Maca Root: The Andean Secret That Fueled an Empire

The genome of maca doubled twice. Not once, the way many plants do over evolutionary time, but twice, approximately 6.7 million years ago, as the Andes were rising from 1,000 to 4,000 meters. The massive gene duplication that resulted gave the plant expanded stress-response pathways, cold tolerance, UV resistance, and a unique set of chemical compounds found in no other plant on earth.

That’s the short version of why maca exists. The longer version involves 2,000 years of human cultivation in a place where nothing else grows, colonial exploitation, near-extinction, scientific revival by a single Peruvian researcher, and, most recently, a biopiracy war between Peru and China.

The Only Crop at 4,500 Meters

Maca (Lepidium meyenii) is a cruciferous vegetable, a distant relative of broccoli and radish, that grows only in a narrow band of the Peruvian Andes between 3,800 and 4,500 meters elevation. The main growing region is the Meseta de Bombón, a high plateau surrounding Lake Chinchaycocha (Lake Junín) in the Junín province. Average annual temperature there hovers between 5 and 7 degrees Celsius. Nighttime temperatures drop to minus 10. The UV radiation is intense. The wind never stops.

No other food crop survives here. Maca does, and the genomic reason is now understood. A 2016 study by Zhang et al. in Molecular Plant sequenced maca’s genome and revealed it to be a disomic octoploid (2n = 8x = 64 chromosomes) with two species-specific whole-genome duplications. These duplications coincide with the rapid Andean uplift and directly expanded the gene families responsible for abiotic stress response and secondary metabolite production. Maca did not merely adapt to extreme altitude. Its genome restructured itself to make survival possible.

The plant looks like a turnip: a small rosette of leaves close to the ground protecting a bulbous root. Dried in the thin mountain air through traditional freeze-thaw cycles, the root can be stored for years.

What the Chroniclers Recorded

Archaeological evidence at Pachamachay cave in Junín, excavated by Ramiro Matos Mendieta in 1969-1970, suggests wild maca was consumed in the region as far back as 7,000 to 8,000 years ago. The domestication of maca, the deliberate cultivation of the plant, is more recent. Gustavo F. Gonzales of the Universidad Peruana Cayetano Heredia, who published the most comprehensive academic review of maca in 2012, estimates domestication at 1,300 to 2,000 years ago in the San Blas area of Junín by the Pumpush people.

The first written European reference to maca appears in Pedro Cieza de León’s Crónica del Perú (1553), where he described roots used for sustenance in the highlands of Bombón. A century later, Father Bernabé Cobo became the first writer to use the name “maca” in his Historia del Nuevo Mundo (completed 1653, published posthumously in the 1890s), describing it as growing in “the harshest and coldest areas of the province of Chinchaycocha where no other plant for man’s sustenance could be grown.” Cobo also referenced its aphrodisiac and fertility-enhancing properties.

The often-repeated story that Inca warriors consumed maca before battle and were then forbidden from eating it after conquering a city (to protect local women from their heightened desires) is harder to source. It traces not to a colonial chronicle but to Quiros and Aliaga Cardenas (1997), a modern secondary source. Whether they drew on a specific document or on oral tradition is unclear. The story may be accurate, but it should be taken as tradition, not documented history.

What is better documented is maca’s role as tribute. Colonial records from the Chinchaycocha region show that roughly 300 loads of half a bushel of maca, approximately 15,000 kilos, were collected annually. The Spanish continued demanding it as tribute after the conquest, and notably, they also fed it to their livestock. Horses, pigs, and chickens thrived on it in the highlands.

The Chemistry Nobody Expected

The most scientifically interesting thing about maca is not its nutritional content (though it is genuinely nutritious: 60-75% carbohydrates, 10-14% protein with all essential amino acids, rich in iron, copper, zinc, and manganese). It’s a class of compounds called macamides: fatty acid derivatives that exist in no other known plant.

Macamides were first identified around 2000 by Zheng et al. in the journal Urology. By 2013, about 19 had been characterized; more recent work has expanded the count to over 50. They are secondary amides of long-chain fatty acids with benzylamine, and their biological activity is increasingly well understood: they function as fatty acid amide hydrolase (FAAH) inhibitors.

