The infertility caused by impaired spermatogenesis and semen parameters is a public health problem which has become an issue of great concern. As long as current therapeutic management is often associated with side effects and no significant efficacy [
Twenty apparently healthy men were treated with maca or placebo for 12 weeks in order to evaluate its effect on semen parameters and serum hormone levels. In particular we have monitored five reproductive hormones (luteinizing hormone, follicle-stimulating hormone, prolactin, estradiol, and testosterone), two thyroid hormones (free thyroxin and thyroid-stimulating hormone), and semen parameters (total sperm count, sperm concentration, morphology, and motile sperm count) to evidence the effects of maca supplement on the mentioned parameters. As recommended by previous studies [
Twenty healthy men of 20–40 years were included in the study. They were nonsmokers and at least 3 months before and during the study did not use hormonal treatment, anabolics, or any medical substances which could change their serum hormone levels. All the participants signed agreements to be involved in the study after being informed of its purpose, possible benefits, and risks and approval from an independent Ethics Committee was obtained.
Using a prospective, randomized, placebo-controlled, double-blind design [
Gelatinized and powdered maca was provided by the Peruvian company Andean Roots SRL and delivered to the Czech Republic in 2012. The plant material, yellow type of maca, was harvested in the Cerro de Pasco region of the central Peruvian Andes at the altitude between 4200 and 4500 meters above sea level. During the gelatinization, original dried hypocotyls of maca were rehydrated and exposed to short-term elevated pressure under moist conditions. This standard process of sample preparation decomposed the starch component and increased the digestibility of the product; after gelatinization the sample was dried again to less than 7% humidity. The content of the six most abundant macamides, the quality markers of maca, was analyzed in gelatinized sample by HPLC-UV following the methodology previously described [
To evaluate the effect of maca, this pilot study was designed as a 12-week, double-blind, placebo-controlled, randomized, parallel trial in which active treatment by gelatinized maca was compared to a placebo. Twenty men were randomly divided as previously described. Powder was dosed into the gelatin enterosolvent capsules, each of which contained 350 mg; the daily dose was five capsules, equal to 1.75 g. Semen samples were collected before, in the 6th and in the 12th week of the treatment. Samples of blood were collected before and after the trial.
The samples of semen were obtained by masturbation after 3 days of sexual abstinence and evaluated in the Assisted Reproduction Center Apolinar, Department of Obstetrics and Gynecology, 1st Faculty of Medicine, Charles University, and General Faculty Hospital in Prague. Seminal analysis was performed according to the guidelines of the World Health Organization [
Blood samples were collected on the same day as the semen samples. Five reproductive hormones (luteinizing hormone, follicle-stimulating hormone, prolactin, estradiol, and testosterone) and two thyroid hormones (free thyroxin and thyroid-stimulating hormone) were measured by routine immune-analytical methods in the Central Laboratory of General Faculty Hospital, 1st Faculty of Medicine, Charles University in Prague.
All the data were analyzed using Statistica 10 software. As homogeneity of variance assumptions were not satisfied in all cases, a nonparametric Mann-Whitney
From 20 volunteers, two men appeared to suffer from oligozoospermia; therefore, they had to be excluded from the trial. Out of 18 remaining volunteers, 7 consumed placebo and 11 maca.
Not any statistically significant differences between semen parameters in different collection dates as well as maca versus placebo groups were found. This could be due to higher within groups variation. We found, however, that all assessed quality parameters showed rising trends in the maca group after 12 weeks of the trial (Table
Mean semen parameter values during maca and placebo treatment (mean ± standard error; Kruskal-Wallis
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Normal sperm morphology (%) | Sperm concentration (×106 mL−1) | Progressively motile sperm count (×106 mL−1) | Motile sperm count (×106 mL−1) | Total sperm count (×106) | Semen volume (mL) | ||
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Maca | 0 weeks | 11 | 18.18 ± 1.68 | 77.27 ± 6.79 | 47.72 ± 4.33 | 58.00 ± 5.40 | 277.90 ± 31.18 | 3.66 ± 0.31 |
6 weeks | 11 | 22.22 ± 2.22 | 86.11 ± 7.48 | 51.66 ± 2.88 | 63.22 ± 3.47 | 241.11 ± 25.54 | 2.92 ± 0.33 | |
12 weeks | 11 | 22.00 ± 2.00 | 87.80 ± 9.86 | 56.20 ± 7.19 | 66.30 ± 8.36 | 332.31 ± 58.98 | 3.99 ± 0.31 | |
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Placebo | 0 weeks | 7 | 20.71 ± 1.70 | 106.71 ± 15.59 | 70.00 ± 12.53 | 83.42 ± 13.73 | 295.56 ± 69.580 | 2.77 ± 0.53 |
6 weeks | 7 | 23.33 ± 2.10 | 100.00 ± 10.24 | 60.00 ± 8.560 | 71.66 ± 8.620 | 395.16 ± 152.57 | 3.57 ± 1.01 | |
12 weeks | 7 | 17.85 ± 3.75 | 100.28 ± 12.04 | 65.71 ± 11.09 | 74.85 ± 11.43 | 355.28 ± 96.940 | 3.44 ± 0.64 | |
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Influence of maca treatment on sperm concentration.
