Human Studies
Combination of colors
Combining maca colors has been documented in the literature, most extensively as a formulation known as Maca-GO. The research suggests that this proprietary combination of black, yellow, purple, and red maca supports:
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Hormone health
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Bone health
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Adrenal health
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Cardiometabolic health
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Menopausal symptoms
Another combination of black, red, and yellow maca, known as MACAXS has been shown to impact testosterone levels in animals, though this is limited to one study.
Below is a compilation of the available human studies for a combination of maca colors with a comprehensive overview of the study details provided.
Feeding hydroalcoholic extract powder of Lepidium meyenii (maca) increases serum testosterone concentration and enhances steroidogenic ability of Leydig cells in male rats
About the Study
Type of study: Animal study, 6 weeks
Population: 8-week-old male rats, Wistar strain
Aim of the study: To examine whether feeding the hydroalcoholic extract powder of maca affects weight of the reproductive organs, serum concentrations of testosterone and luteinizing hormone (LH), number and cytoplasmic area of immunohistochemically stained Leydig cells, and steroidogenesis of cultured Leydig cells.
Maca Details
Species: Lepidium meyenii
Source of maca: TOWA CORPORATION K. K., Tokyo, Japan
Location where maca was grown: Not stated
Agricultural methods used: Not stated
Part of maca used: Dried bulbs of red, yellow, and black maca
Form of maca: Hydroalcoholic extract powder, known as MACAXS
Dose: Added to daily diet as a pellet, standardized to a nutritional profile of 6% protein, 0.7% lipid, 88% carbohydrate, 2.4% ash, and 2.1% water
Outcomes
Results:
Experiment #1:
Body weight increased in both groups.
Weight of the testis and ventral prostate did not differ between the treated and control group.
Weight of the seminal vesicles significantly increased in the maca fed group.
Testosterone levels were significantly increased in the maca group at 14 weeks of age, compared to the control group. No differences in LH were observed.
The number of Leydig cells nuclei did not differ between the two groups.
Experiment #2
Cultured Leydig cells showed increase testosterone production in the maca fed group (p<0.05).
Hormone-Balancing Effect of Pre-Gelatinized Organic Maca (Lepidium peruvianum Chacon): (I) Biochemical and Pharmacodynamic Study on Maca using Clinical Laboratory Model on Ovariectomized Rats
About the Study
Type of study: Animal study
Population: Male and female mice, Swiss strain, 18-22g body weight and male and female Wister rats, 180-220g body weight to assess toxicity; sexually experienced female ovariectomized Wister rats to assess ovarian dysfunction.
Aim of the study: 1) To determine the acute toxicity of Maca-GO after single oral application (by intubations) in mice and rats. 2) To determine the pharmacodynamic assessment of chronic application of Maca-GO to laboratory animals with surgically-induced ovarian dysfunction.
Maca Details
Species: Lepidium peruvianum Chacon
Source of maca: Not stated
Location where maca was grown: Junín, Peru
Agricultural methods used: Sun dried, gelatinized (proprietary extrusion process without chemical treatment)
Part of maca used: Root
Form of maca: Powder, referred to as Maca-GO
Dose: Varied based on experiment
Outcomes
Results:
Toxicity:
LD50 toxicity test demonstrated that >15 g/kg of body weight in mice and > 5 g/kg body weight in rats (the highest doses used in the study), did not result in any adverse effects. This is a much higher dose than would be administered in humans suggesting maca would not pose safety concerns for human consumption.
Ovarian Dysfunction:
In ovariectomized rats, a reduction in estradiol, progesterone, cortisol, and ACTH levels were observed (p<0.05). No changes in cortisol or ACTH was observed in sham operated animals.
In rats with functioning ovaries, a reduction in estradiol and an increase in progesterone was observed. (250mg/kg BW for 4 weeks)
Ovariectomy resulted in lower TSH concentration and increased T3 levels. Maca-GO treated groups were able to counteract those changes.
Maca-GO treated groups demonstrated anti-depressant effects and improvements in cognitive function.
A slight reduction in total cholesterol and triglycerides was observed after 4 weeks of Maca-GO administration.
