Maca

Maca was probably domesticated at San Blas (today Ondores) on the Junín plateau, some 1,300–2,000 years ago ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}. In 1553 the Spanish chronicler Cieza de León noted that the people of the province of Bombón (today Junín) lived on certain roots; these were maca. Father Cobo was the first to record the name maca and describe its properties, in 1653 ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

It is used traditionally as a tonic and as a fertility enhancer for both people and cattle, and for rheumatism, respiratory complaints and anaemia ^{28Reference 28Beharry et al. · 2018ReviewIs the hype around the reproductive health claims of maca (Lepidium meyenii Walp.) justified? — reviewView study →}. It is also taken as an energizer ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

Peruvian folk medicine uses it as an immune stimulant and for anaemia, tuberculosis, menstrual disorders, menopausal symptoms, stomach cancer, sterility and other reproductive and sexual complaints, and to improve memory ^{35Reference 35FernFern, K. (n.d.). Lepidium meyenii — plant description, native range, cultivation conditions and uses — plant database. Useful Tropical Plants (Tropical Plants Database). https://tropical.theferns.info/viewtropical.php?id=Lepidium+meyeniiView study →}.

Andean people traditionally distinguish maca by the colour of the root ^{17,23Reference 17Rubio et al. · 2006AnimalEffect of three different cultivars of Lepidium meyenii (Maca) on learning and depression in ovariectomised mice — animal modelView study →Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}. They boil it before eating, and advise against eating it fresh ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

In a survey at Carhuamayo (4,100 m), people who ate maca had better health scores, fewer fractures and fewer signs of chronic mountain sickness than those who did not ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

In a 12-week double-blind, placebo-controlled trial in men aged 21–56, gelatinized maca at 1,500 or 3,000 mg/day improved self-reported sexual desire from week 8. Regression analysis showed the effect was independent of depression and anxiety scores and of serum testosterone and estradiol, which did not change ^{1Reference 1Gonzales et al. · 2002RCTEffect of Lepidium meyenii (Maca) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men — randomised placebo-controlled trialView study →}.

In a 14-day crossover trial in eight trained male cyclists, maca extract raised self-rated sexual desire compared with both baseline and placebo ^{3Reference 3Stone et al. · 2009RCTA pilot investigation into the effect of maca supplementation on physical activity and sexual desire in sportsmen — randomised crossover trialView study →}.

A 2010 systematic review of four RCTs found positive effects on sexual desire or dysfunction in healthy men, in menopausal women and in men with erectile dysfunction, but judged the cyclist trial negative. It rated the overall evidence as limited ^{2Reference 2Shin et al. · 2010Systematic reviewMaca (L. meyenii) for improving sexual function: a systematic reviewView study →}.

Gap: Every positive result relies on self-report questionnaires, and the samples are small.

In a 12-week double-blind RCT in 50 men with mild erectile dysfunction, maca dry extract 2,400 mg/day raised IIEF-5 scores by 1.6 points, against 0.5 with placebo. It also improved physical and social well-being scores ^{4Reference 4Zenico et al. · 2009RCTSubjective effects of Lepidium meyenii (Maca) extract on well-being and sexual performance in patients with mild erectile dysfunction — randomised double-blind clinical trialView study →}.

A 2023 RCT in 80 men with normal testosterone but symptoms of late-onset hypogonadism found that gelatinized maca, 6 g/day for 12 weeks, improved erectile function (IIEF), ageing-male symptoms and prostate-symptom scores more than placebo ^{5Reference 5Shin et al. · 2023RCTEfficacy and safety of Maca (Lepidium meyenii) in patients with symptoms of late-onset hypogonadism — randomised placebo-controlled trialView study →}.

A 2025 meta-analysis of 14 RCTs of herbal supplements for erectile dysfunction (1,227 men) found a positive pooled effect for the class, with the clearest support for saffron and ginseng. It judged the evidence for maca insufficient ^{6Reference 6Ho et al. · 2025Meta-analysisHerbal dietary supplements for erectile dysfunction: a systematic review and meta-analysis of randomised controlled trialsView study →}.

