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Eighty-five percent of peri- and postmenopausal women experience various menopausal symptoms, including, but not limited to, hot flashes, night sweats, sleep disturbances, mood imbalances, loss of libido, weight gain, and vaginal dryness (1). The significant loss of hormones, particularly in post-menopause, also contributes to changes in bone and cardiometabolic health (2).


There is conflicting data reported in the literature regarding maca’s impact on hormones. This may be due to the lack of consistency in reporting the phenotypes (colors) and doses of maca used in research studies.


Animal studies


One animal study of ovariectomized rats suggests that maca can modulate hormone levels. However, the exact mechanism is not well understood and may be due to one or more of the phytochemicals present in maca. Using an ethanol extract of L. meyenii (the color is not specified) in a low and high dose, researchers found a significant increase in estradiol 28 weeks following the ovariectomy using the low dose, with no significant difference in estradiol (E2) levels using a high dose. These changes were not observed at 12 weeks, suggesting longer-term use may be warranted. Follicle-stimulating hormone (FSH) was significantly decreased (p<0.01) with both doses at 28 weeks (3).


While not specific to peri and post-menopause, another animal study fed female rats 5%, 10%, or 50% of an unspecified color of dried maca powder for seven weeks. A 4.5-fold increase (P<0.01) in luteinizing hormone (LH) and a 19-fold increase (P<0.01) in FSH were observed in rats fed with 50% Maca powder, providing additional insight into the hormonal effects of maca (4).



Human Studies


In one pilot study, postmenopausal Chinese women took 3.3 g daily of an unspecified color of maca known commercially as Maca Power for six weeks. They did not experience any changes in E2, FSH, or LH, with the authors suggesting that maca does not exert a hormonal effect. However, improvements in diastolic blood pressure were observed, and a 34-36% decrease in depression and anxiety was reported as measured by the Women’s Health Questionnaire Scale. Similarly, up to a 30% reduction in menopausal symptoms was observed using the Greene Climacteric Scale. Of interest, the authors noted that there may be various cultural aspects as it relates to symptoms experienced by Chinese women compared to Caucasian women, including genetics, diet, and less reporting of symptoms. In fact, only 5-10% of Asian women report vasomotor symptoms (5).


A 12-week, randomized, double-blind, placebo-controlled, crossover trial (six weeks of maca and six weeks of placebo) in postmenopausal women using the same product, Maca Power, experienced a significant (p<0.05) decrease in menopausal symptoms as assessed by the Greene Climacteric Scale, including reductions in anxiety, depression, and improvements in sexual function. No differences were seen in serum concentrations of E2, FSH, LH, and sex hormone-binding globulin (SBHG). However, post hoc analyses revealed a significant increase in estradiol would only be detected at a 30% increase. The authors concluded that no estrogenic or androgenic activity was detected in this study (6).


A product known as Maca-BG1.2TM, which is not currently available as a commercial product, resulted in a 2.2-fold increase in E2 levels in healthy, perimenopausal Japanese women in 8 weeks, although this was not statistically significant. Further analysis revealed serum E2 levels in the perimenopausal subjects with regular menstruation cycles displayed the most relevant change. Women experienced a marginal decrease in insomnia and hot flashes and those with mild symptoms achieved the greatest improvements in reducing menopausal symptoms. Of note, the dose of Maca-BG1.2TM was 300 mg/day, which is considerably lower than doses reported in other studies and the color(s) of maca in this product are unknown (7).


A cross-sectional, population-based study comparing individuals who consumed maca as a food source to those who did not, found that regular maca consumers had higher serum estradiol levels (p<0.01) and lower testosterone/estradiol ratios (p<0.05) (8).


Lepidium peruvianum as a proprietary formulation (Maca-GO®)


Of the colors of maca researched, a concentrated gelatinized proprietary phenotype formulation of Lepidium peruvianum containing a combination of black, yellow, purple, and red maca, known as Maca-GO® been extensively studied for its positive impact on hormone health, particularly in peri- and postmenopausal women. This maca formulation is described as a standardized, concentrated, bioavailable, organic, gelatinized (98.5–99.8%) formulation, using a specific ratio of maca (L. peruvianum) phenotypes (black, yellow, purple, and red) cultivated in Junín region of Peru and processed using traditional drying methods (9).


Animal Studies

Meissner et al. conducted research using Maca-GO® in two animal studies to identify physiological responses and to assess safety (10,11).


The first study (10) used male and female rats in two doses: a low dose of 0.75 g/kg and a high dose of 7.5 g/kg body weight.


Key findings included:

  1. Significant decrease in cortisol levels (p<0.001) with the low and high doses.

  2. The high dose significantly increased estradiol levels (p<0.01). 

  3. Long-term use (90 days) of the high dose resulted in increased progesterone levels. 


The second animal study (11) used ovariectomized rats to assess various effects of Maca-GO® systemically. Maca-GO® significantly reduced the glucocorticosteroid hormones. ACTH and cortisol. It was observed that thyroid stimulating hormone (TSH) was decreased following the ovariectomy and was restored to comparative levels to the non-ovariectomized rats following the administration of Maca-GO®.  Additionally, the control rats (with ovaries) experienced an increase in T3 levels, while T4 levels significantly decreased upon administration of Maca-GO®. 