FAAH is the enzyme that breaks down anandamide, the body’s endogenous cannabinoid. By slowing FAAH activity, macamides potentially increase anandamide levels in the body, which could explain effects on mood, pain perception, and sexual desire. Wu et al. (2013) and Alasmari et al. (2018) demonstrated this mechanism in vitro: macamides containing oleic, linoleic, and linolenic acids produced FAAH inhibition of 64%, 73%, and 54% respectively. This is a plausible mechanism for some of maca’s traditional uses, though it has not been confirmed in human studies.

Here is where it gets truly interesting. A 2015 study found that macamides are not present in fresh maca roots. They are created during the traditional Andean post-harvest drying process, where freeze-thaw cycles trigger enzymatic reactions that combine benzylamine (from glucosinolate breakdown) with fatty acids to form the macamides. The Andean farmers who have dried maca in mountain air for centuries were, without knowing the chemistry, manufacturing the bioactive compounds through their processing method. The modern practice of eating “raw” maca powder has no traditional precedent and produces a nutritionally different product.

Maca’s glucosinolate profile is also unusual. It contains about 1% glucosinolates by weight, roughly 100 times more than typical cruciferous vegetables. But the type matters: around 80% of maca’s glucosinolates are benzyl glucosinolate (aromatic type), not the indole or aliphatic glucosinolates found in broccoli and cabbage. This means that sulforaphane, the much-studied compound in broccoli, is not present in maca in meaningful amounts. Maca’s glucosinolate metabolites are different compounds with different biological activities.

What the Studies Actually Show

Let’s be direct about the state of maca research. Most clinical trials are small, short, and come from a limited number of research groups. That said, a pattern has emerged.

Sexual function: The strongest human evidence is for improved sexual desire. Gonzales et al. (2002) conducted a 12-week double-blind, placebo-controlled trial with 56 men and found self-reported sexual desire improved from week 8 onward. Crucially, serum testosterone, estradiol, LH, FSH, and prolactin were unchanged. Whatever maca does for libido, it does not appear to work through sex hormones in men. The most recent and largest study, Shin et al. (2023), confirmed this pattern in 80 Korean men with late-onset hypogonadism: sexual function scores improved, testosterone levels did not budge.

Fertility: The sperm-parameter claims rest on shakier ground. The foundational study (Gonzales et al. 2001) had only 9 participants and no placebo control. Animal studies, particularly from Gonzales’s group, suggest black maca specifically may affect sperm production, but no human trial has compared maca color varieties directly.

Menopause: Several small studies show reduced anxiety, improved mood, and decreased menopausal discomfort. Results are mixed on whether maca affects hormone levels in women. Brooks et al. (2008) found improvements in 14 postmenopausal women with no hormonal changes. A pilot sub-study by Meissner et al. (2005) found that in a small cohort of 8 women followed for 8 months, FSH decreased and estradiol increased. The discrepancy may reflect differences in study duration or maca preparation.

Athletic performance: One often-cited study (Stone et al. 2009) found that 8 cyclists improved their time trial performance, but the improvement was not statistically significant compared to placebo. The honest reading: maca does not have strong evidence as a sports performance enhancer.

Cognitive function: All evidence is from animal models. No human clinical trial has been published on maca and cognitive function. The claims that maca improves memory or focus in humans are currently unsupported by direct evidence.

The color-variety claims (black maca for fertility, red for prostate health) come from a small body of animal studies, primarily from one research group. The 2024 review in Nutrients (“Not All Maca Is Created Equal”) confirmed real phytochemical differences between colors but noted the near-total absence of comparative human trials.

Near-Extinction and the Biopiracy War

By the 1980s, maca cultivation had nearly disappeared. Migration to cities, competition from introduced crops, and loss of traditional knowledge reduced the total cultivated area to somewhere between 15 and 50 hectares in all of Peru (Tello et al. 1992). By 1982, maca was declared in danger of extinction as a domesticated plant, a status later highlighted in the National Research Council’s 1989 report Lost Crops of the Incas.