A review author reported an unpublished 12-week trial of gelatinized maca that found no effect on erection in healthy men ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

Gap: No large, maca-only, placebo-controlled trial with objective erectile endpoints.

Two double-blind trials from the same group tested maca for the sexual side effects of SSRI and SNRI antidepressants. In a dose-finding pilot in 20 people whose depression had remitted, 3.0 g/day significantly improved ASEX and MGH-SFQ sexual-function scores, while 1.5 g/day did not ^{7Reference 7Dording et al. · 2008RCTA double-blind, randomised, pilot dose-finding study of maca root (L. meyenii) for the management of SSRI-induced sexual dysfunctionView study →}.

In a 12-week placebo-controlled trial in 45 women, remission rates were higher on 3.0 g/day than on placebo (for example, 30% versus 20% on one MGH-SFQ threshold). The benefit was linked to postmenopausal status ^{8Reference 8Dording et al. · 2015RCTA double-blind placebo-controlled trial of maca root as treatment for antidepressant-induced sexual dysfunction in women — randomised controlled trialView study →}.

Gap: Small samples from a single research group, with modest absolute remission rates.

In an open study in nine healthy men, maca tablets (1,500 or 3,000 mg/day for four months) increased seminal volume, sperm count and motility, without changing LH, FSH, prolactin, testosterone or estradiol ^{10Reference 10Gonzales et al. · 2001Lepidium meyenii (Maca) improved semen parameters in adult menView study →}.

A 2020 double-blind RCT in 69 men with mildly low sperm count or motility found that maca 2 g/day for 12 weeks increased sperm concentration versus placebo (15.0 versus 10.2 million/mL). Semen volume, motility and morphology did not differ ^{9Reference 9Alcalde et al. · 2020RCTDoes Lepidium meyenii (Maca) improve seminal quality? — randomised double-blind placebo-controlled trialView study →}.

A 2016 systematic review of five studies (three RCTs and two uncontrolled) judged the evidence suggestive of benefit, but too limited for firm conclusions ^{11Reference 11Lee et al. · 2016Systematic reviewThe use of maca (Lepidium meyenii) to improve semen quality: a systematic reviewView study →}.

In rats, maca increased sperm count in a dose-dependent way and prevented the loss of sperm production caused by high altitude (4,340 m) ^{12Reference 12Gonzales et al. · 2004AnimalEffect of Lepidium meyenii (Maca) on spermatogenesis in male rats acutely exposed to high altitude — animal modelView study →}. Black maca, and to a lesser degree yellow maca, raised sperm count and motility in rats, while red maca had no effect ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

Gap: Human trials are small and short, and only sperm concentration has replicated.

A 2011 systematic review found four RCTs, all reporting favourable effects on menopausal symptom scores (Kupperman Index, Greene Climacteric Scale). It judged the evidence limited and noted that safety had not been established ^{13Reference 13Lee et al. · 2011Systematic reviewMaca (Lepidium meyenii) for treatment of menopausal symptoms: a systematic reviewView study →}.

In a crossover RCT in 14 postmenopausal women, powdered maca 3.5 g/day for six weeks lowered Greene Climacteric scores for psychological symptoms and sexual dysfunction, with no change in estradiol, FSH, LH or SHBG. Maca extracts showed no oestrogenic or androgenic activity in yeast-based assays ^{14Reference 14Brooks et al. · 2008RCTBeneficial effects of Lepidium meyenii (Maca) on psychological symptoms and measures of sexual dysfunction in postmenopausal women are not related to oestrogen or androgen content — randomised controlled trialView study →}.

A 2018 meta-analysis of phytoestrogens found that maca improved sexual function in menopausal women ^{16Reference 16Najaf Najafi et al. · 2018Meta-analysisEffect of phytoestrogens on sexual function in menopausal women: a systematic review and meta-analysisView study →}.

