Lepidium meyenii is the scientific name for maca, a root vegetable native to the high-altitude plateaus of the Peruvian Andes. It belongs to the Brassicaceae (mustard) family, making it a relative of broccoli, cauliflower, and radishes. Cultivated for more than 2,000 years, maca has been used as both a staple food and a traditional remedy, and it has gained worldwide popularity as a supplement marketed for energy, hormonal balance, and sexual health.
Where Maca Grows and Why It Matters
Maca grows exclusively in the central Andes at elevations between 4,000 and 4,500 meters (roughly 13,000 to 14,800 feet), in areas marked by intense cold, powerful UV radiation, and relentless winds. The primary growing region sits on the Junín Plateau near Cerro de Pasco in Peru, encompassing the towns of Carhuamayo, Junín, and Óndores. Few food crops survive at this altitude, which makes maca nutritionally significant to the communities that cultivate it.
The plant has adapted to these extreme conditions in visible ways. Its above-ground portion stays small and flat against the soil, reducing wind exposure. The edible part is the hypocotyl, a bulbous, turnip-like root that grows underground and stores the plant’s energy and nutrients. Maca roots come in several colors, including yellow, red, and black, and each variety has a slightly different phytochemical profile.
Nutritional Profile
As a root vegetable, maca is high in starch and provides a meaningful amount of protein, fiber, and several minerals. Dried maca powder contains iron, copper, potassium, and calcium, along with B vitamins. It also contains compounds called glucosinolates, which are common across the mustard family and contribute to its slightly peppery, earthy flavor.
Beyond basic nutrition, maca contains bioactive compounds that set it apart from other root vegetables. These include macamides and macaenes, two classes of fatty acid derivatives found almost exclusively in this plant. Researchers believe these compounds, along with alkaloids unique to maca, are responsible for many of its reported biological effects, though the exact mechanisms remain under investigation.
How Maca Affects Hormones
One of the most common claims about maca is that it balances hormones. Early research proposed that maca alkaloids act on the hypothalamus-pituitary-adrenal (HPA) axis, the signaling chain your brain uses to regulate stress hormones, reproductive hormones, and metabolism. However, this hypothesis has not been confirmed. More recent evidence suggests maca’s effects on this hormonal pathway likely involve a synergy between multiple compounds rather than a single active ingredient.
Importantly, clinical studies have generally found that maca does not directly raise or lower levels of hormones like testosterone or estrogen in the blood. This distinguishes it from hormone replacement therapy or phytoestrogens. Whatever benefits people experience may come from how the body responds to maca’s compounds at a cellular level rather than from changes in circulating hormone concentrations.
Mood, Anxiety, and Depression
Some of the strongest clinical evidence for maca involves mood. In a study of postmenopausal women, maca supplementation was associated with a roughly 31% reduction in anxiety scores and a 29% reduction in depression scores compared to baseline, both statistically significant. The women’s health questionnaire used in the same trial confirmed improvements in both anxiety and depression symptoms. Separate analyses using the Greene Climacteric Scale, a standard tool for measuring menopausal symptoms, also showed lower scores in psychological symptom categories after maca use.
A study in Chinese postmenopausal women found similar patterns: significant improvement in depression scores and anxiety scores, along with improved general and mental health ratings. The reductions ranged from 27% to 36% depending on the specific measure. It is worth noting that in some of these trials, the placebo group also showed improvement, which is common in mood research. Still, the differences between maca and placebo remained statistically significant.
Menopausal Symptoms
Beyond mood, maca has been studied specifically for the broader constellation of menopausal symptoms, including hot flashes, night sweats, and sleep disruption. A systematic review of randomized controlled trials found that all included studies demonstrated favorable effects of maca, as measured by both the Kupperman Menopausal Index and the Greene Climacteric Score. These are two of the most widely used tools for quantifying menopause symptom severity, and improvements on both suggest a broad rather than narrow benefit.
Because maca does not appear to raise estrogen levels significantly, it may appeal to women who want to manage menopausal discomfort without hormonal interventions. That said, the total number of clinical trials remains relatively small, and most have used modest sample sizes.
Sexual Health and Fertility
Maca’s traditional reputation centers heavily on sexual vitality, and this remains one of the primary reasons people seek it out. Several small clinical trials have reported improvements in self-reported sexual desire in both men and women after several weeks of supplementation. These findings are consistent, but the trials tend to be small and short in duration.
Some animal and preliminary human studies have also examined maca’s effects on sperm quality, including sperm count and motility. While results have been promising in early research, the evidence is not yet robust enough to draw firm conclusions about fertility outcomes in humans.
Physical Performance and Energy
Maca is frequently marketed as an energy booster, and there is some clinical data to support modest effects on physical performance. In one study, trained cyclists who took maca improved their 40-kilometer time trial from an average of 57.62 minutes to 56.56 minutes, a statistically significant improvement of about one minute. That is a meaningful gain for endurance athletes, though it came from a single study.
Other trials have been less clear-cut. One study measuring time to exhaustion during exercise found no significant difference between the maca group and the control group. Similarly, a study measuring subjective energy levels on a visual scale found that while participants in the maca group reported feeling less fatigued after supplementation, the difference compared to the control group was not statistically significant. The current evidence suggests maca may offer a small endurance benefit, but it is unlikely to produce dramatic changes in energy or athletic performance.
Raw vs. Gelatinized Maca
Maca supplements come in two main forms: raw powder and gelatinized powder. The term “gelatinized” is misleading because it has nothing to do with gelatin. It refers to an extrusion process that uses high pressure, heat, and moisture to break down the root’s starch content. The result is a powder that is easier to digest and may have more bioavailable active compounds.
Gelatinized maca can be a better choice for people with sensitive digestion or those following a low-FODMAP diet. The process also appears to reduce the content of goitrogens, compounds found across the mustard family that can interfere with thyroid hormone activity. Raw maca retains these goitrogens at higher levels, which is a consideration for anyone with an existing thyroid condition. If thyroid health is a concern, the gelatinized form carries a lower risk of interference.
Typical Doses Used in Research
Most clinical studies have used doses ranging from 1.5 to 3 grams of dried maca powder per day, taken for periods of 6 to 12 weeks. In traditional Peruvian use, people consume considerably more, sometimes 20 grams or more daily as a food, typically after boiling or roasting the root. Maca has a strong safety record at the doses used in research, with no serious adverse effects reported in published trials. Digestive discomfort is the most commonly noted side effect, particularly with raw (non-gelatinized) forms.