Long-term feeding of hydroalcoholic extract powder of Lepidium meyenii (maca) enhances the steroidogenic ability of Leydig cells to alleviate its decline with ageing in male rats.
About the Study
Type of study: Animal study, 24 weeks
Population: 7 or 11-week-old male rats, Wistar strain
Aim of the study: To examine whether feeding hydroalcoholic extract of Lepidium meyenii (maca) to two ages groups of male rats affects serum testosterone concentration and testosterone production by Leydig cells cultured with hCG, 22R-hydroxycholesterol or pregnenolone.
Maca Details
Species: Lepidium meyenii
Source of maca: Not stated
Location where maca was grown: TOWA CORPORATION K. K., Tokyo, Japan
Agricultural methods used: Not stated
Part of maca used: Dried bulbs
Form of maca: Hydroalcoholic extract powder, known as MACAXS
Dose: Not stated, added to the diet
Outcomes
Results:
Serum testosterone levels were significantly higher is the maca fed group at 14 weeks of age (p<0.05)
In younger rats, testosterone production by Leydig cells increased when cultured with 22R-hydroxycholesterol and pregnenolone, though not significantly. Whereas testosterone production by Leydig cells in older rats significantly increased with cultured with 22R-hydroxycholesterol (p<0.05).
Testosterone production by Leydig cells significantly increased (p<0.05) when cultured with hCG in the younger rats but not the older rats.
“Feeding the maca extract to 18-week-old rats for 30 weeks (48 weeks of age) alleviated the decline of testosterone production with ageing, but not to the level of the control group at 35 weeks of age.”
Concentrated Gelatinized Proprietary Phenotype Formulation of Lepidium peruvianum (maca) Positively Impacts Polycystic Ovarian Syndrome (PCOS), Premenstrual Syndrome (PMS), Dysmenorrhea, and Hormone Levels for Fertility Optimization: A Case Report
About the Study
Type of study: Human Case Report
Population: N=1, 31-year-old Caucasian female, medical diagnosis of polycystic ovarian syndrome (PCOS) and premenstrual syndrome (PMS)
Aim of the study: To report on improvements experienced by one woman using a concentrated gelatinized proprietary phenotype formulation of maca for PCOS, PMS, dysmennorhea, and hormone balancing for fertility optimization.
Maca Details
Species: Lepidium peruvianum
Source of maca: Femmenessence MacaHarmony, purchased from Symphony Natural Health, Inc.
Location where maca was grown: Not stated
Agricultural methods used: Not stated
Part of maca used: Not stated
Form of maca: Capsules
Dose: 500 mg twice daily capsules taken upon waking and mid-afternoon and transitioned to 1,000 mg once daily, taken upon waking, for improved compliance.
Outcomes
Results:
In 3 months and sustained for over 2 years:
Normalization of menstrual frequency (28-32 days)
Resolution of ovulation pain and cramping
Improved ovulation evidenced by increased cervical mucus and libido
Decreased/resolved PMS duration and intensity of symptoms
Decreased menstrual flow
Decreased menstrual cramping
Hormone balancing evidence by reduction in LH, normalization of LH/FSH ratio, and reduction in estradiol levels to support optimal levels for fertility.
Other details:
Over 2 years of care was included
When the patient stopped taking the maca formulation, symptoms worsened.
No adverse effects were experienced when taking maca
Additional supplements included vitamin D, prenatal vitamin and fish oil.
Short and long-term physiological responses of male and female rats to two dietary levels of pre-gelatinized maca (lepidium peruvianum chacon)
About the Study
Type of study: Animal study, 28 and 90 days
Population: 12-week-old male and 9-week-old female rats, Sprague-Dowley strain, N=90
Aim of the study: To identify physiological responses of male and female rats to either a short- or long-term administration of two doses of Maca (Lepidium peruvianum) and observe relationships which may exist between groups of hormones and effects mediated by them.
Maca Details
Species: Lepidium peruvianum Chacon
Source of maca: Not stated
Location where maca was grown: Junín, Peru
Agricultural methods used: Traditional drying methods-three months of drying at high altitude, gelatinized (proprietary extrusion process without chemical treatment)
Part of maca used: Root/hypocotyl
Form of maca: Powder, referred to as Maca-GO
Dose: Trial I (28 days): 0.75 and 7.5 g/kg BW; Trial II (90 days): 0.75 and 7.5 g/kg BW
Outcomes
Results:
Trial I: 28 days
A significant reduction on body weight for male rats (p<0.001) at the high dose
A significant increase in white blood cell and lymphocytes counts (p<0.001) at the low dose.