In ovariectomized rats, 28 weeks of an ethanolic maca extract prevented the rise in FSH ^{24Reference 24Zhang et al. · 2014AnimalEffect of ethanolic extract of Lepidium meyenii Walp on serum hormone levels in ovariectomised rats — animal modelView study →}, and a gelatinized maca preparation had antidepressant-like effects ^{25Reference 25Meissner et al. · 2006AnimalHormone-balancing effect of pre-gelatinised organic maca (Lepidium peruvianum Chacon): biochemical and pharmacodynamic study on ovariectomised rats — animal modelView study →}.

Gap: Trials are small and differ in preparation and dose, and long-term safety in this group has not been established.

In the 14-woman postmenopausal crossover RCT, maca reduced anxiety and depression scores on the Greene scale compared with baseline and placebo ^{14Reference 14Brooks et al. · 2008RCTBeneficial effects of Lepidium meyenii (Maca) on psychological symptoms and measures of sexual dysfunction in postmenopausal women are not related to oestrogen or androgen content — randomised controlled trialView study →}.

A crossover RCT in 29 postmenopausal women in Hong Kong found that maca 3.3 g/day for six weeks lowered depression scores and diastolic blood pressure, with no change in hormones, lipids, glucose or cytokines ^{15Reference 15Stojanovska et al. · 2015RCTMaca reduces blood pressure and depression in a pilot study in postmenopausal women — randomised controlled trialView study →}.

In ovariectomized mice, yellow, red and black maca all reduced immobility in the forced-swim test, an antidepressant-like effect ^{17Reference 17Rubio et al. · 2006AnimalEffect of three different cultivars of Lepidium meyenii (Maca) on learning and depression in ovariectomised mice — animal modelView study →}.

The human data are limited to postmenopausal women, with mood measured as a secondary outcome.

In hypertriglyceridemic rats, 1% dietary maca for two weeks raised liver SOD and glutathione and blood glutathione peroxidase, and lowered blood lipids and glucose ^{22Reference 22Vecera et al. · 2007AnimalThe influence of maca (Lepidium meyenii) on antioxidant status, lipid and glucose metabolism in rats — animal modelView study →}.

In ovariectomized mice, black maca lowered brain malondialdehyde, a marker of lipid peroxidation ^{18Reference 18Rubio et al. · 2011AnimalAqueous extract of black maca (Lepidium meyenii) on memory impairment induced by ovariectomy in mice — animal modelView study →}.

No human study has measured an oxidative-stress marker after maca.

Aqueous black-maca extract (0.5 and 2.0 g/kg for 35 days) improved learning and memory in ovariectomized mice, while lowering brain malondialdehyde and acetylcholinesterase (AChE) activity ^{18Reference 18Rubio et al. · 2011AnimalAqueous extract of black maca (Lepidium meyenii) on memory impairment induced by ovariectomy in mice — animal modelView study →}. Aqueous and hydroalcoholic black-maca extracts also corrected scopolamine-induced memory loss in male mice, again with AChE inhibition ^{19Reference 19Rubio et al. · 2007AnimalAqueous and hydroalcoholic extracts of black maca (Lepidium meyenii) improve scopolamine-induced memory impairment in mice — animal modelView study →}.

In ovariectomized mice, black maca gave the best result of the three colours in a learning task ^{17Reference 17Rubio et al. · 2006AnimalEffect of three different cultivars of Lepidium meyenii (Maca) on learning and depression in ovariectomised mice — animal modelView study →}.

Gap: No human cognition trials; the data come from rodent models with black maca.

In rats with prostate enlargement induced by testosterone enanthate, aqueous and hydroalcoholic extracts of red maca reduced prostate weight. The effect increased with the extracts’ content of benzyl glucosinolate ^{20Reference 20Gonzales et al. · 2007AnimalEffect of two different extracts of red maca in male rats with testosterone-induced prostatic hyperplasia — animal modelView study →}.

A freeze-dried aqueous red-maca extract (0.01–0.5 g/kg) reduced prostate weight in a dose-dependent way, more than finasteride. Unlike finasteride, it did not reduce seminal-vesicle weight, and serum testosterone was unchanged. The extract contained 0.639% benzyl glucosinolate (glucotropaeolin) ^{21Reference 21Gasco et al. · 2007AnimalDose-response effect of red maca (Lepidium meyenii) on benign prostatic hyperplasia induced by testosterone enanthate — animal modelView study →}.

