Table of Contents
- Current evidence position
- Key safety points
- Brad's videos on this topic
- Overview
- Forms and Bioavailability
- Evidence for Benefits
- Recommended Dosing
- Safety and Side Effects
- Drug Interactions
- Dietary Sources
- References
Current evidence position
Brad has not made a video on this topic; this is a summary of the evidence, not his view. In small randomized trials, gelatinized maca at 1,500 mg or 3,000 mg a day improved sexual desire in healthy men in a 12-week trial [23], and 3.5 g a day of maca powder for 6 weeks lowered anxiety, depression and sexual dysfunction scores in 14 postmenopausal women [26]; neither trial found changes in sex hormone levels. Systematic reviews call the evidence limited because the trials are few and small [54, 35], and a 2022 review of five trials found unclear effects on semen quality; its pooled analysis showed no clear rise in sperm concentration [55]. Safety data are thin: in one 90-day trial maca at 0.6 g a day raised the liver enzyme AST and diastolic blood pressure [42], a case report linked maca root powder to a rise in blood lead [58], and lab studies found estrogen-like activity [62] and faster migration of breast cancer cells [47].
Key safety points
- Lab studies found estrogen-like activity in breast cancer cells, and maca extract made triple-negative breast cancer cells migrate more [62, 47]. If you have a hormone-sensitive cancer or condition, talk to your doctor before using maca.
- Maca products can contain lead. One woman's blood lead rose after she began maca root powder and fell when she stopped; the authors warn women of childbearing age in particular [58].
- In a 90-day trial, maca at 0.6 g a day raised the liver enzyme AST and diastolic blood pressure [42]. LiverTox says maca has not been implicated in liver injury, though one case report followed a single drink of a maca liquor [66, 59]; if you have liver disease or high blood pressure, ask your doctor first.
- Maca contains glucosinolates, and some glucosinolates can affect the thyroid [7, 51]. If you have a thyroid condition or take thyroid medicine, ask your doctor first.
- A chart review reported restless legs with maca taken alongside the antidepressant mianserin [65]. If you take an antidepressant, ask your prescriber first.
- A report of two cases and a review of online reports link maca to psychotic symptoms, mood changes and anxiety [60, 61]. If you have bipolar disorder or a history of psychosis, ask your doctor first.
Brad's videos on this topic
None yet.
1. Overview
Maca (Lepidium meyenii) belongs to the Brassicaceae (cabbage and mustard) family and grows in the central Andes of Peru between 4,000 and 4,500 m [2]. It has been cultivated for more than 2,000 years [2]. The edible part is the underground storage organ, the hypocotyl [8].
Andean people use maca as food and medicine: the root is cooked, baked, fermented into a drink or made into porridge, and it is used as a tonic and fertility enhancer for people and cattle [39]. Its medicinal use was first recorded in the seventeenth century [4]. Online marketing has promoted it as "Peruvian Ginseng" for libido and fertility [39].
Maca's major constituents are starch, dietary fiber and protein [3]. It also contains essential amino acids, fatty acids, vitamin C, copper, iron and calcium [30].
Some of its compounds, such as macamides, are unique to maca [39]. Macamides are fatty acid N-benzylamides [5]. In lab tests, several macamides block fatty acid amide hydrolase (FAAH), an enzyme of the endocannabinoid system [5, 6]. Fresh roots contain almost no macamides; they form when the roots are dried [8]. Maca also contains the glucosinolates glucotropaeolin and m-methoxyglucotropaeolin, and a beta-carboline compound (MTCA, 1-methyltetrahydro-beta-carboline-3-carboxylic acid) [7]. Plant genetics, the part of the plant used and processing all change the chemical makeup of maca products [3].
Maca is promoted for libido, fertility, menopausal symptoms, erectile dysfunction and prostate enlargement [39]. A 2018 review concluded that these health claims cannot be fully supported; trials have been inconclusive, with weak methods and small samples [39]. Another review found clinical studies to support the claimed health effects lacking [3].
Exports of maca from Peru grew from USD 1,415,000 in 2001 to USD 6,170,000 in 2010 [2]. Maca is now also grown widely in China's Yunnan Province, and the surge in demand has had serious consequences for local producers in Peru [39].