A significant increase in lymphocyte counts, relative red cell decomposition index, and average volume of red blood cells (p<0.05) at the high dose.
Significant decrease in cortisol levels with the low dose (p<0.001) and high dose (p<0.01).
Significant decrease in triglycerides (p<0.05) with the high dose.
Significant increase in estradiol levels (p<0.01) with the high dose.
No histological changes were observed in either group.
Trial II: 90 days
Both doses resulted in less weight gain for females and males compared to the control groups.
No significant changes in blood morphology were observed with either dose.
Significant decrease in cortisol with the low dose (p<0.05).
Significant increase in blood glucose levels in female rats with the high dose (p<0.01).
Significant increase in progesterone in female rats the high dose (p<0.05).
No histological changes were observed in either group.
An integrative approach for improving and managing premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD): A case report
About the Study
Type of study: Human Case Report
Population: N=1, 30-year-old Caucasian female, medical diagnosis of Premenstrual Dysphoric Disorder (PMDD) and premenstrual syndrome (PMS)
Aim of the study: To report on improvements experienced by one woman using a combination of therapies (Lepidium peruvianum, bioidentical progesterone therapy, and magnesium) for premenstrual headaches, menstrual cramping and flow, and intense psychiatric symptoms associated with a diagnosis of PMDD.
Maca Details
Species: Lepidium peruvianum
Source of maca: FemmenessencePRO Harmony, purchased from Symphony Natural Health, Inc.
Location where maca was grown: Not stated
Agricultural methods used: Not stated
Part of maca used: Not stated
Form of maca: Not stated
Dose: 500 mg once daily to 1,000 mg twice daily oral administration, capsules, taken upon waking and mid-afternoon
Outcomes
Results:
In 3 months:
Resolution of severe emotions (depression with ruminating negative thoughts and suicidal ideation) experienced in the luteal phase of the menstrual cycle
Resolution of premenstrual headaches and fatigue
Resolution of menstrual cramping
Decreased menstrual flow
LH reduced to normal levels, resulting in a normal FSH/LH ratio
Other details:
Treatment included bioidentical progesterone therapy (for some of the months reported) and magnesium supplementation
Improvements were reported to be maintained for three months without hormone therapy
No adverse effects were experienced
Improvements in premenstrual syndrome, primary dysmenorrhea, and menorrhagia with natural therapies: A case report
About the Study
Type of study: Human Case Report
Population: N=1, 39-year-old Caucasian female
Aim of the study: To report on improvements experienced by one woman for PMS, dysmenorrhea, and menorrhagia
Maca Details
Species: Lepidium peruvianum
Source of maca: FemmenessencePRO Harmony, purchased from Symphony Natural Health, Inc.
Location where maca was grown: Not stated
Agricultural methods used: Not stated
Part of maca used: Not stated
Form of maca: Not stated
Dose: 500 mg bid, oral administration, capsules, taken upon waking and mid-afternoon
Outcomes
Results:
In four months, the patient experienced resolution of multiple PMS symptoms, including balanced moods, improved satiety, reduced cystic acne, and regulated bowel movements, as well as complete resolution of dysmenorrhea (menstrual pain and cramping), resolution of menorrhagia (as detailed by lighter menstrual cycles).
Other details:
Was used in combination with Medicago sativa and magnesium.
No adverse effects were experienced.
Nutritional management of surgically induced menopause: A case report
PMID: 34253105
About the Study
Type of study: Human Case Report
Population: N=1, 32-year-old post-menopausal Caucasian woman (hysterectomy and oophorectomy)
Aim of the study: To report on improvements experienced in one woman for eliminating post-menopausal symptoms.
