Maca Supplements Review
Initial Posting: 6/26/15 Updated: 4/13/19
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Summary: What You Need to Know About Maca Supplements
- Maca root is sold as a starchy powder or gelatinized powder (which may be more digestible), and as extracts (see "What It Is"). Most clinical studies have used the root powder or gelatinized root powder and may, therefore, be preferable to extracts.
- Maca is commonly used to increase stamina and sexual function and improve mood, based on traditional use and evidence from preliminary clinical studies, but there are no large, well-controlled, long-term studies to support these uses. Maca does not appear to affect sexual hormones in men or women. (See "What It Does")
- Maca root powder has been consumed for centuries as a food source and is considered fairly safe, but reported side-effects include headache, stomach upset, sleep disruption and increased sweating and it may affect liver function and blood pressure. (See "Concerns and Cautions")
- A typical dosage of maca root powder used in clinical studies is 1,500 to 3,000 mg (less than one teaspoonful), which can be as loose powder mixed with water or into a beverage, or as several capsules. Capsules typically contain about 500 mg of powder. (See "What to Consider When Buying and Using")
- Testing by ConsumerLab.com of maca supplements found several to appear to be authentic based on DNA and microscopic testing. However, one product could not be Approved by ConsumerLab.com due to contamination with lead. (See "What CL Found")
- Among CL Approved products, the lowest cost per gram (1,000 mg) of powder was 10 cents from a loose maca powder or 12 cents from a loose gelatinized maca root powder. Maca in capsules generally cost a bit more than loose maca powders. (See "Top choices")
What It Is:
Maca (Lepidium meyenii) is a starchy root vegetable, related to the turnip which grows at high altitudes in Peru, although it is now grown in other countries, including China. It is consumed as a food in Peru and neighboring countries, and used to make flour. It has a similar nutritional profile to grains such as rice and wheat, containing a combination of large amount of carbohydrate (including fiber), protein, fatty acids, and various vitamins and minerals. Maca root also contain small amounts of compounds called macamides, which may be responsible for some of its reported effects, although evidence as to what these compounds may do remains preliminary. No official guidelines (such as those set by the USP) have been established regarding the amounts of macamides or other compounds to be expected of authentic maca products.
What It Does:
Maca has been promoted for a wide range of uses, including increasing energy, stamina, and sexual ability, improving mood, and boosting the immune system. Maca is sometimes referred to as "Peruvian ginseng" as these uses overlap those promoted for ginseng. The claimed uses of maca are based largely on its traditional use and several small clinical studies, noted below, some of which lacked a placebo control. Larger, well-controlled, long-term studies are needed.
Sexual desire, dysfunction and mood:
As described below, results of several small and short-term (lasting 12 weeks or less) studies suggested that maca can help men with aspects of sexual functioning, although larger studies are needed. The evidence for women is mixed.
One clinical study in men ages 21 to 56 found that maca tablets (Maca Gelatinizada La Molina, Laboratorios Hersil (Peru)) taken daily for 8 weeks (providing either 1,500 or 3,000 mg per day of gelatinized, dried maca root powder) significantly increased sexual desire compared to a placebo, although the higher dose of maca did not have more of an effect than the lower dose (Gonzales, Andrologia 2002). There were no changes in blood levels of testosterone and estrodiol, and no improvement in scores of depression or anxiety. Another study in 9 men reported that same maca tablets (providing either 1,500 or 3,000 mg of maca daily) significantly increased semen volume, total sperm count, motile sperm count, and certain measures of sperm motility (Gonzales, Asian J Androl 2001). However, this study did not include a control group.
In a study in young men (average age 36) with mild erectile dysfunction, those who took 2,400 mg of dried maca extract daily for 12 weeks had a slight, but significant improvement in erectile function compared to those taking a placebo (Zenico, Andrologia 2009) — those with the most erectile dysfunction at the beginning of the study experienced the most improvement. The men taking the maca also had a significant improvement in certain measures of daily life satisfaction, specifically, physical and social performance, compared to the placebo group.
A study among 47 healthy men and women ages 18 to 53 found that, compared to placebo, 2,100 mg of a patented blend of black and red maca powders (Lepidamax, Nutrition21) taken as three 700 mg capules daily for 28 days improved hand-grip strength, and self-reported fatigue and sexual functioning (including arousal and satisfaction) in men. There was some improvement among women, but this was not statistically significant (Jiannine, J Exerc Nutr 2019).