2. Forms and Bioavailability
Root Color Varieties
Maca hypocotyls come in different colors, from white to black, and one research group has compared yellow, black and red maca [28]. Studies have found differences between them [9].
| Color | Findings in experimental studies |
|---|---|
| Yellow | Moderate effects on sperm production in rats [28]; larger litters in female mice [16] |
| Red | No effect on sperm production; reduced prostate size in rats [28, 14]; reversed experimentally induced osteoporosis [9] |
| Black | Best effects on sperm production, memory and fatigue [9, 28] |
Important caveat: These color differences come from experimental studies, mostly in animals [9, 28]. Red maca, but neither yellow nor black, reduced prostate size in rats [14]. Black maca raised sperm counts in rats within one day of starting treatment [15]. Yellow maca increased litter size in female mice [16].
Processing Forms
Raw maca powder: The dried root is ground into powder. Trials have tested maca powder [26] and maca tablets [32].
Gelatinized maca powder: Gelatinized maca was used in a trial in men [23, 52], and pre-gelatinized maca in trials in women around menopause [17, 34].
Maca extract: Trials have also used maca extracts [29, 25]. Results from one preparation may not apply to another; a toxicology review stressed the need for standardized quality [4].
Capsules: Capsules and tablets hold powder or extract. In the 2002 trial in men, doses were 1,500 mg or 3,000 mg a day [23].
Maca flour (harina de maca): Maca is sold as powder, capsules, pills, flour, liquor and extracts [28].
Bioavailability Considerations
The parts of maca that cause its effects are not known. Its effects have been ascribed to macamides and glucosinolates, but this cannot be confirmed for lack of data [39]. Data on how maca works are inadequate [4].
Gelatinized vs. raw powder: Both gelatinized and plain powders have been tested in trials [23, 26].
Powder vs. extract: Trials have used both powder and extract [26, 29].
Dose-form practical considerations: Trial doses run to several grams a day [26].
Growing Region and Quality Concerns
Maca is now grown outside the Andes, including in Yunnan Province in China, and farming has shifted to mass production with fertilisers and pesticides [39]. This may affect the chemistry of the plant and the quality, safety and efficacy of maca products [39]. One case report links maca root powder to raised blood lead [58].
3. Evidence for Benefits
Sexual Desire (Libido)
Sexual desire is the most studied use of maca. A 2010 systematic review found four small randomized trials and called the evidence limited [54].
Men:
A 12-week randomized, double-blind, placebo-controlled trial in men aged 21-56 tested gelatinized maca at 1,500 mg or 3,000 mg a day. Sexual desire improved from 8 weeks of treatment. Serum testosterone and oestradiol levels did not differ from placebo, and the effect on desire was independent of mood scores and hormone levels [23]. A companion report found no effect on any of the reproductive hormones measured [52].
In a randomized crossover pilot study in eight trained male cyclists, 14 days of maca extract improved self-rated sexual desire compared with placebo [25].
Women:
In a randomized, double-blind, placebo-controlled crossover trial, 14 postmenopausal women took 3.5 g a day of maca powder for 6 weeks. Sexual dysfunction scores fell compared with both baseline and placebo [26]. Estradiol, FSH, LH and sex hormone-binding globulin (SHBG) did not change.
A randomized, double-blind pilot study compared 1.5 g and 3.0 g of maca a day in 20 people with sexual dysfunction caused by SSRI antidepressants (17 were women). On 3.0 g a day, sexual dysfunction scores improved from baseline; on 1.5 g a day they did not [27]. The study compared two doses and had no placebo group.
Mechanism: Several trials found no change in sex hormone levels [23, 26, 52, 53]. Maca extracts showed no estrogenic or androgenic activity in yeast-based tests [26]. How maca works is still unclear [28]. Lab studies suggest macamides might act on the central nervous system by blocking FAAH [6].
Erectile Dysfunction
A double-blind trial randomized 50 men with mild erectile dysfunction to 2,400 mg of dry maca extract or placebo for 12 weeks [29]. Erectile function scores (IIEF-5) rose more on maca than on placebo (1.6 versus 0.5 points). Only the maca group improved on physical and social well-being scores compared with baseline. The authors described the effect as small but significant.
