Maca is unlikely to harm your liver. The National Institutes of Health’s LiverTox database, which tracks supplement and drug safety, gives maca a likelihood score of E for liver injury, meaning it is an “unlikely cause of clinically apparent liver injury.” Multiple clinical trials lasting up to 12 weeks have found no signs of liver toxicity at standard doses, and even unusually high intakes have not produced liver damage in study participants.
That said, there is one documented case of liver injury linked to maca, and the details are worth understanding if you’re a regular user or considering starting.
What Clinical Trials Show
Human studies have tested maca powder capsules at doses of 2 to 3 grams daily for 12 weeks without reporting serious adverse effects. One trial went much further, giving participants 115 grams per day of fresh micro-pulverized maca for 60 days. Even at that extreme dose, researchers found no evidence of liver or kidney toxicity.
Across small clinical trials, maca extracts have consistently been described as safe and well tolerated, with only minor, temporary side effects. Liver enzyme levels, the standard markers doctors use to check for liver stress, have not shown meaningful elevations in these studies.
The One Documented Case of Liver Injury
A single case report, published in the Chinese Medical Journal in 2017, described a 30-year-old man who developed jaundice within days of drinking 300 milliliters of “maca medicinal liquor.” His liver enzyme levels spiked dramatically, with ALT reaching 1,886 U/L (normal is roughly 7 to 56). Doctors diagnosed him with drug-induced liver injury attributed to maca, and his liver function gradually returned to normal over one to three months.
This case is important context, but it comes with caveats. “Medicinal liquor” is a traditional preparation where plant material is steeped in alcohol, sometimes with other herbs or additives. It’s unclear whether the maca itself, a contaminant, the alcohol base, or some interaction between ingredients caused the reaction. The LiverTox database notes that there have been “no convincing reports” linking maca to liver injury overall, and this single case has not been replicated.
One small study also observed a modest increase in AST (another liver enzyme) in volunteers taking just 0.6 grams of maca daily. The elevation was moderate and not considered clinically dangerous, but it suggests individual responses can vary.
Maca May Actually Protect the Liver
Animal research suggests maca could have the opposite effect of what you might worry about. In mice given a chemotherapy drug that damages the liver, maca polysaccharides significantly reduced liver enzyme elevations, lessened visible tissue damage, and lowered markers of oxidative stress. The protective mechanism appears to involve maca activating a cellular defense system that boosts the production of antioxidant enzymes and detoxifying proteins. Essentially, maca helped liver cells resist damage from toxic free radicals and maintained their energy-producing functions.
These are animal findings, so they don’t directly prove the same thing happens in humans. But they do suggest maca’s natural compounds are more likely to support liver cells than harm them under normal conditions.
Watch Out for Adulterated Products
One genuine liver risk with maca has nothing to do with maca itself. The FDA has issued warnings about products marketed under the maca name that contain hidden pharmaceutical ingredients. A product called “Peru Maca” was found to contain sildenafil, the active ingredient in Viagra, which was not listed on the label. Hidden drugs like this can absolutely cause liver stress, especially if combined with other medications.
This is a supply chain problem, not a maca problem. But it means where you buy matters. Stick to reputable brands that provide third-party testing. If a maca supplement promises dramatic results for sexual performance, treat that as a red flag that it may contain undeclared drug ingredients.
Practical Dosing Guidelines
The doses shown to be safe in clinical trials range from 2 to 3 grams of maca powder per day, taken for up to 12 weeks. This is the range most commercial supplements fall within. There’s no established safe upper limit from regulatory agencies, but the human trial using 115 grams daily of fresh maca without liver effects suggests a wide margin of safety for typical supplement doses.
If you have an existing liver condition, the picture is less clear. No studies have specifically tested maca in people with fatty liver disease, hepatitis, or cirrhosis. The overall safety profile is reassuring, but a liver that’s already compromised may respond differently than a healthy one. Starting at a lower dose and monitoring how you feel is a reasonable approach.