressure

  • 10.8% increase general well-being (p<0.05)

  • 13.5% increase mental health (p<0.05)

  • 16.4% increase social functioning (p<0.05)

  • 13% increase mental component score (p<0.05)

  • Significant reduction of menopausal symptoms measured by GCS by 30% (p=0.04) including reduction in anxiety (p=0.02, depression (p<0.01) and somatic (p<0.03);

  • No differences in E2, FSH, LH, SHBG, glucose, lipid profile, serum cytokines or vasomotor symptoms

July-August 2014

Effect of ethanolic extract of Lepidium meyenii Walp on serum hormone levels in ovariectomized rats

Animal study, ovariectomized rats

PMID: 25097281

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Summary of Findings:

  • An ethanolic extract of maca was given to ovariectomized rats for 28 weeks in two doses, 0.096g/kg body weight (low dose) and 0.24 g/kg body weight (high dose).

  • At 28 weeks, a significant increase in estradiol and a significant decrease in FSH was observed using the lose dose of maca. 

  • The higher dose of maca did not affect estradiol levels. 

February 2014

Lepidium meyenii (Maca) enhances the serum levels of luteinising hormone in female rats

Animal study, female rats

PMID: 24333960

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Summary of Findings:

  • Female rats were fed 5%, 25% or 50% diet of maca.

  • A significant increase in luteinizing hormone and follicle stimulating hormone levels (p<0.01). 

  • "The present study demonstrates that Maca uniquely enhances the LH serum levels of pituitary hormones in female rats during the pro-oestrus LH surge and acts in a pharmacological, dose-dependent manner. These findings support the traditional use of Maca to enhance fertility and suggest a potential molecular mechanism responsible for its effects."

December 2013

Role of maca (Lepidium meyenii) consumption on serum interleukin-6 levels and health status in populations living in the Peruvian Central Andes over 4000 m of altitude

Human study, N=50, men and women

PMID: 23934543

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Summary of Findings:

Population based study, comparing individuals who consumed maca, as a food source, to those who did not.

Compared to non-consumer, the regular consumers of maca had: 

  • Higher serum Estradiol (E2) (p<0.01) and health scores (p<0.01)

  • Lower systolic blood pressure (p<0.05), serum T levels (p<0.05),T/E2 ratio (p<0.05), serum IL-6 levels (p<0.05), and CMS scores  (p<0.01)

  • Performed better on the lower limb strength test (p<0.01)

  • The lowest IL-6 levels were observed when maca was consumed in greater quantities (15.9+/- 3.08 grams per day) and for the longer durations (17.8 +/-4.48 years for 41.9+/- 4.48 days per year)

October 2013

A placebo-controlled double-blind randomized trial of the effect of oral supplementation with spermotrend, maca extract (Lepidium meyenii) or l-carnitine in semen parameters of infertile men

Human study, N=60 infertile men

Not indexed on PubMed

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Summary of Findings:

  • An unspecified color of maca was taken in a dose of 1 gram twice daily for 90 days. 

  • Maca improved sperm motility (p<0.05)

March 2011

First case report of testosterone assay-interference in a female taking maca (Lepidium meyenii)

Human Case Report, N=1

PMID: 22700073

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Summary of Findings:

  • Unspecified maca extract was consumed, 1 tsp. powder daily

  • Maca consumption increased plasma testosterone levels without features of virilization. 

  • Maca may cause testosterone immunoassay interference in females. (Testosterone immunoassays use direct immunoassays which are prone to interference from androgenic compounds resulting in falsely elevated testosterone levels.)

December 2010

Effect of the Lepidium meyenii (Maca) on the spermatogenesis and the spermatic quality of subjects with diagnosis of infertility: study of cases.

Human study, N=10 infertile men, ages 25-50

Not indexed on PubMed

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Summary of Findings:

  • An unspecified color of maca was taken for 12 weeks by infertile men at a dose of 3,000 mg per day.

  • The group taking maca experienced:

  • Improvements in sperm motility (p<0.0001), vitality (p<0.01) and morphology (p<0.01), immature germ cell (p<0.01)

  • No changes in hormone levels were observed.

Note: Article is in Spanish, details retrieved from English abstract. 

December 2009

A pilot investigation into the effect of maca supplementation on physical activity and sexual desire in sportsmen

Human study, N=8, experienced endurance male athletes

PMID: 19781622

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Summary of Findings:

  • An unspecified maca extract was taken at a dose of 2,000 mg per day. 

  • Maca extract significantly improved 40 km cycling time performance compared to the baseline test (P=0.01), but not compared to the placebo trial after supplementation (P>0.05). 

  • Maca extract significantly improved the self-rated sexual desire score compared to the baseline test (P=0.01) and compared to the placebo trial after supplementation (P=0.03).

April 2009

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.