The 2010 systematic review counted this trial as positive but judged the overall evidence for sexual function too limited for firm conclusions [54].
Sperm Quality and Male Fertility
An early study gave nine men maca tablets (1500 or 3000 mg/day) for 4 months. Semen volume, sperm count per ejaculate, the number of motile sperm and sperm motility rose, while hormone levels did not change [32]. All nine men took maca; there was no comparison group.
A 2016 systematic review of five studies (three randomized trials and two uncontrolled studies) found suggestive evidence that maca improves semen quality, but too few, small and biased studies to draw firm conclusions [33]. A 2022 systematic review of five randomized trials found unclear effects on semen quality; its pooled analysis showed no clear rise in sperm concentration compared with placebo (weighted mean difference, 2.22, 95% confidence interval -2.94 to 7.37) [55].
In rats, black maca raised sperm counts within days of starting treatment [15].
Female Fertility
An extract of yellow maca increased litter size in female mice, and it increased uterine weight in mice whose ovaries had been removed [16]. This is a mouse study; it does not show that maca helps women conceive.
Menopausal Symptoms
Psychological symptoms: In the Brooks (2008) crossover trial, 14 postmenopausal women taking 3.5 g a day of maca powder for 6 weeks had lower psychological symptom scores, including anxiety and depression, than at baseline or on placebo, measured by the Greene Climacteric Scale [26]. Estradiol, FSH, LH and SHBG did not change. In a crossover trial in 29 postmenopausal Chinese women, 3.3 g a day for 6 weeks lowered depression scores, with no change in hormone levels [53].
Hot flashes and hormonal markers: In a crossover trial in 34 early-postmenopausal women, 2 g a day of pre-gelatinized maca (Maca-GO) for two months raised estradiol, lowered FSH and relieved menopausal symptoms, mainly hot flushes and night sweats [17]. A pilot trial by the same lead author in 20 perimenopausal women reported symptom relief in 74%-87% of women, with a clear placebo effect early in the study [34]. Unlike the other trials, these two reported changes in hormone levels.
Systematic review evidence: A 2011 systematic review found four randomized trials, all favoring maca, but judged the evidence limited because the trials were few, small and of limited quality; it added that maca's safety had not been proven [35].
Important distinction: Maca is not hormone therapy, and its trials have compared it only with placebo [35]. Do not use it in place of treatment your doctor recommends for severe menopausal symptoms.
Mood — Anxiety and Depression
Postmenopausal anxiety and depression: In the Brooks (2008) trial, anxiety and depression scores fell in 14 postmenopausal women taking 3.5 g a day of maca for 6 weeks, compared with placebo [26]. In the Hong Kong trial, depression scores also fell [53].
Reports of worse mental health: A review of online sources linked maca, among other sexual enhancement products, to mood changes, anxiety and hallucinations [61]. A 2024 report of two cases describes acute psychotic episodes after regular use of herbal products and discusses maca as a possible cause [60].
Synthesis: Small trials suggest maca may ease anxiety and depression symptoms in postmenopausal women [26, 53]. The trials were small and short, so maca cannot be recommended as a treatment for clinical anxiety or depression.
Physical Performance and Energy
Maca is marketed as "Peruvian Ginseng" [39].
Cycling performance: In eight trained male cyclists, 14 days of maca extract improved 40 km time trial performance compared with their baseline test, but not compared with placebo [25].
Systematic review evidence: A 2024 systematic review and meta-analysis of 21 studies in animals and humans found large effects on all its outcomes, including forced swimming, grip strength and lactic acid [56]. Its main outcomes included animal tests such as forced swimming, so the results say little about people.
Oxidative stress: A 2024 meta-analysis of eight studies found that maca lowered markers of oxidative stress, but noted that information in humans is scarce [57].
Osteoarthritis
Evidence for joint pain is limited.
A laboratory study found that a maca extract (RNI 249) raised production of IGF-1 (insulin-like growth factor 1) in human cartilage cells [40].