The revival began with one researcher: Gloria Chacón de Popovici. Her 1961 bachelor’s thesis at the National University of San Marcos was the first modern scientific study of maca. She spent decades researching its phytochemistry and eventually argued that the cultivated plant was sufficiently different from the wild specimen to deserve its own species name, Lepidium peruvianum Chacón. (The international botanical community has not accepted this reclassification; most databases still use L. meyenii, the name Gerhard Walpers assigned in 1843 based on a specimen from Pisacoma in the Department of Puno.) Her work, combined with growing international interest in the 1990s, sparked a revival. By 1999, cultivation had expanded to over 1,200 hectares.

Then came China.

In 2003, Peru made it illegal to export whole maca roots or seeds, specifically to prevent biopiracy. Despite this, beginning around 2013, Chinese businessmen arrived in Junín and began smuggling maca bulbs out through the Bolivian border and the port of Callao. Between 2013 and 2014, Chinese demand for maca increased roughly tenfold. By 2014, China had an estimated 12,000 hectares of maca under cultivation, primarily in Yunnan Province, with expansion into Tibet, Qinghai, and Xinjiang. Peru had only about 5,000 hectares. The tonka bean’s story of colonial extraction follows a similar pattern, but maca’s case is more extreme: over 1,700 patent applications related to maca have been filed worldwide, and 75% come from China.

The economic impact was devastating. Peruvian maca exports crashed from approximately US$5 million in 2014 to near zero as Chinese-grown maca undercut prices. Growers stockpiled tons of dried roots they couldn’t sell. A plant that had been cultivated exclusively in a 50-kilometer radius for two thousand years was now being mass-produced on another continent.

How to Use It

Traditional Andean preparation always involved drying and then cooking. Maca was never eaten raw. The most common methods were mazamorra (a porridge made by boiling dried roots until soft), huatia (cooking in earthen ovens), and chicha de maca (a fermented drink). These methods all apply heat, which breaks down starches, reduces goitrogenic activity, and produces an easily digestible food.

Modern forms include:

Gelatinized powder (heat-treated to break down starches, no actual gelatin): easier to digest, more concentrated, lower goitrogen activity. Best for beginners and sensitive stomachs.

Raw powder (dried and ground without heat): earthier flavor, may cause digestive discomfort. Notably, this has no traditional precedent, and the macamide content may differ from traditionally processed maca.

Starting dose: 1-3 grams per day (roughly half to one teaspoon of powder), preferably with food in the morning. Traditional use involved much higher quantities, up to 9 grams daily, but as whole food, not concentrated supplements.

Thyroid note: If you have thyroid concerns, choose gelatinized maca. Heat denatures myrosinase, the enzyme that converts glucosinolates to goitrogenic isothiocyanates. Ensure adequate iodine intake and consult your healthcare provider.

Two Readings

The skeptical reading is straightforward. Maca is a starchy root vegetable that happens to grow at high altitude and contains some unusual secondary metabolites. Its traditional reputation for enhancing vitality and sexual function has been partially supported by small clinical trials, but the effect sizes are modest, the sample sizes are tiny, and the strongest evidence (FAAH inhibition) remains limited to in-vitro studies. The warrior stories are modern retellings without primary sources. The revival was driven by commercial interest as much as by science. And as ginseng demonstrates, plants with traditional “vitality” reputations tend to accumulate medical claims far beyond what controlled evidence supports.

The other reading notices something harder to dismiss. A plant whose genome restructured itself twice to survive at an altitude that kills all other food crops. Unique compounds that exist nowhere else in the plant kingdom and that happen to interact with the endocannabinoid system. A traditional processing method that, without any knowledge of organic chemistry, creates the very bioactive molecules that modern researchers have only recently identified. Two thousand years of continuous use by peoples who valued the root enough to accept it as payment for imperial taxes. And a body of clinical research that, however small, consistently points in the same direction: something is happening, even if we cannot yet fully explain what.

The macamides are real. The FAAH inhibition is real. The clinical improvements in sexual function are real, if modest. The genome duplication is real. The 2,000-year chain of cultivation, from the Pumpush people of the Junín plateau through the Inca empire through colonial extraction through near-extinction through revival through biopiracy, is real. Whether what modern science has captured in small trials accounts for what Andean peoples have known about this root for millennia, or whether there are mechanisms we have not yet identified, is a question the evidence raises but does not resolve.