Gap: No human BPH trial exists.

In a crossover RCT, eight trained cyclists taking maca extract for 14 days improved their 40 km time-trial time compared with their own baseline, but not compared with placebo ^{3Reference 3Stone et al. · 2009RCTA pilot investigation into the effect of maca supplementation on physical activity and sexual desire in sportsmen — randomised crossover trialView study →}.

A 2024 systematic review and meta-analysis reported large effects on physical performance. Its main outcomes were animal tests such as forced swimming, the rota-rod and grip strength ^{29Reference 29Huerta Ojeda et al. · 2024Meta-analysisEffects of maca (Lepidium meyenii Walp.) on physical performance in animals and humans: a systematic review and meta-analysisView study →}.

Gap: The one placebo-controlled human trial found no difference from placebo.

Maca inhibits angiotensin-converting enzyme (ACE) in vitro and is rich in potassium ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}. In the 29-woman postmenopausal RCT, maca lowered diastolic blood pressure ^{15Reference 15Stojanovska et al. · 2015RCTMaca reduces blood pressure and depression in a pilot study in postmenopausal women — randomised controlled trialView study →}. In a Peruvian community that traditionally eats maca, systolic blood pressure was lower than in those who did not ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

In a 90-day trial in people with metabolic syndrome, the group taking maca with silymarin had a moderate rise in diastolic blood pressure and the liver enzyme AST ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

Gap: No dedicated blood-pressure trial exists.

Red and black maca extracts protected bone structure in ovariectomized rats without oestrogen-like effects ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

In a seven-week study in ovariectomized rats, high-dose maca kept alkaline phosphatase, triglycerides and LDL cholesterol near normal; the model itself did not reduce femoral bone density ^{26Reference 26Wang et al. · 2009AnimalInfluence of Lepidium meyenii Walp on lipid and bone mass in ovariectomised rats — animal modelView study →}.

In a Peruvian community, people who ate maca reported fewer fractures than those who did not ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}. There are no human trials for bone.

Food use. People in the central Andes eat more than 20 g of maca a day, and no adverse reactions to maca as food have been reported ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}. A survey in Carhuamayo (4,100 m) found normal liver and kidney function, lipids and blood sugar in people who eat maca ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}. Local people boil maca before eating it, because fresh maca is thought to be harmful; this has not been studied ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

Trials. Human trials report maca as well tolerated, with rare, mild side effects ^{7,8Reference 7Dording et al. · 2008RCTA double-blind, randomised, pilot dose-finding study of maca root (L. meyenii) for the management of SSRI-induced sexual dysfunctionView study →Reference 8Dording et al. · 2015RCTA double-blind placebo-controlled trial of maca root as treatment for antidepressant-induced sexual dysfunction in women — randomised controlled trialView study →}.

Animal toxicity. Black, red and yellow maca showed no acute toxicity in rats at up to 17 g of dried root per kg. Rats given 1 g/kg for 84 days showed no side effects and normal liver tissue. Maca extracts were not toxic to liver cells in vitro, and did not harm the development of early mouse embryos ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

MTCA. Maca contains MTCA, a β-carboline that prompted a French food-safety opinion. MTCA also occurs in oranges, grapefruit and fermented garlic, sometimes at higher levels than in maca ^{23Reference 23Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}.

Mustard family. Maca is a Brassicaceae root containing glucosinolates, so people with an allergy to cabbage-family plants should take care.

Interactions. Drug interactions have not been studied. Because maca does not alter sex-hormone levels in trials, its interaction with hormone therapy is unknown ^{1,14Reference 1Gonzales et al. · 2002RCTEffect of Lepidium meyenii (Maca) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men — randomised placebo-controlled trialView study →Reference 14Brooks et al. · 2008RCTBeneficial effects of Lepidium meyenii (Maca) on psychological symptoms and measures of sexual dysfunction in postmenopausal women are not related to oestrogen or androgen content — randomised controlled trialView study →}.