This study (11) also explored the toxicity levels of Maca-GO® in both mice and rats. It is reported that the toxicity was > 15 g/kg of body weight in mice and > 5 g/kg body weight in rats, which is above the 2 g/kg body weight limit set for dietary supplements for human consumption. Further, no adverse effects were detected in test animals. Safety testing was conducted following the Organization for Economic Cooperation and Development (OECD) protocol for acute toxicity of chemical substances.


Human Trials

Meissner et al. have also conducted four human clinical trials using Maca-GO® for peri- and postmenopausal women. Combined,195 women participated in the clinical trials (9,12–14).


Two pilot studies were conducted; one included perimenopausal women (9) and one included early postmenopausal women (12). Both studies aimed to assess the use of Maca-GO for alleviating menopausal symptoms (using Greene’s Menopausal Score or Kupperman’s Menopausal Index) and its impact on hormones and cardiovascular markers.


Twenty perimenopausal women (ages 41-50) were enrolled for a 4-month double-blind, crossover, randomized pilot study (9). Women were assigned to two groups receiving either:

  • 2 months of placebo (sorbitol & cellulose), followed by 2 months of Maca-GO® (2 g/day) OR

  • Two months of Maca-GO® (2 g/day) followed by two months of placebo


After two months of Maca-GO® a significant increase in E2 (p<0.05), FSH (p<0.05), Progesterone (p<0.01), and ACTH (p<0.05) was observed. Additionally, a significant decrease in menopausal symptoms was experienced as assessed by Kupperman’s Menopausal Index (74-87% reduction), with the most improvements noted as reducing hot flashes, night sweats, heart palpitations, nervousness, disrupted sleep, and depression (9).


The pilot study of postmenopausal women consisted of two trials (12). Twenty early menopausal women (ages 45-62) were enrolled in Trial I, in which Maca-GO® was taken for two months. Eight women (ages 45-62) were enrolled in Trial II, in which Maca-GO® was taken for eight months. Both groups began the trial by taking a placebo for one month. At the conclusion of this study, women experienced a significant increase in


  • LH after two months and eight months of use

  • Progesterone after eight months of use

  • Estradiol after two months and eight months of use


Additionally, there was a significant decrease in FSH after two months and eight months of use. Seventy-five percent (75%) of women reported noticeable reductions in menopausal symptoms, as assessed by Greene’s Menopausal Score, with scores reducing significantly.


Two additional clinical studies were conducted (13,14) using Maca-GO® in early postmenopausal women.


One study (13) included early postmenopausal Caucasian women (ages 49-58) enrolled in a European multi-center clinical trial. This study aimed to confirm the pilot studies' results and assess biological markers and symptomatic relief from menopausal symptoms when Maca-GO® (2 g/day) and placebo were introduced in various sequences and for various lengths of time. This approach was chosen to generate a broad set of data to confirm the outcome of the pilot studies, assess residual effects of Maca-GO® switching to placebo, and identify placebo effects in symptom relief as well as changes in biological markers under more expanded, diverse, real-world settings.


Key findings include:

  • Significant increase in E2 after two months of Maca-GO®  following one and two months of placebo.

  • Significant increase in E2 after two months of Maca-GO®  followed by a decrease in E2 when women were switched to placebo for one month, and a subsequent increase of E2 when resuming Maca-GO® for one month.

  • The increase in progesterone (P) after two months of Maca-GO® was followed by a decrease in P when women were switched to a placebo in the third month.

  • Significant decrease in menopausal symptoms as assessed by Kupperman’s Menopausal Index after two months of Maca-GO® with an increase of symptoms occurring with the administration of placebo.


Another clinical trial included the enrollment of 34 early postmenopausal Caucasian women (ages 49-58 years old). This study included two trials, of which 22 women were admitted into the crossover configuration trial and 12 women in a pilot bone density observation.


Key findings include:

  • Significant increase in E2 after two months of Maca-GO®  following two months of placebo.

  • Significant decrease in LH after two months of Maca-GO® following two months of placebo.

  • Increase in E2 after 1-3 months of Maca-GO® compared to placebo, in which levels remained relatively constant.

  • The increase in progesterone (P) after two months of Maca-GO® followed by a decrease in P when women were switched to a placebo in the third month.

  • Significant decrease in menopausal symptoms as assessed by Kupperman’s Menopausal Index, after two months of Maca-GO®. By comparison, the placebo group experienced increased symptoms in 2 months. For the group who transitioned to placebo following the use of Maca-GO®, symptoms returned upon stopping Maca-GO®.

  • Total bone density scores improved in 4 months compared to placebo, which resulted in lower bone density scores in the same time frame.


Maca-GO® has also been reported in several case studies for women in the premenopausal (reproductive) stage of life. At present, this combination of maca phenotypes provides the most human studies (8) compared to the available research on black, red, yellow, and purple phenotypes, with the caveat that 15 human studies do not state the colors used.


Author: Kim Ross, DCN

Reviewer: Mona Fahoum, ND

Last Updated: February 13, 2024


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