Heavy Metals in Protein Powders May Pose Safety Risk
Plant-based, organic, and chocolate protein powders contained the highest amounts of lead, according to a recent analysis.
Nearly half of protein powders evaluated in a recent analysis contained enough toxic heavy metals to exceed California Proposition 65 safety thresholds — one of the most stringent in the country, if not the world, experts say.
The study, conducted by the Clean Label Project, a nonprofit organization dedicated to transparent food labeling, found that 47 percent of the 160 protein powders tested exceeded California’s rigorous safety thresholds for heavy metals such as lead and cadmium.
Heavy metals can end up in our food through soil and water contamination as well as through manufacturing processes.
"There is an inextricable link between the health of our soils and waterways, our food, and public health," said Jaclyn Bowen, the executive director of Clean Label Project, in a press release.
While heavy metal contamination reform is underway at the state and federal level for foods marketed toward children, the same conversations need to be happening when it comes to the rest of our food supply, said Bowen.
“Athletes of all capabilities reach for protein powder to supplement their already healthy lifestyle choices. This serves as another proof point on the extent of the contamination in our food supply and the need for federal food safety regulatory leadership.”
The popularity of protein powders has surged in recent years, with the U.S. protein supplements market surpassing $9 billion in 2023. In general, the products are marketed as a quick, convenient way to support fitness goals, weight management, and overall wellness.
Protein Powder Tests Focused on Top-Selling Brands
To review potential contaminants in protein powders on the market, the organization purchased 160 products from 70 of the top-selling brands, representing 83 percent of the market share. Researchers then conducted more than 35,000 individual tests for a range of contaminants, including heavy metals (lead, cadmium, arsenic, mercury), bisphenols (BPA and BPS), and other industrial chemicals.
Key findings from the report include:
On average, organic protein powders had three times more lead than non-organic products. Lead contamination in protein powders is concerning because there is no safe level of lead exposure, according to the U.S. Environmental Protection Agency (EPA).
Plant-based protein powders, such as those made from soy, rice, and peas, contained three times more lead than whey-based protein powders.
Plant-based powders had five times more cadmium than whey-based products. Cadmium is a known carcinogen and is toxic to several organs, including the kidneys, liver, and bones.
Chocolate Protein Powders Contain More Heavy Metals
On average, chocolate-flavored protein powders tested for the study contained four times more lead and up to 110 times more cadmium than vanilla-flavored varieties.
This is likely due to the natural heavy metal absorption properties of cacao, the primary ingredient in chocolate flavoring. Metals may be incorporated into cocoa beans from soil or water as the plants grow. Contamination could also occur during the manufacturing process.
Findings in Line With Other Studies on Toxic Metals in Food
The key finding — that nearly half of the 160 protein powders tested exceeded California’s Proposition 65 (Prop 65) safety thresholds for toxic metals — isn’t surprising, says Jacob M. Hands, a research associate in the Frame-Corr Lab at the George Washington University in Washington, DC.
Hands authored recent research on heavy metals found in cocoa powders and chocolate. He is not associated with the Clean Label Project.
“These findings are in line with what other studies have reported, and part of that is because the Prop 65 standard is one of the strictest standards in the entire country, if not in the world,” says Hands.
The California initiative, passed almost 40 years ago, set acceptable levels for dangerous chemicals and toxins by identifying the level of exposure that has been shown to not pose any harm to humans or laboratory animals. Proposition 65 then requires this “no observable effect level” to be divided by 1,000 in order to provide an ample margin of safety.
Businesses subject to Proposition 65 are required to provide a warning if they cause exposures to chemicals listed as causing birth defects or reproductive harm that exceed 1/1,000th of the “no observable effect level.”
“This high standard isn’t a bad thing, but it has the potential to falsely generate a lot of anxiety in consumers,” Hands says.
The report doesn’t include the actual amounts of the toxins found, but rather just how many products were over the Prop 65 threshold. Without that information, it’s difficult to know how concerning these findings are, says Hands.
Critics of the Report Cite Lack of Transparency in Testing and Product Selection
The Natural Products Association, an industry trade association for dietary supplements and natural health and sports nutrition, criticized the report for not providing enough transparency about its testing methods, product selection process, and the source of funding for the report.
The Council for Responsible Nutrition (CRN), a trade association that represents diet supplements (including protein powders) also took issue with the Clean Label report.
“The Council for Responsible Nutrition supports efforts to ensure the safety and quality of dietary supplements, including protein powders. However, as we have noted in the past, reports like those issued by the Clean Label Project often lack critical context and risk misleading consumers rather than empowering them,” said Andrea Wong, PhD, of CRN, in a statement.
While applauding efforts to keep products safe and untainted for consumers, CRN urged the authors of the report “to publish its findings in peer-reviewed journals and provide recommendations grounded in scientific evidence.”
What Can People Who Buy Protein Powders Do?
For people who want to buy powders that are as “toxin-free” as possible, the authors of the report offer the following recommendations.
Choose whey-based or collagen-based powders. These protein sources generally have lower levels of heavy metals than plant-based options.
Select vanilla-flavored products. Chocolate-flavored protein powders tend to have higher levels of lead and cadmium.
Inquire about contaminant testing. Contact your favorite protein powder brands to ask about their testing practices for heavy metals and other chemicals.
Shop for trusted brands. Look for brands that emphasize transparency and quality control, particularly those that have third-party testing for contaminants.