Maca Details
Species: Lepidium peruvianum
Source of maca: Femmenessence MacaPause (Maca-GO®), purchased from Symphony Natural Health
Location where maca was grown: Not stated
Agricultural methods used: Not stated
Part of maca used: Not stated
Form of maca: Not stated
Dose: 1,000 mg bid, oral administration, capsules, taken upon waking and mid-afternoon
Outcomes
Results:
Resolution of hot flashes and anxiety in two months, improved mood and sleep, as measured by the Kupperman’s Menopausal Index (KMI)
Other details:
No adverse effects were experienced.
Hormone-balancing effect of pre-gelatinized organic maca (Lepidium peruvianum Chacon): (III) Clinical responses of early-postmenopausal women to maca in double blind, randomized, placebo-controlled, crossover configuration, outpatient study
About the Study
Type of study: Human study, Two trials: Trial 1: Four month, double-blind, randomized, outpatient, four months crossover design clinical trial [2 month of treatment and 2 months of placebo]; Trial 2: Inclusion of Trial 1 plus a pilot bone density observation
Population: N=34 Caucasian early postmenopausal women, 49-58 years old (Trial 1: N=22; Trial 2: N=12)
Aim of the study: Trial 1: To assess effectiveness of maca parallel to placebo on hormones and menopausal symptoms; Trial 2: To assess effectiveness of maca parallel to placebo on hormones and menopausal symptoms and observe bone density markers
Maca Details
Species: Lepidium peruvianum
Source of maca: Maca-GO®
Colors of maca: Black, purple/red, and yellow proprietary combination
Location where maca was grown: Junín, Peru (4,200 and 4,500 meters above sea level)
Agricultural methods used: Cultivated, harvested, dried (3 months of air drying) on the plantation site of Junín, using traditional methods
Part of maca used: Hypocotyls/roots
Form of maca: Gelatinized, standardized, no chemicals used, maca root powder in capsules
Dose: 1,000 mg bid, oral administration, capsules, 30 minutes before morning and evening meals
Outcomes
Results:
Trial 1: Maca-GO® group experienced:
Significant decrease in BMI and LH levels (p<0.05)
Significant increase in E2 (P<0.05)
Significant reduction in T3, cortisol, ACTH (p<0.05)
Significant increase in serum iron and plasma calcium levels (p<0.05)
Significant decrease in menopausal symptoms (p<0.001)
Trial 2: Maca-GO® group experienced:
An increase in forearm bone density in 4 months, whereas the placebo group had a reduction in bone density during the same time.
An increase in E2
A decrease in FSH
Abbreviations: ACTH: adrenocorticotropic hormone; BMI: body mass index; E2: estradiol; FSH: follicle-stimulating hormone; LH: luteinizing hormone; T3: triiodothyronine
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
About the Study
Type of study: Human study, two trials, conducted at four clinics
Trial 1: 3-month double blind, randomized, coordinated multi-center, outpatient clinical study
Trial 2: 4-month double blind, randomized, coordinated multi-center, outpatient clinical study
Population: N=168 Caucasian, healthy, early menopausal women, 49-58 years old
Trial 1: N=102 (N=88 completed); Trial 2: N=66 (N=40 completed)
Aim of the study: Trial 1: To confirm findings of pilot study; Trial 2: To assess placebo effect when maca is introduced in different sequence and length intervals.
Maca Details
Species: Lepidium peruvianum
Source of maca: Maca-GO®
Colors of maca: Black, purple/red, and yellow proprietary combination
Location where maca was grown: Junín, Peru (4,200 and 4,500 meters above sea level)
Agricultural methods used: Cultivated, harvested, dried (3 months of air drying) on the plantation site of Junín, using traditional methods
Part of maca used: Hypocotyls/roots
Form of maca: Gelatinized, standardized, no chemicals used, maca root powder in capsules
Dose: 1,000 mg bid, oral administration, capsules, 30 minutes before morning and evening meals
Outcomes
Results:
Trial 1
Significant increase in E2 (P<0.001)
Significant decrease in FSH (p<0.05)
Significant increase in HDL levels (p<0.05)
Significant decrease in menopausal symptoms in one month (p<0.001) of treatment and further reduction in the second month of treatment, followed by an increase of symptoms when returning to placebo (p<0.001).