Human study, N=50, men with mild erectile dysfunction

PMID: 19260845

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Summary of Findings:

  • Unspecified color of maca was taken for 12 weeks in a dose of 1,200 mg twice daily

  • Both the placebo group and maca group reported significant improvements,

  • The maca group experienced more significant effects after 12 weeks of treatment including:

  • International Index of Erectile Function (IIEF-5) score (p < 0.001)

  • Improvement in psychological performance-related Satisfaction Profile (SAT-P) score, (p< 0.05).

  • Only maca-treated patients experienced a significant improvement in physical and social performance-related SAT-P score compared with the baseline (p< 0.05).

November-December 2008

Beneficial effects of Lepidium meyenii (Maca) on psychological symptoms and measures of sexual dysfunction in postmenopausal women are not related to estrogen or androgen content

Human study, N=16, post-menopausal women, 50-60 yo

PMID: 18784609

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Summary of Findings:

  • Unspecified color of maca was taken for 12 weeks in a dose of 3.5 grams of maca powder one time per day

  • No estrogenic or androgenic activity was detected in the maca used for the study.

  • Significant reduction (p<0.05, 30%) in symptoms as rated by Greene Climatic Scale, including decreased anxiety and depression and improved sexual function (p<0.05)

  • No differences were seen in serum concentrations of estradiol, follicle-stimulating hormone, luteinizing hormone, and sex hormone-binding globulin. 

  • Post hoc analyses revealed significant increase in estradiol would only be detected at a 30% increase.

August 2008

A double-blind, randomized, pilot dose-finding study of maca root (L. meyenii) for the management of SSRI-induced sexual dysfunction

Human study, N=20 men and women, with major depressive disorder

PMID: 18801111

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Summary of Findings:

  • Unspecified color of maca was taken at either 1.5 g/day (low dose) or 3.0 g/day (high dose)

  • Both groups had significant improvement in mean ASEX and MGH-SFQ score. 

  • For the group taking 3 g/ day

  • An increased improvement in sexual function was observed compared to the low dose groups, as measured by ASEX (p=0.028) and MGH-SFQ (p=0.017)

  • Significant improvement in libido (P<0.05), with increased sexual attempts (p=0.048) and enjoyment (p=0.019)

  • Small but significant decrease in depressive symptoms (p=0.047)

ASEX= Arizona Sexual Experience Scale; MGH-SFQ = Massachusetts General Hospital Sexual Function Questionnaire

July 2006

Lepidium meyenii (Maca) reversed the lead acetate induced -- damage on reproductive function in male rats

Animal study, male rats

PMID: 16510228

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Summary of Findings:

  • Maca protected spermatogenesis and increased epididymal sperm count. 

  • Maca administration reduced the deleterious effect on daily sperm production caused by lead acetate (LA) treatment. 

  • Maca prevented LA-induced spermatogenic disruption in rats and it may become in a potential treatment of male infertility associated with lead exposure.

April 2006

Effect of ethanol extract of Lepidium meyenii Walp. on osteoporosis in ovariectomized rat

Animal study, ovariectomized rats

PMID: 16466876

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Summary of Findings:

  • An extract of an unspecified color of maca was given for 28 weeks in two doses (0.096 or 0.24 g/kg body weight) to ovariectomized rats.

  • "The findings derived from the basis of bone mineral density, biomechanical, biochemical and histopathological parameters indicated that higher dose of ethanol extract of Maca was effective in the prevention of estrogen deficient bone loss."

December 2002

Effect of Lepidium meyenii (MACA) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men

Human study, N=57, men, ages 21-56

PMID: 12472620

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Summary of Findings:

  • An unspecified maca extract was taken at a dose of either 1,500 mg or 3,000 mg per day

  • At week 8, the group treated with maca had a significant increase (40%) in sexual desire (p<0.008);

  • At week 12, the group treated with maca had a significant increase (42.2%) in sexual desire (p<0.006);

  • No differences in the effect were noted between the dosing groups.

  • No changes in hormone levels (testosterone or estradiol) or mood (depression/anxiety) were observed.

December 2001

Lepidium meyenii (Maca) improved semen parameters in adult men

Human study, N=9, men

PMID: 11753476

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Summary of Findings:

A dose of 1,500 or 3,000 mg of maca was taken daily by men.

Maca increased: 

  • Seminal volume

  • Sperm count per ejaculation

  • Motile sperm count

  • Sperm motility

Dose did not impact the outcomes. 

April 2000

Effect of a lipidic extract from lepidium meyenii on sexual behavior in mice and rats

Animal study, male and female mice and rats

PMID: 10736519

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Summary of Findings:

  • Two formulas of unspecified colors of maca, called M-01 and M-02 were used. 

  • M-01 contained more polysaccharides and less macaenes and macamides compared to M-02.

  • "Oral administration of M-01 and M-02 enhanced the sexual function of the mice and rats, as evidenced by an increase in the number of complete intromissions and the number of sperm-positive females in normal mice, and a decrease in the LPE in male rats with erectile dysfunction."

  • "The present study reveals for the first time an aphrodisiac activity of L. meyenii, an Andean Mountain herb."

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