What is Maca?
Maca (Lepidium meyenii) is a root vegetable native to the Peruvian highlands, typically grown at 3,500–4,300 meters elevation. Also known as “Peruvian ginseng,” it has been part of traditional Andean diets and folk medicine for centuries, with historical records suggesting use dating back to pre-Columbian times. The dried root powder is now widely sold in Western markets as a dietary supplement, often promoted for sexual function, energy, mood, and hormonal balance.
Traditional Use and Chemistry
Maca contains a variety of phytochemicals including glucosinolates, macamides, and other alkaloids that have generated interest in the scientific community. Proponents suggest these compounds may influence dopamine, serotonin, or hormone-related pathways. However, the exact mechanism by which maca might affect sexual function or well-being remains unclear, as high-quality mechanistic studies are lacking.
Evidence for Sexual Function
The strongest evidence for maca relates to sexual desire and erectile function, primarily in small human trials. A 2002 study by Gonzales and colleagues found that men taking maca showed improvements in sexual desire compared to placebo, without measurable changes in testosterone or other major hormones—an unexpected finding that suggests effects may be psychological or depend on downstream mechanisms not captured by basic hormone assays. More recent systematic reviews note these improvements consistently, but also acknowledge that most trials are small (typically 20–60 participants), short in duration (8–12 weeks), and sometimes poorly designed by modern standards.
Evidence is less clear for women. Some studies report benefits for sexual function or satisfaction in menopausal or postmenopausal women, but the number of high-quality trials remains limited.
Menopausal Symptoms and Mood
A 2008 study by Brooks and colleagues examined maca in menopausal women and found modest improvements in self-reported well-being and mood, though the sample was small and the clinical significance uncertain. Sexual dysfunction associated with menopause showed some improvement in certain trials, though effect sizes were generally small. Whether these benefits persist beyond the trial period or scale to broader quality-of-life improvements remains unknown.
Hormone and Fertility Effects
Claims that maca improves testosterone, estrogen balance, or fertility are popular in online marketing. However, the human evidence is mixed. While a few small studies suggest possible benefits for sperm count or motility in men, the effect sizes are modest and not consistently replicated. For women, evidence for fertility benefit is anecdotal rather than rigorously demonstrated. Maca does not appear to significantly alter major circulating hormones in most users, which both explains its likely safety profile and raises questions about mechanisms behind reported benefits.
Safety and Tolerability
Maca appears well-tolerated in short-term use, with most adverse events in trials being mild gastrointestinal symptoms or headache. No serious safety signals have emerged from the available literature. Long-term safety data (beyond 12–24 weeks) are sparse. Because maca does not exert strong hormonal effects in most users, concerns about hormone-sensitive cancers or estrogen dominance are largely theoretical. However, individuals on blood thinners or with thyroid disease should exercise caution, as some traditional uses and preliminary in vitro data have raised questions (though human evidence of clinically significant interactions remains absent).
Regulatory Status
Maca has not been approved by the European Food Safety Authority (EFSA) for any health claims. In the United States, it is marketed as a dietary supplement under the Dietary Supplement Health and Education Act (DSHEA), which means manufacturers can sell it without pre-market approval, but cannot make disease claims.
Typical Dosing
Clinical trials typically use 1,500–3,000 mg of dried root powder daily, divided into one or more doses. Some formulations contain standardized extracts at lower doses (e.g., 600–1,000 mg), though the potency and consistency of these products vary widely.
Bottom Line
Maca presents an interesting case of a traditionally used plant with some positive signals in small human trials, primarily for sexual desire and well-being. However, the evidence base is modest in size, often limited by small sample sizes and short follow-up periods. The mechanism remains unclear, and effects on hormones—one of the main selling points—are inconsistently demonstrated. For individuals seeking to improve sexual function or menopausal symptoms, maca may be worth exploring as a low-risk trial, particularly if guided by a knowledgeable practitioner. However, it should not be considered a proven therapy for these conditions, nor should marketing claims about hormone optimization be trusted without further evidence. Larger, well-designed trials and longer-term safety studies would help clarify its true benefits and risks.