Influence of maca treatment on motile sperm concentration.
Statistically significant difference in level of prolactin between the baseline of maca and placebo group was found; therefore, prolactin was not included in the hormonal analysis. No substantial changes of other hormone levels were observed in the blood serum after 12 weeks of maca or placebo administration (Table
Baseline and posttreatment serum level of hormones in maca and placebo-treated subjects (mean ± standard error; Mann-Whitney
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LH |
FSH |
Estradiol | Testosterone | fT4 |
TSH |
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(IU L−1) | (IU L−1) | (nmol L−1) | (nmol L−1) | (pmol L−1) | (mIU L−1) | |||
Maca |
0 weeks | 11 | 4.03 ± 0.50 | 4.40 ± 0.37 | 0.10 ± 0.01 | 19.92 ± 1.75 | 16.31 ± 0.29 | 2.35 ± 0.30 |
12 weeks | 11 | 2.90 ± 0.33 | 3.75 ± 0.37 | 0.10 ± 0.01 | 20.10 ± 2.24 | 16.91 ± 0.62 | 1.58 ± 0.23 | |
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Placebo |
0 weeks | 7 | 3.82 ± 0.50 | 4.46 ± 0.50 | 0.09 ± 0.01 | 19.43 ± 2.25 | 14.02 ± 0.68 | 2.92 ± 1.63 |
12 weeks | 7 | 2.99 ± 0.57 | 3.55 ± 0.64 | 0.11 ± 0.01 | 18.63 ± 2.15 | 15.28 ± 0.72 | 2.63 ± 1.38 | |
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The content of six main abundant macamides in maca powder is shown in Table
Content of the six most abundant macamides in maca powder (mg/g DW).
Macamide | Mean ± SE |
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Methoxy- |
0.12 ± 0.05 |
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1.02 ± 0.17 |
Methoxy- |
0.10 ± 0.01 |
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1.02 ± 0.16 |
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1.68 ± 0.29 |
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0.41 ± 0.08 |
We wish to evaluate maca’s semen quality enhancing properties by, to the best of our knowledge, the first double-blind, randomized, placebo-controlled trial in healthy men and to contribute to the current scientific evidence of this crop with a pronounced ethnopharmacological reputation. This pilot study appears to extend the knowledge of maca’s properties and supports several findings of previous studies. Our results showed rising trends of semen parameters after 12 weeks of maca administration and correlate with two previously conducted studies in men, which lacked any control group [
Maca’s semen enhancing properties have also been described in several scientifically rigorous studies in animals [
In order to demonstrate whether maca influences fertility on a hormonal basis, levels of selected hormones in blood serum were measured. We did not find any substantial changes in comparison to the baseline or a control group. These results reinforce previous studies in rats [
The mechanism of the fertility enhancing properties of maca remains unconfirmed, but some aphrodisiac activities have been related to its lipidic fraction [
From the viewpoint of trial design, the daily doses and the length of treatment would be expected to play a crucial role. Values in spermiograms of our volunteers showed rising trends between 6th week and 12th week of treatment. Thus, the fact that Gonzales et al. [
Hirsh [
Maca is touted as a potent over-the-counter (OTC) supplement. As long as men prefer to use OTC products to enhance fertility rather than prescribed medication or any medical intervention, it is worth continuing to assess its possible benefits [
The authors declare that there is no conflict of interests regarding the publication of this paper.
The authors thank Andean Roots SRL for providing maca powder and the Assisted Reproduction Center Apolinar and Central Laboratory at Department of Obstetrics and Gynecology, 1st Faculty of Medicine, Charles University, and General Faculty Hospital in Prague for seminal and hormonal analysis.