Some believe maca root enhances fertility and improves sexual performance, but is it the real deal? What does the science say about this herb, sometimes called Peruvian ginseng? Find out here.
What is Maca?
Maca (Lepidium meyenii) is a cruciferous vegetable native to the Andes mountains of Peru. It looks like a radish or turnip and is consumed both as a dietary staple and as a medicinal herb. The main edible part of maca is the root.
Also known as Peruvian ginseng, maca has been used by traditional cultures living in Peru for thousands of years as an aphrodisiac and to support life in the harsh mountain climate. Inca warriors consumed maca for strength in battle [1].
There are 13 maca variations, named for the color of their roots. In some cases, different colors of maca can produce different biological effects [2].
The most commonly studied colors are yellow, black, and red.
Maca Constituents
Maca contains 10% water, 59% carbohydrates, 10 to 14% protein, 8.5% dietary fiber, and 2.2% fat [3, 4].
A 7 g (1 tablespoon) serving of maca root powder contains 20 calories, 4 g carbohydrates, 1 g protein, and 0 g fat.
Maca is rich in calcium, potassium, iron, and iodine. It also contains copper, manganese, zinc, vitamin C, riboflavin (vitamin B2), and thiamine (vitamin B1) [4].
Maca contains 20 different fatty acids (including linolenic, palmitic, and oleic acids), and 19 amino acids.
Red and black maca have high levels of choline [2].
The main active compound in maca is the alkaloid macaridine. It has not been found in any other plant [5].
Maca also contains macamides, which are fatty acids unique to maca.
Glucosinolates are active components of maca and contribute a bitter flavor. Fresh maca has 10 times the glucosinolates of other cruciferous vegetables. Red maca has the most glucosinolates, followed by black and yellow [6, 7].
Maca also contains dietary polyphenols which vary depending on the color of the root [8].
Maca also contains a compound (MTCA), which inhibits monoamine oxidase (MAO – an enzyme that breaks down certain transmitters) and has shown the ability to mutate DNA in cell studies [9].
Mechanisms of Action
- Maca contains macamides, which are fatty acids that affect the endocannabinoid system [10].
- Macamides increase anandamide levels by blocking fatty acid amide hydrolase (FAAH), an enzyme that breaks down anandamide [11].
- Anandamide acts on the cannabinoid CB1 receptor, which may produce feelings of happiness.
- Black maca reduces hemoglobin levels in individuals living at high altitude [2].
- Elevated hemoglobin levels at high altitude are associated with chronic mountain sickness [12].
- Maca neutralizes free radicals and protects against oxidative stress [13, 14].
- Maca increases total white blood cell levels (in fish) [15].
- Maca increased IGF-1 levels in human cartilage, which may be responsible for Maca’s benefit to bone health [14].
- Maca decreases angiotensin-converting enzyme (ACE) activity, which lowers the availability of angiotensin, a hormone that raises blood pressure [16].
Health Benefits
Maca supplements have not been approved by the FDA for medical use and generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.
Insufficient Evidence For
The following purported benefits are only supported by limited, low-quality clinical studies. There is insufficient evidence to support the use of maca for any of the below-listed uses. Remember to speak with a doctor before taking maca supplements, and never use it in place of something your doctor recommends or prescribes.
1) Sex Drive & Sexual Function
Taking maca for 12 weeks increased sexual desire in a study (DB-RCT) of 57 healthy men [17].
In a study of 20 men and women, taking maca for 12 weeks improved antidepressant-induced sexual dysfunction and increased sex drive. These effects were strongest with 3 g of daily supplementation [18].
In a study of 8 men, maca extract taken for 2 weeks increased sex drive [19].
Maca extract taken for 12 weeks increased erectile function and sexual well-being in a study (DB-RCT) of 50 men with mild erectile dysfunction [20].
In a study (DB-RCT) of 14 healthy postmenopausal women, 6 weeks of maca supplementation reduced sexual dysfunction [21].
Black maca increased sperm count, volume, and quality in a study of 9 healthy men [22].
These studies are not large enough to definitively say that maca increases sex drive or improves sexual function, but they are very promising. Larger, more powerful studies will provide more information.
2) Anxiety and Depression
Maca taken for 6 weeks lowered anxiety and depression symptoms in small studies of a total of 43 postmenopausal women [21, 23].
In a study of 197 people, 12 weeks of maca supplementation improved mood, reduced fatigue, and increased reported quality of life [2].
In rats, maca reduced depression-like behaviors [24].
These results are promising, but future studies will need to repeat them with larger samples under more rigorous conditions.
3) Blood Pressure
Maca consumption was associated with low blood pressure in an observational study of 50 people [25].
In a study (DB-RCT) of 29 postmenopausal women, 6 weeks of maca supplementation lowered blood pressure [23].