A randomized, double-blind trial in 95 adults with knee osteoarthritis compared reparagen (1800 mg/day), a combination of 300 mg of vincaria (Uncaria guianensis, a cat's claw species) and 1500 mg of the maca extract RNI 249 taken twice daily, with 1500 mg/day of glucosamine sulfate for 8 weeks. At least a 20% fall in pain scores occurred in 94% of people on reparagen and 89% on glucosamine, and the reparagen group used less rescue paracetamol [41].
Critical limitations: The trial compared reparagen with glucosamine and had no placebo group, and reparagen also contained cat's claw [41].
Prostate Health
Red maca reduced prostate size in normal rats and in rats given testosterone to enlarge the prostate [14]. This finding has been used to promote red maca for prostate health, but the evidence comes from rats.
Bone Density
In rats whose ovaries had been removed, a higher dose of maca extract prevented bone loss [21], and red maca reversed experimentally induced osteoporosis [9]. These are rat studies.
Neuroprotection and Cognition
In experimental studies, black maca gave the best results on memory [9]. Reviews list neuroprotection and memory among maca's possible effects, based on experimental work [30, 28].
Diabetes and Blood Sugar
A 2014 review reports that maca lowers glucose levels [9]. In a 6-week trial in 29 postmenopausal women, glucose did not change [53].
4. Recommended Dosing
Clinical Trial Doses
No official dosing guidelines exist for maca. Trials have used these doses:
| Indication | Dose | Form | Duration | Study |
|---|---|---|---|---|
| Sexual desire (men) | 1,500 mg or 3,000 mg/day | Gelatinized maca | 12 weeks | Gonzales 2002 [23] |
| Erectile dysfunction | 2,400 mg/day | Dry maca extract | 12 weeks | Zenico 2009 [29] |
| Menopausal symptoms (psychological) | 3.5 g/day | Maca powder | 6 weeks | Brooks 2008 [26] |
| Menopausal symptoms and blood pressure | 3.3 g/day | Maca | 6 weeks | Stojanovska 2015 [53] |
| Menopausal symptoms | 2 g/day | Pre-gelatinized maca | Two months | Meissner 2006 [17] |
| Sperm quality | 1500 or 3000 mg/day | Maca tablets | 4 months | Gonzales 2001 [32] |
General Recommendations
Typical dose range: Trials have used 1.5 g to 3.5 g a day [27, 26].
Form selection: Trials have used gelatinized maca, plain powder and extracts [23, 26, 29].
Timing: No specific timing relative to meals has been established. In two trials, capsules were taken twice daily with meals [17, 34].
Duration of use: Trials have lasted from 14 days [25] to 4 months [32].
Traditional Consumption
In the Andes maca is eaten as a food: cooked, baked, fermented into a drink or made into porridge [39]. Amounts eaten as food do not show what a safe supplement dose is.
5. Safety and Side Effects
General Safety Profile
In animals, maca has a low degree of acute oral toxicity, and it has low toxicity to cells in lab tests [4]. Experimental studies of short- and long-term use found no toxicity [9]. Human trials have been small and short, and a 2011 review noted that maca's safety had not been proven [35].
Reported Side Effects
- General tolerance: In a small trial in people taking SSRIs, side effects were common but mild and short-lived [27].
- Mild symptoms: In the SSRI trial, 11 of 16 people reported at least one side effect: stomach upset (5 people), headache (2), irritability (2), and one case each of panic attack, trouble sleeping, sweating and several other complaints. All were short-lived, and none led anyone to stop [27].
- Anxiety or mood changes: In the SSRI trial, one person had a panic attack and two had irritability, though the authors found it hard to link most events directly to maca [27]. Online reports link maca to mood changes, anxiety and hallucinations [61], and a 2024 report of two cases discusses maca as a possible cause of psychotic episodes [60].
Liver Enzyme Effects
In a 90-day randomized, placebo-controlled trial in people with the metabolic syndrome, maca at 0.6 g a day caused a moderate rise in the liver enzyme AST [42]. The authors advised that this be considered with high doses of maca powder. A 2017 case report describes liver injury in a man after one 300 ml drink of a maca medicinal liquor containing 50% alcohol; such liquors are made with traditional Chinese medicines, and its other ingredients were not listed [59]. LiverTox states that maca has not been implicated in liver injury, either as passing rises in liver enzymes or as clinically apparent liver injury [66]. In rat liver cells, maca extracts were not toxic [62]. People with liver disease should ask their doctor before taking maca.