A study in 14 postmenopausal women found that those who took 3,500 mg of maca powder daily for 6 weeks had significant improvement in psychological symptoms, including decreases in anxiety and depression (27.3% and 26.8%, respectively) compared to those who took a placebo. The women who took maca also had a 34.6 % decrease in measures of sexual dysfunction compared with those in the placebo group (Brooks, Menopause 2008). There were no significant changes in blood levels of estradiol, follicle stimulating hormone (FSH), luteinizing hormone (LH) or sex-hormone-binding globulin (SHBG).
A study comparing the effects of 1,500 mg and 3,000 mg of maca root powder in 17 women and three men with sexual dysfunction associated with the use of SSRI antidepressant medication found that those taking the 3,000 mg dose had a significant improvement in measures of sexual dysfunction such as sexual desire (libido) and number of enjoyable experiences (Dording, CNS Neurosci Ther 2008) in comparison to before taking maca. There was also a small but significant decrease in measures of depression and anxiety in the higher-dose group. However, this study did not include a placebo, making it impossible to determine if the effects were based on expectations, i.e., a "placebo effect." A small number of adverse events such as headache, stomach upset, sleep disruption and increased sweating were reported.
As noted earlier, 2,100 mg of a patented maca blend (Lepidamax, Nutrition21) taken daily for 28 days improved self-reported fatigue and sexual functioning (including arousal and satisfaction) in healthy women (ages 18 to 53) but these improvements were not significant compared to placebo (Jiannine, J Exerc Nutr 2019).
For information about other supplements for sexual enhancement and tests of related products, see the Review of Sexual Enhancer Supplements (with Yohimbe, Horny Goat Weed, Arginine).
Although maca is sometimes promoted to reduce osteoarthritis pain, there is little evidence for this use. A laboratory study showed that branded maca extract (RNI 249®) increased levels of IGI-1 (growth factor) in cells of cartilage samples taken from patients with osteoarthritis of the knee (Miller, BMC Complement Altern Med 2006). A supplement (Reparagen®, Rainforest Nutritionals Inc.) containing a combination of 1,500 mg of RNI 249® maca extract and 300 mg of cat's claw taken twice daily for 8 weeks was found to reduce pain in adults with knee osteoarthritis similarly to treatment with 1,500 mg of glucosamine sulfate. Ninety-four percent of the group taking Reparagen® and 89% of the glucosamine group had at least a 20% reduction in knee pain (Mehta, BMC Complement Altern Med 2007). However, because this study did not compare these treatments with a placebo, it is not possible to conclude whether maca truly decreased pain. Additionally, taking cat's claw (without maca) has been shown in at least one clinical trial to reduce knee osteoarthritis pain.
(For information about other supplements for Joint Health, see the Review of Glucosamine, Chondroitin, MSM and Boswellia Supplements for Joint Health).
Based on research in animals, maca has also been promoted for stress, diabetes, prostate enlargement and other conditions. However, there is insufficient evidence in people for these uses.
See the Encyclopedia article about Maca for more information.
Quality Concerns and What CL Tested for:
Neither the Food and Drug Administration (FDA) nor any other federal or state agency routinely tests supplements for quality prior to sale. In order to help consumers identify products of better quality, ConsumerLab.com purchased and tested maca supplements.
Although ConsumerLab.com normally tests botanical supplements for expected amounts of plant chemicals, the precise chemical makeup of maca has not been well-defined, so ConsumerLab.com analyzed the products for maca DNA and evaluated the products microscopically to check for potential adulteration with unlabeled ingredients or incorrect plant parts. Limitations of these analyses are that the DNA test cannot determine the actual amount of maca, just whether or not it is present, and the microscopic evaluation cannot distinguish maca root from similarly structured roots.
ConsumerLab.com also tested products for amounts of lead, cadmium and arsenic — heavy metals which can occur in plant-based products and are toxic contaminants. Any products in regular tablet or caplet form also underwent disintegration testing to determine if it would break apart properly in solution.
See How Products Were Evaluated for more information on testing.
(6/30/2015): It was reported to CL that the supplement company selling the maca product which was contaminated with lead has claimed that CL's results were "exaggerated" and that the product must contain a lower amount of lead to meet the company's specfications which are monitored by third party audits.
The suggestion CL's results are "exaggerated" is incorrect. CL's findings were confirmed in a second independent laboratory prior to publication. That laboratory found a slightly higher amount of lead than the first, but CL published the lower of the two, since that amount could be substantiated by both labs. Rather than an exaggeration, CL provided the most conservative figure.
More details are provided in the Update near the top of the full Review.