Additional human studies with larger groups of people will be required to further investigate maca’s effects on blood pressure.
4) Bone Health
Reparagen, a compound comprised of 83% maca, decreased pain and stiffness, and improved physical function in a study of 95 osteoarthritis patients [26].
In a pilot study of 12 menopausal women, maca increased bone density over 4 months [27].
Maca also prevents bone loss due to reduced estrogen levels in rats [28, 29].
5) Menopause
Maca reduced menopausal symptoms (irritability and discomfort from hot flashes and night sweating) in a study of 124 postmenopausal women [30].
Maca powder taken for 2 months lowered follicle stimulating hormone and luteinizing hormone, and increased estrogen and progesterone in a study of 20 postmenopausal women [31].
6) Inflammation and Oxidative Stress
In a study of 50 people, those who regularly consumed maca had lower levels of inflammatory markers (IL-6) than those who did not. Larger human trials will be required to repeat this observation and determine maca’s effect on inflammation [25].
Black maca decreased markers of oxidative stress in mice [32].
7) Blood Sugar
Black maca lowered blood glucose in a study of 197 adults. This is a promising initial result, but more human studies will be required [2].
8) Exercise Performance
In a pilot study of 8 endurance cyclists, 2 g of maca taken for 2 weeks improved cycling performance. Again, larger and more powerful human studies will be required to repeat and confirm this benefit [19].
9) Chronic Mountain Sickness
Chronic mountain sickness is a lack of adaptation to high altitude [12].
Maca consumption was associated with reduced prevalence of chronic mountain sickness in a study of adults [33].
Maca consumption was associated with high health-related quality of life in a study of 50 adults living at high altitude [25].
Red maca lowered chronic mountain sickness symptoms in a study of 197 adults [2].
Animal & Cell Research (Lacking Evidence)
No clinical evidence supports the use of maca for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
10) Cognitive Function
Maca improved learning in mice, with black maca showing the strongest effects [24].
Black maca protects against memory impairment in mice [34, 35, 32].
11) Enlarged Prostate
In animals with enlarged prostates due to excess testosterone, red maca extract reduced prostate size [36, 37].
12) UV Exposure
Maca extract applied to the skin of rats protected from UV radiation [38].
Red, black, and yellow maca applied to the skin of rats prevented the development of sunburnt cells and other signs of UV damage. Maca also showed substantial antioxidant effects [39].
Limitations
Much of the clinical research above has been performed by one lab in Peru, so use caution when interpreting the results. Additional studies from other countries, performed in different patient populations and with larger samples, are required to determine whether the Peruvian results are significant.
Using Maca
Side Effects
Residents of the Andes Mountains in Peru consume up to 100 g of maca per day without side effects [40].
However, natives advise consuming only dehydrated or boiled maca root because raw maca may cause health issues [1].
In clinical studies, maca is well-tolerated up to 3 g/day [41].
In an isolated study, 0.6 g/day of Maca for 90 days increased levels of a marker of liver damage (aspartate aminotransferase) and diastolic blood pressure in 95 patients with metabolic syndrome [42].
Maca contains a compound that can mutate DNA (MTCA) [9].
Given this danger, maca has been warned against by certain food safety agencies. However, this is disputed by researchers who claim that MTCA is inactivated when it is boiled [43].
Side effects reported by maca users include an altered menstrual cycle, stomach cramps, moodiness, and insomnia [44].
To avoid these and other unexpected adverse events and interactions, always talk to your doctor before trying a new supplement.
Sources and Dosage
Maca can be supplemented as a powder, pill, capsule, flour, liquor, and extract. It is most commonly sold as a powder or capsule (which contains the powder).
Maca powder is widely available in two forms: dehydrated (often marketed as “raw” or “dried”) maca powder or gelatinized maca powder.
Raw maca powder retains most of its nutrients but may be difficult to digest because of its fiber content.
Gelatinized maca powder is boiled and pressurized to remove the fiber and make it easier to digest. However, some nutrients may be lost in this process.
In most studies, the standard dose of maca is 1.5-3 g/day dehydrated or gelatinized powder taken as a capsule.
Maca root powder has an earthy or nutty taste. Red maca is the sweetest and mild. Yellow maca is the most bitter, and black maca is in between.
Drug Interactions
Maca has not produced any reported drug interactions [45].
Takeaway
Maca root is a Peruvian root vegetable rich in nutrients, polyphenols, and other active compounds. It is traditionally boiled or dehydrated and consumed to increase sexual desire. Limited clinical evidence supports this use, though further study is required.
According to other small clinical studies, maca may have some use in anxiety, blood pressure, bone health, inflammation, altitude sickness, and more. However, there are better-studied alternative strategies for each of maca’s reported benefits.
