Why Does Maca Have a Prop 65 Warning?

January 2, 2026 •

4 min read

According to the California Office of Environmental Health Hazard Assessment (OEHHA), over 900 chemicals are on the Proposition 65 list, triggering warnings for countless consumer products, including maca. The primary reason why maca has a Prop 65 warning is the potential for trace amounts of naturally occurring heavy metals, like lead, absorbed from the soil during cultivation.

Quick Summary

The Proposition 65 warning on maca products is due to trace amounts of naturally occurring heavy metals like lead. This California law has extremely low thresholds for listed chemicals, which are often far below federal safety standards. Choosing reputable brands that conduct third-party testing can help minimize exposure and ensure product safety.

Key Points

Lead Contamination: Maca products often receive a Prop 65 warning due to trace amounts of naturally occurring heavy metals like lead, absorbed from the soil during cultivation.
Strict California Law: Proposition 65 has extremely low warning thresholds for chemicals, which are often significantly more stringent than federal safety standards set by the FDA.
Natural vs. Added Chemicals: The lead in maca is not intentionally added but is a natural contaminant from the plant's growth environment, especially in high-altitude regions like the Andes.
Not an Immediate Danger: The warning doesn't indicate an unsafe product, but rather that a listed chemical is present above the very low warning level specified by the state of California.
Third-Party Testing: Consumers can ensure safety by choosing reputable brands that perform and share third-party lab testing results, often via a Certificate of Analysis (COA).
Informed Choice: Understanding the context of the warning allows consumers to distinguish between a natural phenomenon and a genuine safety hazard, enabling them to make better purchasing decisions.

Understanding California's Proposition 65

California's Proposition 65, officially known as the Safe Drinking Water and Toxic Enforcement Act of 1986, is a state law designed to protect the public from significant exposure to chemicals that cause cancer or reproductive harm. It requires businesses to provide a clear and reasonable warning before exposing individuals to any of the listed chemicals. While the law's intent is to inform, its strict regulations and low threshold for warnings have led to consumer confusion, especially concerning natural products like maca.

The Heavy Metal Connection

The key reason maca often carries a Prop 65 warning is the potential presence of heavy metals, particularly lead. Unlike synthetic chemicals, these heavy metals are not intentionally added to maca but are absorbed naturally from the soil where the plant is grown. The volcanic and high-altitude Andean soils where maca is native can naturally contain trace elements of lead and cadmium. While this is a natural phenomenon, Prop 65 regulations require warnings for exposure levels far lower than federal safety guidelines.

Interpreting the Warning

A Prop 65 warning on a maca product does not mean the product is unsafe or will cause harm. It simply indicates that the product contains at least one of the listed chemicals in an amount that requires a warning under California law. The warning threshold for lead, for example, is set at 0.5 micrograms per day for reproductive harm, a level 1,000 times lower than the no-observable-effect level. This conservative approach often flags products that contain minute, naturally occurring quantities of substances also found in common foods like spinach or chocolate.

Navigating Supplement Quality and Safety

For consumers concerned about supplement safety, focusing on product transparency and sourcing is key. Reputable companies that sell maca often implement rigorous third-party testing to ensure their products fall well below even the strict Prop 65 limits. This testing screens for heavy metals and other potential contaminants, providing an extra layer of assurance for consumers.

How to Vet Your Maca Supplier

Source Transparency: Look for companies that specify where their maca is sourced. Peruvian-grown maca is generally considered superior and is often subject to stricter oversight.
Third-Party Testing: Manufacturers that use independent labs to test for heavy metals and other contaminants can provide a Certificate of Analysis (COA) to prove their product's purity.
Organic Certification: While organic status doesn't eliminate all heavy metal risk, it does ensure no pesticides or herbicides were used, which can contribute to contamination.
Reputation and Reviews: Research the brand's history and consumer feedback regarding product quality and transparency.

Maca Source Comparison


Feature	Peruvian Maca	Chinese-Cultivated Maca
Origin	Native to the high Andean plateaus of Peru.	Cultivated in non-native locations, such as China's Yunnan province.
Soil Composition	Grown in mineral-rich, often volcanic, soil that can naturally contain trace heavy metals.	Can have potential toxic features due to different growing conditions and agricultural practices.
Quality	Considered superior in potency, aroma, and taste by many experts.	May exhibit different characteristics; some reports mention adulteration with other powders.
Safety Measures	Experienced farmers and reputable manufacturers conduct soil and product testing for heavy metals.	Quality can vary, making it essential to vet suppliers carefully for robust testing protocols.

The Larger Context of Prop 65 and Supplements

Prop 65 has a broad scope, affecting a wide array of products, not just dietary supplements. The stringency of the law can sometimes overshadow the actual risk posed by low-level, naturally occurring substances. This has led to manufacturers adding warnings out of legal precaution, even when the levels are considered negligible by federal standards like the Food and Drug Administration (FDA). The FDA regularly monitors food and supplement products and has different thresholds for safety, which can differ significantly from California's Prop 65.

In conclusion, the Prop 65 warning on maca products is primarily due to the potential presence of naturally occurring heavy metals like lead, which are absorbed from the soil. While the warnings can be alarming, they are triggered by extremely low, non-harmful levels according to federal standards. Consumers can make informed decisions by choosing transparent and reputable brands that provide third-party testing results for their products.

Conclusion: Making an Informed Choice

Ultimately, understanding why maca has a Prop 65 warning requires looking beyond the label to the nuanced regulatory landscape and the natural origin of the product. The warning is a result of California's very strict heavy metal thresholds, which are often surpassed by naturally occurring amounts in the maca plant. For most people, the trace levels of lead are far too minimal to cause concern. By seeking out brands that provide proof of third-party testing, consumers can confidently navigate the market and enjoy the benefits of this superfood with peace of mind. For more information on Proposition 65, including the full list of chemicals, visit the California Office of Environmental Health Hazard Assessment website.

Frequently Asked Questions

A Prop 65 warning on a maca product means it contains at least one of the chemicals listed by the state of California, typically a heavy metal like lead, in an amount that triggers the warning requirement. The presence of this warning is a legal formality based on a very conservative threshold and does not necessarily imply a health risk.

For most people, maca with a Prop 65 warning is safe to consume. The trace amounts of heavy metals are often naturally occurring and fall well within federal safety guidelines. However, pregnant or nursing individuals should consult a healthcare provider.

Heavy metals get into maca root naturally from the soil where it is cultivated. Maca is typically grown in volcanic soil high in the Andes Mountains, which can contain trace elements of lead, cadmium, and other minerals.

Not necessarily. While some contamination can occur, the presence of heavy metals in maca is often a result of natural geological factors in the soil rather than industrial pollution. Reputable companies test for contamination to ensure safety.

Finding a maca product without a Prop 65 warning is difficult, as the law's strict threshold applies to most natural products. Instead of focusing on the warning, look for brands that provide independent third-party lab testing results, or a Certificate of Analysis (COA), proving low heavy metal levels.

Yes, many other natural foods and supplements carry Prop 65 warnings for similar reasons. Trace amounts of naturally occurring substances can be found in items like cacao, coffee, and even some vegetables, triggering the same warning.

Prop 65 limits are often significantly lower and more conservative than federal limits. For example, the Prop 65 lead warning level is 1,000 times lower than the no-observable-effect level, leading to warnings for amounts considered non-harmful by agencies like the FDA.