Blood Pressure Effects
In the same trial, maca at 0.6 g a day raised diastolic blood pressure [42]. Other trials found the opposite: diastolic blood pressure fell in postmenopausal women [53], and blood pressure fell in perimenopausal women [34]. People with high blood pressure should check it when starting maca.
Thyroid Considerations
Maca contains glucosinolates [7], and some glucosinolates can affect the thyroid (they are goitrogenic) [51]. In one trial, thyroid-stimulating hormone (TSH) did not change [53]; in another, maca lowered the thyroid hormone T3 [17]. People with a thyroid condition (hypothyroidism, Hashimoto's thyroiditis, Graves' disease) should talk to their doctor before using maca.
MTCA Concerns
Maca contains a beta-carboline compound, (1R,3S)-1-methyltetrahydro-beta-carboline-3-carboxylic acid, which is reported to act on the central nervous system [7]. A toxicology review lists carbolines among maca's compounds of toxicological interest [4]. A French health agency issued an alert about powdered maca, describing an alkaloid derived from this compound that inhibits monoamine oxidase (MAO) [67]. The authors of a 2009 commentary reported that their lab found no effect on brain MAO [67], and later lab work found that maca root extracts did not inhibit MAO-A [68]. Its safety at supplement doses has not been well studied.
Hormone-Sensitive Conditions
Most human trials found no change in sex hormone levels [26, 52, 53]. Lab studies point the other way: maca extracts showed estrogenic activity in MCF-7 breast cancer cells [62], and maca increased uterine weight in mice without ovaries [16]. In triple-negative breast cancer cells, maca extract raised expression of MMP-1, a gene linked to cancer spread, and made the cells migrate more; the authors warned that eating maca may be dangerous [47]. People with a hormone-sensitive cancer (breast, uterine or ovarian) or condition (endometriosis, uterine fibroids) should talk to their doctor before using maca [47, 62].
Body Composition Claims
Claims that maca enlarges the breasts, hips or buttocks have not been tested in clinical trials.
Pregnancy and Lactation
No trial has tested maca in pregnancy or breastfeeding; the SSRI trial excluded women who were pregnant or breastfeeding [27]. Avoid it while pregnant or breastfeeding unless your doctor advises otherwise. A case report on lead in maca powder warns women of childbearing age to be aware that imported products may contain significant amounts of lead [58].
Psychiatric Effects
A 2024 report of two cases describes acute psychotic episodes after regular use of herbal products and discusses maca as a possible cause [60]. In the SSRI trial, one person had a panic attack, though the authors found it hard to link most side effects directly to maca [27]. People with bipolar disorder, a history of psychosis or another psychiatric condition should ask their doctor before using maca.
Long-Term Safety
Trials have lasted from 14 days to 4 months [25, 32]. A 2011 review said maca's safety had not been proven and called for larger studies [35].
Contaminant Concerns
Maca can contain lead. A woman aged 32 had a blood lead level of 44 μg/dL; after an earlier source was removed, her level rose again when she began taking maca root powder and fell when she stopped [58]. The authors warn that imported products may contain significant amounts of lead [58]. Mass production with fertilisers and pesticides may also affect product safety [39]. Choosing products tested by a third party for heavy metals is sensible; consumerlab.com and Labdoor publish testing results.
6. Drug Interactions
Few studies have tested maca with medicines.
Anticoagulant/Antiplatelet Medications
Maca has not been tested with warfarin or other blood thinners. If you take a blood thinner, check with your doctor or pharmacist before starting.
Hormone Therapies
Most human trials found no change in sex hormone levels, but lab studies found estrogen-like activity [26, 62]. Theoretical concerns apply to:
- Hormone replacement therapy (HRT): Maca may theoretically interact with estrogen or progesterone therapy, though no clinical interaction studies have been conducted
- Oral contraceptives: Theoretical concern based on estrogen-like activity in lab studies [62]
- Anti-estrogen medications (tamoxifen, aromatase inhibitors): Caution warranted given lab findings in breast cancer cells [47, 62]
Thyroid Medications
Because maca contains glucosinolates, some of which are goitrogenic [7, 51], it may in theory affect thyroid hormone replacement (levothyroxine) or anti-thyroid medicines. People taking thyroid medicines should talk to their doctor first.
