Avoid in individuals with a known allergy or hypersensitivity to maca (Lepidium meyenii).
Side Effects and Warnings
Available studies in humans have only been performed on male subjects. In these trials, no side effects were noted and maca was generally considered safe. Maca has not been studied in women.
Maca may cause changes in some sex hormones, although animal studies have demonstrated conflicting results. Preliminary evidence from studies in humans has failed to show that maca induces changes in luteinizing hormone, follicle stimulating hormone, prolactin, testosterone, and estradiol. However, use cautiously in patients with hormone responsive cancers such as breast cancer, or prostate cancer, and patients who are using birth control pills due to the potential effects of maca on sex hormone regulation.
Consumption of large amounts of maca may cause bloating and flatulence. Consumption of fresh maca may cause stomach pain.
The use of maca may increase leukocytes. The use of maca may decrease PT/INR values in patients being monitored for anticoagulation therapy.
Maca may also lead to stimulation of the central nervous system. Use cautiously in patients with hypertension (high blood pressure), due to the possibility of central nervous system stimulation.
Pregnancy and Breastfeeding
Maca is not recommended in pregnant or breastfeeding women due to a lack of available scientific evidence.
Adults (18 years and older):
Maca is likely safe when consumed by healthy adults in doses of 1,500-3,000 milligrams per day for up to four months as an aphrodisiac or to improve spermatogenisis, however, there is no proven effective dose for maca. Traditionally, up to 6,000 milligrams or more per day in divided doses has been used. Root powder containing 2,800 milligrams of maca root placed in 8 ounces of water has also been used up to three times daily. Commercially prepared concentrated extracts containing 450 milligrams taken twice daily has been used as well.
Common dietary consumption in native populations is greater than 100 grams, or equivalent to greater than 1.4g per kilogram, daily.
Children (younger than 18 years):
There is no proven safe or effective dose of maca, and use in children is not recommended.
Interactions with Drugs
Plants in the Brassicaceae family, such as maca, are often rich in vitamin K. Thus, maca may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).
Maca may act as a stimulant and cause hypertension (high blood pressure). Patients taking medication for high blood pressure, or those taking other stimulant medications, should consult with a qualified healthcare professional, including a pharmacist, before combining therapies.
Maca may alter the levels of sex hormones, and may interfere with the effects of hormone replacement therapy or birth control pills. Caution is advised.
Interactions with Herbs and Dietary Supplements
Plants in the Brassicaceae family, such as maca, are often rich in vitamin K. Maca may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases
Maca may act as a stimulant and cause hypertension (high blood pressure). Patients taking herbs or supplements for high blood pressure, or those taking other stimulants, should consult with a qualified healthcare professional, including a pharmacist, before combining therapies.
Maca may alter the levels of sex hormones, and may interfere with the effects of herbs or supplements with hormone effects, such as St. John's wort or chasteberry.