Trial 2
Significant decrease in FSH and LH (p<0.05)
Significant increase in E2 (p<0.05)
Significant reduction in menopausal symptoms (p<0.001)
Abbreviations: E2: estradiol; FSH: follicle-stimulating hormone; LH: luteinizing hormone
Therapeutic effects of pre-gelatinized maca (Lepidium Peruvianum Chacon) used as a non-hormonal alternative to HRT in perimenopausal women - clinical pilot study
About the Study
Type of study: Human study, four months, double blind, crossover, randomized pilot trial [2 months of placebo and 2 months of Maca-GO®
Population: N=20, Caucasian, healthy, menstruating women, 41-50 years old (2 did not complete the study)
Aim of the study: Measure the effects Maca-GO®on hormones and alleviation of symptoms contributing to menopausal discomfort in perimenopausal women.
Maca Details
Species: Lepidium peruvianum
Source of maca: Maca-GO®
Colors of maca: Black, purple/red, and yellow proprietary combination
Location where maca was grown: Junín, Peru (4,200 and 4,500 meters above sea level)
Agricultural methods used: Cultivated, harvested, dried (3 months of air drying) on the plantation site of Junín, using traditional methods
Part of maca used: Hypocotyls/roots
Form of maca: Gelatinized, standardized, no chemicals used, maca root powder in capsules
Dose: 1,000 mg bid, oral administration, capsules, 30 minutes before morning and evening meals
Outcomes
Results:
After two months of use
95% of women involved in the study had improvements in menopausal symptoms as assessed by Kupperman’s Menopausal Index.
Significant reduction in body weight, systolic and diastolic blood pressure (p<0.05)
Significant increase in HDL (p<0.01) and iron (p<0.05) levels
Significant reduction in menopausal symptoms: hot flashes, excessive sweating, interrupted sleep (all at p<0.01), nervousness, depression, heart palpitation (all at p<0.05)
Significant increase in E2, FSH, and PG (all at p<0.01)
Significant reduction in ACTH (p<0.05)
Other details:
Authors state the active constituents of Lepidium peruvianum including sterols, macaenes, macamides, glucosinolates, and alkaloids help support the regulation of ovarian function.
Authors acknowledge that dosing needs can vary for each woman.
Abbreviations: ACTH: adrenocorticotropic hormone; E2: estradiol; FSH: follicle-stimulating hormone; LH: luteinizing hormone; PG: progesterone
Use of gelatinized maca (lepidium peruvianum) in early postmenopausal women.
About the Study
Type of study: Human study, double-blind, placebo-corrected clinical pilot study conducted in two separate trials: Trial 1 was for three months, and Trial 2 was for nine months
Note:
The 3-month study included 1 month of placebo, followed by 2 months of Maca-GO®
The 9- month study included 1 month of placebo, followed by 8 months of Maca-GO®
Population: N=20 Caucasian, healthy, early post-menopausal women, 45-62 years old, 8 subjects did not complete the trial.
Aim of the study: Determine the effect of Maca-GO® on alleviating symptoms of menopausal discomfort experienced by women in early post menopause as measured by profiles of serum hormones and Greene's Menopausal Index.
Maca Details
Species: Lepidium peruvianum
Source of maca: Maca-GO®
Colors of maca: Black, purple/red, and yellow proprietary combination
Location where maca was grown: Junín, Peru (4,200 and 4,500 meters above sea level)
Agricultural methods used: Cultivated, harvested, dried on the plantation site of Junín, organic status
Part of maca used: Hypocotyls/roots
Form of maca: Gelatinized, standardized, no chemicals used, maca root powder in capsules
Dose: 1,000 mg bid, oral administration, capsules, 30 minutes before morning and evening meals
Outcomes
Results:
In 2 and 8 months
A significant decrease in FSH (P<0.05)
A significant increase in LH (P<0.05)
Significant reduction in menopausal symptoms in 2 and 8 months (p<0.05)
In month 8
A significant increase in E2 and PG (P<0.05)
Other details:
Authors state that active constituents of Lepidium peruvianum include sterols, macaenes, macamindes, glucosinolates, and alkaloids may be the reason for the improvements.
Abbreviations: E2: estradiol; FSH: follicle-stimulating hormone; LH: luteinizing hormone; PG: progesterone