Monoamine Oxidase Inhibitors (MAOIs)
Maca contains a beta-carboline compound reported to act on the central nervous system [7]. A French health agency alert said a related alkaloid inhibits MAO [67]. The authors of a 2009 commentary reported that their lab found no effect on brain MAO [67], and later lab work found no MAO-A inhibition by maca extracts [68]. Whether maca affects MAO inhibitor medicines (phenelzine, tranylcypromine, selegiline) is unknown. If you take prescription medicines, check with your doctor or pharmacist before starting.
SSRI Antidepressants
One small study tested maca in people taking SSRIs for sexual dysfunction [27]. Side effects were common but mild and short-lived [27]. A chart review of drug interactions reported restless legs syndrome with maca taken alongside the antidepressant mianserin [65]. People taking antidepressants should discuss maca with their prescriber.
Stimulant Medications
Maca has not been tested with methylphenidate or other ADHD stimulants. If you take prescription medicines, check with your doctor or pharmacist before starting.
Blood Pressure Medications
Diastolic blood pressure rose with maca in one trial [42] but fell in another [53]. People taking blood pressure medicines should check their blood pressure when adding maca.
Summary Table
| Drug Class | Concern | Recommendation |
|---|---|---|
| Anticoagulants (warfarin) | Not tested | Ask your doctor or pharmacist |
| Hormone therapies (HRT, OC, tamoxifen) | Estrogen-like activity in lab studies | Consult provider; avoid with hormone-sensitive cancers |
| Thyroid medications | Glucosinolate goitrogenic effects | Consult provider |
| MAO inhibitors | Contains a beta-carboline; a French alert cited MAO inhibition, later lab work found none [67, 68]; interaction unknown | Ask your doctor or pharmacist |
| SSRIs | One small trial; side effects common but mild and short-lived | Discuss with prescriber |
| Antihypertensives | Blood pressure rose in one trial and fell in others | Monitor blood pressure |
7. Dietary Sources
Maca is not commonly found in Western diets outside of supplement form. In the Andes, people eat it as a whole food.
Traditional Preparations
| Preparation | Description |
|---|---|
| Cooked maca | The root is cooked and eaten [39] |
| Baked maca | The root is baked [39] |
| Fermented drink | The root is fermented into a drink [39] |
| Porridge | The root is made into porridge [39] |
Nutritional Content of Dried Maca Root
Main constituents of dried maca root [3, 30]:
| Nutrient | Amount |
|---|---|
| Starch | Major constituent |
| Dietary fiber | Major constituent |
| Protein (essential amino acids) | Major constituent |
| Fatty acids | Present |
| Iron | Present |
| Calcium | Present |
| Copper | Present |
| Vitamin C | Present |
Modern Dietary Use
Outside the Andes, maca is sold as powder, capsules, pills, flour, liquor and extracts [28]. The powder is often stirred into drinks, smoothies or food.
Traditional Consumption Levels
Traditionally, maca is used as a tonic, a fertility enhancer for people and cattle, and a remedy for rheumatism, respiratory disorders and anaemia [39].
