Maca root is a Peruvian plant used primarily to boost libido, support fertility, ease menopause symptoms, and improve energy. Most clinical trials use doses between 1.5 and 3 grams per day, and effects on sexual desire and endurance typically show up within a few weeks. While maca has a long history as a food crop in the Andes, modern research is still catching up to its reputation, with some benefits well-supported and others preliminary.
How Maca Affects Libido and Sexual Function
The most consistent finding across maca research is an improvement in sexual desire. This effect has been observed in both men and women, including people whose low libido was caused by antidepressant medications. In a dose-finding study of 20 adults with antidepressant-related sexual dysfunction, the higher dose of 3 grams per day was more effective at restoring sexual function than 1.5 grams per day.
What makes maca unusual is that it appears to improve desire without changing hormone levels in the blood. Studies measuring testosterone, estrogen, and other sex hormones before and after supplementation generally find no significant shifts. Researchers believe maca’s effects on libido come from its unique compounds, particularly macamides, which are found exclusively in this plant and may interact with the body’s endocannabinoid system rather than the hormonal pathway.
Effects on Male Fertility
Maca shows promising effects on sperm quality, though the studies are small. In a double-blind pilot study of healthy men who took maca for 12 weeks, total sperm count increased by 20%, sperm concentration by 14%, motile sperm count by 14%, and normal sperm shape by 21%. An earlier study of nine volunteers reported even larger improvements after 16 weeks: sperm concentration rose 35%, total count jumped 84%, and motile sperm count more than doubled.
Even in men with diagnosed infertility, there are signs of benefit. One study of ten infertile patients found a 10% increase in motile sperm and a 12% improvement in normal sperm shape after 12 weeks. These numbers are modest on their own, but they consistently trend in the same direction across studies, which is encouraging. Black maca specifically has been linked to the strongest fertility effects in comparative research.
Menopause Symptom Relief
For women in early postmenopause, maca may reduce hot flashes, improve sleep, and restore energy. In an eight-month trial using a combination maca product, women reported a noticeable reduction in hot flashes and night sweats, along with improvements in falling asleep, fatigue levels, and interest in sex. Some women in the study experienced relief from hot flashes in as little as four days to one week.
The improvements built over time. After two months, hot flash scores dropped to about 90% of the placebo group’s levels. By eight months, they had fallen further to roughly 82%. Night sweats were slower to respond, showing meaningful reduction only after several months of consistent use. Notably, this effect appears to work through the brain’s hormonal signaling pathways rather than by raising estrogen levels directly, which may make maca a different option than traditional hormone therapy.
Energy and Physical Performance
Maca has a reputation as an energizer, and there’s partial support for that in clinical research, though results are mixed. In one study, male cyclists improved their 40-kilometer time trial by about a minute after just 14 days of supplementation (2 grams per day). Animal studies consistently show that maca increases time to exhaustion during forced exercise, with higher doses producing stronger effects.
However, not every human trial shows a clear benefit. A study comparing maca extract to a placebo in healthy men found no significant difference in time to exhaustion. And a study of elite male athletes taking 5 grams of black maca found no improvements in strength, endurance, or agility. The pattern suggests maca may help more with sustained, moderate-intensity effort than with peak athletic performance, and that it works better in some populations than others.
Different Colors, Different Strengths
Maca roots come in several colors, and they are not interchangeable. Each phenotype has a somewhat different chemical profile, which translates to different strengths:
- Black maca has the strongest evidence for male fertility, physical endurance, memory, and blood sugar support. It’s the most studied variety for men’s health.
- Red maca stands out for prostate health (it inhibited prostate enlargement in animal studies), bone density, and skin healing. It also has notable anti-inflammatory properties.
- Yellow maca is the most commonly available and has moderate benefits across the board, with some evidence for female fertility and sperm production.
- Purple maca is less studied but shows antioxidant activity and potential blood sugar benefits.
Products that blend multiple colors have been tested specifically for menopause relief, where the combination appears to influence the brain’s hormonal control center more effectively than single-color varieties.
Dosage Used in Research
Clinical trials most commonly use 1.5 to 3 grams of maca per day, taken as powder or in capsules. The 3-gram dose tends to outperform the 1.5-gram dose for sexual function. Some athletic studies have gone as high as 5 grams per day. Most trials run 8 to 16 weeks, and effects on libido and sperm quality appear to build gradually over that window.
Maca is traditionally consumed as a cooked food, not raw. Gelatinized maca (which has been heated to remove starch) is the form used in most clinical research and is easier to digest than raw powder. If you’re buying a supplement, look for the specific color that matches your goal, and check whether the product specifies gelatinized or raw form.
Safety and Potential Concerns
Maca is generally well tolerated in clinical studies, with few reported side effects at standard doses. It has been eaten as a staple food in Peru for thousands of years, which provides some baseline safety data that most supplements lack.
One concern that comes up frequently is maca’s glucosinolate content. Glucosinolates are compounds also found in broccoli and cabbage that can interfere with iodine uptake in the thyroid when consumed in large amounts. For people with existing thyroid conditions, this is worth being aware of, particularly at higher doses or with long-term use. Maca also acts on hormonal signaling pathways in the brain, so people with hormone-sensitive conditions should approach it cautiously. The lack of direct effects on blood hormone levels is somewhat reassuring, but long-term safety data in these populations is limited.