8. References
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[3] Wang S, Zhu F. "Chemical composition and health effects of maca (Lepidium meyenii)." Food Chem. 2019;288:422-443. doi: 10.1016/j.foodchem.2019.02.071. PMID: 30902313
[4] Valerio LG Jr, Gonzales GF. "Toxicological aspects of the South American herbs cat's claw (Uncaria tomentosa) and maca (Lepidium meyenii): a critical synopsis." Toxicol Rev. 2005;24(1):11-35. doi: 10.2165/00139709-200524010-00002. PMID: 16042502
[5] Wu H, Kelley CJ, Pino-Figueroa A, Vu HD, Maher TJ. "Macamides and their synthetic analogs: evaluation of in vitro FAAH inhibition." Bioorg Med Chem. 2013;21(17):5188-5197. doi: 10.1016/j.bmc.2013.06.034. PMID: 23891163
[6] Almukadi H, Wu H, Böhlke M, Böhlke C, Telange R, Ansari MS, Pino-Figueroa A. "The macamide N-3-methoxybenzyl-linoleamide is a time-dependent fatty acid amide hydrolase (FAAH) inhibitor." Mol Neurobiol. 2013;48(2):333-339. doi: 10.1007/s12035-013-8499-2. PMID: 23853040
[7] Piacente S, Carbone V, Plaza A, Zampelli A, Pizza C. "Investigation of the tuber constituents of maca (Lepidium meyenii Walp.)." J Agric Food Chem. 2002;50(20):5621-5625. doi: 10.1021/jf020280x. PMID: 12236688
[8] Esparza E, Hadzich A, Kofer W, Mithöfer A, Cosio EG. "Bioactive maca (Lepidium meyenii) alkamides are a result of traditional Andean postharvest drying practices." Phytochemistry. 2015;116:138-148. doi: 10.1016/j.phytochem.2015.02.030. PMID: 25817836
[9] Gonzales GF, Villaorduña L, Gasco M, Rubio J, Gonzales C. "Maca (Lepidium meyenii Walp), a review of its biological properties." Rev Peru Med Exp Salud Publica. 2014;31(1):100-110. PMID: 24718534
[14] Gonzales GF, Miranda S, Nieto J, Fernández G, Yucra S, Rubio J, Yi P, Gasco M. "Red maca (Lepidium meyenii) reduced prostate size in rats." Reprod Biol Endocrinol. 2005;3:5. doi: 10.1186/1477-7827-3-5. PMID: 15661081
[15] Gonzales GF, Nieto J, Rubio J, Gasco M. "Effect of black maca (Lepidium meyenii) on one spermatogenic cycle in rats." Andrologia. 2006;38(5):166-172. doi: 10.1111/j.1439-0272.2006.00733.x. PMID: 16961569
[16] Ruiz-Luna AC, Salazar S, Gonzales NJ, Rubio J, Gasco M, Gonzales GF. "Lepidium meyenii (maca) increases litter size in normal adult female mice." Reprod Biol Endocrinol. 2005;3:16. doi: 10.1186/1477-7827-3-16. PMID: 15869705
[17] Meissner HO, Mscisz A, Reich-Bilinska H, et al. "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." Int J Biomed Sci. 2006;2(4):375-394. PMID: 23675006
[21] Zhang Y, Yu L, Ao M, Jin W. "Effect of ethanol extract of Lepidium meyenii Walp. on osteoporosis in ovariectomized rat." J Ethnopharmacol. 2006;105(1-2):274-279. doi: 10.1016/j.jep.2005.12.013. PMID: 16466876
[23] Gonzales GF, Cordova A, Vega K, Chung A, Villena A, Góñez C, Castillo S. "Effect of Lepidium meyenii (maca) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men." Andrologia. 2002;34(6):367-372. doi: 10.1046/j.1439-0272.2002.00519.x. PMID: 12472620
[25] Stone M, Ibarra A, Roller M, Zangara A, Stevenson E. "A pilot investigation into the effect of maca supplementation on physical activity and sexual desire in sportsmen." J Ethnopharmacol. 2009;126(3):574-576. doi: 10.1016/j.jep.2009.09.012. PMID: 19781622
[26] Brooks NA, Wilcox G, Walker KZ, Ashton JF, Cox MB, Stojanovska L. "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." Menopause. 2008;15(6):1157-1162. doi: 10.1097/gme.0b013e3181732953. PMID: 18784609
[27] Dording CM, Fisher L, Papakostas G, Farabaugh A, Sonawalla S, Fava M, Mischoulon D. "A double-blind, randomized, pilot dose-finding study of maca root (L. meyenii) for the management of SSRI-induced sexual dysfunction." CNS Neurosci Ther. 2008;14(3):182-191. doi: 10.1111/j.1755-5949.2008.00052.x. PMID: 18801111
[28] Gonzales GF. "Lepidium meyenii (maca): a plant from the highlands of Peru, from tradition to science." Forsch Komplementmed. 2009;16(6):373-380. doi: 10.1159/000264618. PMID: 20090350
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